Freshly Roasted Coffee & Solubles

It is accepted that Freshly Roasted Coffee Beans are essential to a great coffee experience.

This is a preliminary exploration of two brewing methods; modified Turkish and espresso.  The hypothesis is that it is possible to increase the G forces on the brew for accelerated sedimentation of the coffee fines.  The accumulation of solids in the bottom would support the idea that it is possible to quantify the coffee strength for various brewing methods.  For now, it is assumed that the amount of solubles is directly related to the strength of the coffee.

At the top is a modified Turkish brew without the addition of Cardamon and Cinnamon.  Essentially it is coffee made with a very fine grind which remains in the cup.  Of course if the drinker insists on consuming the proverbial last drop he/she will also have a 10 g breakfast.  For this comparison the water to coffee ground ratio of 10:1 was used.  The brew decanted for approximately 2 minutes before 14 ml were removed and placed into the vial or tube.

 The espresso was made with 15 g of coffee which was pulled in 29 seconds to yield two ounces or 60 ml.  Again, 14 ml was transferred to a tube for further processing or accelerated decantation.

The espresso grind is tamped in the porta-filter which only allows smaller particles to pass through with the water.

The fine grind, brew in a cup on the other hand is initially separated by gravity alone.  Since it is not filtered it is possible that the larger grounds are decanted in the first 2 minutes.  The larger the grind the longer it takes to decant but since this is an extra fine grind it is possible that the 2 minutes was sufficient to decant even the largest particles.  Smaller particles may be held in suspension in the liquid whether by turbulence, Brownian forces, or magic.

Both brews were initially opaque when held in front of a light.

The results above are open to interpretation until further experiments are done.  All three vials show signs of sedimentation but the Turkish Grind had significantly more grinds in the bottom.  It may be possible to conclude that the particles were larger than those in the espresso.  The increased transparency does support the premise that the previous opaqueness was due to the larger particles.

The espresso remained largely unchanged.  It is difficult to establish with precision that .25 ml of fines were decanted.  The opaqueness of the processed espresso does support the idea that extremely fine particles are held in suspension.

The experiment did not support the hoped for conclusion where the amount of solubles could be measured and even categorized.  It appears that a greater G force will be required to compare drip coffee, to say, a brew done in a French Press.  Or to compare the brew of large chains to that of a K cup.

Hopefully, another iteration of this test will allow the measurement of a solubles so that  brewing can be optimized.  Without measurement it is difficult to optimize so many variables.

Now, a cup of coffee is needed to start the process.

NXT Coffee Roaster Design not "off the shelf"

To Google Maps
Most coffee roasters are heated by  a natural gas flame.  Natural gas is a cheaper form of energy than electricity but it comes with inherent limitations.  Since the flame requires a continual supply of oxygen it requires a lot of air which must be raised from ambient to combustion temperature, this  is not the end of the energy waste.  The coffee roasting is usually done in the exhaust gasses of the flame which, are not hot enough after passing through the Roasting Chamber, to break down the roasting smoke.  That smell is similar to burnt toast, in the later stages, - imagine several kilo grams of burnt toast.  Hence, an Afterburner is required to raise the temperature to over a 1000°F to break down the smoke.  The large amount of air required by the flame means that a large amount of air must be raised from ambient temperature to over 1000°F.  Consequently, the Afterburner burns, depending on the model,  three times as much energy as the roaster (the equivalence of 6 home furnaces) just so that the neighbourhood will not see nor smell the roaster emissions.  Of course the emissions from such burners are always present but the operators hope that they become sufficiently diluted by the outside air that they will not trigger calls to the environmental agency.  Pollution awareness is upon us and some areas already require permits for coffee roasters with 5 kg or more capacity.

Are there alternatives?
There is, if the fabricator begins with a clean design slate rather than use off the shelf technologies.  First, the amount of air needs to be reduced to greatly reduce the waste of energy.  It is true that often the electricity is generated by the combustion of natural gas but the electrical companies have specialized equipment to remove and neutralize gas volatiles that individual roasters do not use.  Nevertheless, the electrical Roastaire™'s biggest advantage is virtually eliminating the continual feeding of air to the roasting process.  It is possible to recirculate the air with electrical heating because you do not need to feed a flame.  The advantage, is that less energy is required to heat the returning air than to heat room temperature air (ambient) to roasting temperatures.  There is less air to treat when neutralizing the emissions therefore it can be done on a continual basis. A minor advantage is that the oily smoke, as part of the re-circulation process, is burnt which helps to heat the roaster.

Does the design work?

 Below is a photo of the tubing that guides the re-circulated air to the Roasting Chamber.  The roaster was in service for 5 years before this photo was taken.  It had roasted about 30 tonnes of coffee.  It does illustrate why Fresh Cup Roastery Café (Saanichton & Vancouver) clients refer to it as  "Clean Air Roasting"

 Now compare the above photo with one taken of a drum roaster after one year of service.

There wasn't a copyright on the photo but I am not attributing the photo because there is little benefit to kicking a hornet's nest.

In 2010, it is reported that there were 1800 chimney fires, in the USA, that were attributed to coffee roasters.  What heating method do you think was responsible for this incredible statistic?












                                                ------------------------------------------
In the Roastaire the exhaust is passed through a second SmokEater© before it is discharged.  It roasted hundreds of batches inside the Toronto and Vancouver convention centres without the use of a vent or chimney.

What is exhausted?
 Only the air cooling the roasted coffee is exhausted after scrubbing it twice.  More details about the design reasoning will be forthcoming when the topic of Bean Cooling is approached.  In the interim here is some more information on an earlier NXT    blogspot page.

Off the Shelf Machines

My perception is that most companies are buying off the shelf devices which were built without their input.  In other words they are saddled with the compromises without having the opportunity of prioritizing them.  Buying a known technology does defer to the manufacturing company goals rather than to those of the end user.  Of course the manufacturing company wants their clients to succeed but the manufacturer's survival is viewed as being way more important.

Certainly we have purchased off the shelf technology but the moment we took possession of it the discussion began on improving the device to meet our needs.  Control systems were bypassed in favour of Labview based data acquisition and controls.  The equipment claims were compared to the measured performance then we searched for better and more effective ways to enhance the process.

Sometimes we contacted the evaluated equipment's manufacturer to test the waters about incorporating what we considered to be improvements while at other times we either kept the results in house or dropped the project in favour of a fresh approach.

It is possible to learn by analyzing existing machines.  Rarely will they prove to be an ideal fit to your needs but if you are attentive in its usage you will make up a list of Pros & Cons.  That conclusion will at least give you concepts to analyze and sometimes an appreciation for the work that went into the original design.  Falling into the trap of flippant analysis often leads in the wrong direction because it fails to take into consideration the battles of formulating the original design which after all usually achieved commercial status.  "Armchair quarterbacks" are known for their 20/20 hindsight  vision which does not make room for the Law of Unintended Consequences or even a thoughtful analysis.  Having said that sometimes a fresh look does provide insight because the person is not constrained by the history of the project or the emotional aspect of the design.

Modifying machines can mean living with the Law of Unintended Consequences especially in complex systems where there is interaction between many elements.  I think of it as the battle of the laws of physics which can be predictable or result in a complete surprise that should be explored or abandoned.  Abandoned projects can be revived when new techniques or solutions are found but until that moment manifests itself they are on the back burner if not in the deep freeze so to say.

Concluding now, for the sake of brevity, first; formulate an analysis plan by listing the requirements in order of priority, second; decide on the evaluation criterea, third; pay hommage to Genrikh Altshuller and examine patents to understand how others might have tackled the problem, fourth; undertake the challenge of melding the many ideas into a workable solution so that you can build your prototype.

NXT Freshly Roasted Coffee vs Marketing Spin

There are a lot of excuses that are generated by the untimely delivery of coffee.  It appears that more effort is made to make up a fanciful story than to deliver freshly roasted coffee.

It is easier to examine process where companies will pronounce certain rules as if they were laws rather than an opinion or marketing ploy.  Grocery stores have convinced the government agencies that coffee is not a perishable or that its shelf life is greater than 18 months.  Why?  I would say that it fits in with their warehousing distribution model rather than their concern for delivering a fresh product.  The economy brand coffee purveyors notably dance around their weakness which is usually centered on freshness.  Most often there is a clash of goals between their purchasing based on price and their desire to sell at a high end price.  Obviously that is not the message they wish to convey so this is where the marketing dance is conjured.
The question "Is your coffee freshly roasted"?  The typical answers:
- we grind it just before brewing
- we brew on the hour
- we serve our coffee when it is at its prime
- our coffee is ground to a different level
- we have a special relationship with our roaster even if it is 500 miles away
- our roaster uses the best beans
In all cases the question is not answered because it is important to circumvent that limitation by presenting a subjective answer (usually missing the point of the question).  It is a chink in their armour that appears to only be visible to those who are passionate about coffee, inquisitive about the claims, and discriminating purchasers.

On that note, a client must judge if coffee beans must degas for one to 5 days.  The beans will degas regardless because the pressure is sufficient to burst a tightly sealed plastic bag.  I prefer to package ASAP after roasting, letting the beans degas in the bag.  To that end we keep the bags closed, but not sealed, and upright so that the carbon dioxide* (which is more dense and heavier than air) will displace the air by pushing it our the top of the bag.  The client is able to decide when to drink the freshly roasted coffee. We have not found a need for valves.  If the valve is kept as the highest point of the bag the interstitial spaces will also be occupied by carbon dioxide instead of oxygen rich air.

Unfortunately most valves are located around the mid-line which means only half of the bag is purged of oxygen.  To purge the air from the valve equipped bag the bag has to be laid down so that the valve is the highest point in the bag.  Emptying the bag requires the same consideration to preserve the CO2 level, while keeping the bag upright scoop out the beans rather than pouring out the beans along with the CO2.  Pouring the entire bag into the grinder will pour in the CO2 as well but I suspect that the CO2 will drain out the bottom of the hopper, through the burrs, and out of the grinder.  That illustrates a grinder limitation which should be examined in another post.

*  Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom double bonded to two oxygen atoms.  Dry ice is the solid version of CO2.  The wafted vapour that we see above the dry ice exposed to room air is actually moisture from the air that has condensed due to the low temperature near the dry ice.

Improving the Roasting Efficiency.

There are several aspects to be considered before a process can be implemented to improve a design.   Often it is possible to identify, let's say for the sake of discussion, 10 variables that will affect the process.  What is usually impossible to predict is the rank or the level of dominance of each variable unless you are really really really a gifted analyzer or clairvoyant.  Personally I resort to testing a few variables at a time to better understand their effect.  There will undoubtedly be surprises and inconsistencies when various variables are tested together but it is simpler to test in parts than in whole.

The testing results are unlikely to produce a clear graph such are joys of solving problems with multiple unknowns.  The results will give a better idea about the trade-offs that are required before a process can be adopted.  We maintained that coffee beans should be uniformly heated so that the chemical reactions that occur within the beans progress evenly.  It was also deemed important that the beans not be thermally overloaded.  To clarify; the bean has a certain capacity to transmit heat to its interior, if the heat applied is greater than what can be evenly distributed the exterior surface becomes much hotter  and creates a risk of scorching.  It is also for this reason that we roast at a relatively lower temperatures of 240°C to 250°C instead of ...  In "Espresso Coffee" R. Eggers writes the typical gas temperature of a drum roaster is 400° - 550°C.  The high temperature cooking analogy for beans hit by the super hot air is frying eggs while using the stoves highest heat setting.  Yet this fluidized bed roaster has a cycle time of less than 12 minutes versus up to 20 minutes in a drum roaster.   That  is Better Efficiency! 

The even distribution of heat is critical to preparing the beans for the roasting process.  We force heated air between the beans so that they are all heated, not just the outside layer.  There are small domestic roasters that also use air to create a fountain of beans.  It is quite dramatic but if the air flows through a narrow passageway then the remaining beans are not being heated until they gradually make it to the fountain.  Consequently, if you are looking for a home roaster look for one that pushes the air through all the beans.  Typically, the batch will move upwards as the beans are levitated by the flowing air then the air will break through and mix the beans.  The release of air pressure allows them to drop within the chamber but are then suspended again.  The air cushion has the added advantage of keeping the beans off the hot metal which often causes tipping which appear as little pieces of the exterior wall that leave behind a shallow cavity.

It is a simple concept that is regulated by many variables which turn it into a complex process.  

There is more to the efficiency quest than even thermal transfer and the recycling of air mentioned in the previous blog which leaves something to write about later.  Now it is time for an espresso.

Updating our Roastery

We updated our Roastery and reception area so that it would not be confused with the workshop.



It is slightly more pleasant to sit down at a Granite table for the morning Espresso than a work bench.  Well, there is the optional bar height table for the devotees of the fitness club.

The main goal is to show that our roaster does not require a lot of room.   There is a full glass door that encourages observation though a full glass wall would yield a better view of the Roasting Theatre.

The coffee roaster is the focal point and the "raison d'être".  The green beans are loaded into the counter height Bean Loader Hopper.  the design of which expresses our opinion about overhead bean loading.  After roasting the beans are pneumatically conveyed to the Packaging area which saves the Roast Master from picking up roasted coffee from the floor area.  It appears that drum roaster designers just do not think of ergonomics and Roast Master comfort. These are important considerations when the Roast Master does sessions of over 20 roasts.

The previous post has some pictures of some of our morning Espresso shots.  Not all shots are photographed since pictures are secondary to tasting.  That series of pictures were intended to illustrate the Crema obtained with Freshly Roasted coffee.

The Coffee Roaster is labelled "Roastaire" which is the distributor for NXT Roasters in Canada.  Check out their site for information about roasting, energy conversion efficiency, and roasting pollution controls.

 

This is Crema !

Crema !!
There are few "honest" ways to get great Crema.  The first one is Freshly Roasted Coffee in a tuned Espresso Machine.  Of course that is also how you maximize the sweetness of high quality Arabica beans.

The quantity of Crema rapidly decreases as the roasted coffee ages.  The taste is also greatly affected by the staling that begins to make itself noticeable within one week after roasting.

In the first two pictures the Arabica beans were roasted four days previously.

The crema to liquid coffee conversion starts towards the end of the brewing process it is not so fast that the client would be deprived of a significant amount of Crema.

Crema has been viewed by many as an indicator of freshness.  Unfortunately some people think that it is clever to deliver Crema without the freshness.  Common techniques are to add chemical foamers or to add Robusta beans to a blend of Arabica beans because the Robusta beans yield a greater amount of Crema even when it is stale.  At one time the Robusta beans were considerably cheaper but the price increased when too many people started to add Robusta to the Arabica beans.   Adding bitterness for the sake of looks is not a good trade - for the client.  

Though it is possible for anyone to add Robusta beans it is less likely when a roaster is serving freshly roasted coffee, because their brew will naturally have the great indicator of freshness.  After all, a local roaster does not have a long supply chain which requires months to complete the distribution process.

Do yourself a great "flavour" by sourcing beans from a local roaster or someone who can deliver them within 2-3 days from the roasting date.

The brew in this French Press was prepared two days after Roasting.  It is also significant that the beans were ground with a blade type grinder which yields a coarser ground that yields  impressive results but is inconvenient because water will have to be added and the particles take longer to decant.  If the Plunger is pushed too quickly the Screen will plug and a hydraulic lock will occur.                                                        

A burr style grinder yields finer and more consistent results.  The finer grounds will infuse more quickly and will decant reasonably quickly.  The screen is then pushed down to prevent the grounds from being poured into the cup.  The solids do not add to the pleasant experience.                                   

Develop a personal coffee ceremony to consistently get great results.  If the results are not the best then try one thing differently and note if it is better or worse.

Hopefully there will be many improvements because well prepared freshly roasted coffee is so sublime.

 

 

The Roastaire™ visits Canadian Coffee & Tea Show

The Roastaire™ was the only functioning coffee roaster at the Canadian Coffee & Tea Show in Toronto.

The booth was near the Canadian Barista Championships but we were so busy that it was impossible to attend the skill demonstrations.

The Roastaire™ booth was designed to emulate the look of a Roastaire, coffee roaster, in a roastery café.  This layout favours the Theatre of Roasting which invites clients to observe the roasting process.  The clientele is able to pose questions to the Roastmaster without having the liability of having someone brush against hot surfaces.

 

The "roast is arrested" in the Roasting Chamber within seconds then is pneumatically conveyed to the Packaging Area where the beans are cooled for an additional three minutes while the Roastaire™ roasts another batch of beans.

In the picture below Mel, the Roastmaster, is removing the roasted beans from the Cooling Hopper (usually located in the packaging area).  The beans are cooled while another batch is roasting.  Many people dropped in to view the only functioning Coffee Roaster at the Coffee & Tea Show.

So very close now to a Freshly Roasted cup of coffee.

 The tiff to jpg conversion is off which emulates working before enjoying a Freshly Roasted cup of coffee.

After a Freshly Roasted cup of coffee everything just works better.   Even technology is receptive!

The Canadian Coffee & Tea Show

Well we are on our way to The Canadian Coffee & Tea Show in Toronto.

The trailer was packed with the Roastaire and the booth earlier in the week.  We expect to be roasting 3 kg batches in the conference hall without a chimney.  We did this at two earlier Canadian Coffee & Tea Shows in Toronto and Vancouver therefore it is not a new experience.  No other roaster appears to have the pollution controls to attempt this.

It will be a rather hectic event with many seminars, presentations, and discussions therefore there will most likely only be a recap after the show.  Perhaps Roastaire will be updating their blog during the event .

Does Extreme Processing Enhance Food visually or nutritionally ?

AKA - Does Processing make it a Lesser Food ?

There is an older blog that has largely gone unread, yet this is a very important topic that affects every ones health.  Is it a lack of interest, poor title, or is it not showing up in the Search Engines ?

The distilled opinion is "the more you process the less the consumer receives".

For various reasons the most common vehicle for food delivery has been perverted.  In response to "manufactured food", fresh food advocates are informing the public about  real food and real food costs.  My assumption is that to benefit from processing the end user must have the same objectives as the processor.  Very often they will share the visual objective but that is often irrelevant to nutrition if not detrimental.

Living on the 100-Mile Diet , Revisiting Carrying Capacity:, Natural Foods, Organic Foods, etc.  It appears that greater "inputs" yield less nutrition.  Large marketing budgets promote convenience and "filling the belly" instead of feeding the body for growth and health.  Increased time spent transporting food means, as well, increased food degradation time.  Industry will typically attempt to address product appearance indicators that influence a consumer.  Unfortunately nutrition is sacrificed for the sake of colour and appearance.  

Before focusing on one product not usually covered in the fresh food debates I would like to add that I believe that the movement advocating quality food is gaining membership.  

My interest is the freshness of coffee.  Of course people do not live by freshness of coffee alone.  That would be silly because it mostly feeds the soul, the well being, the disposition, etc.   Well there have been countless studies about the benefits ...   Coffee has undergone a centralizing process which exchanged convenience for quality.  Bigger is not better if the product is lessened.  We have not developed Star Trek transporters to move food instantly to the consumer while maintaining the product integrity.  If the past is any indicator this futuristic device would further degrade the food.  Warehousing roasted coffee decreases the value to the end user.

I advocate that the coffee roaster, grinder, espresso machine, and brewer should be at the same site.  Nothing gives more credibility to the freshness of the product as when the consumer can observe the preparation.  To this end Jim Townley uses the moniker of "the Theatre of Roasting".  It encourages clients to learn about the process while it reinforces the artisanal qualities of freshness and caring preparation.  Small batch roasting, in our case 3 kg batches, allows the RoastMaster to roast the requirements of the next few days.  Most likely more than one batch of each coffee will be roasted but that is a choice based on sales.

This is a simple food preparation model even though it appears to counter the produced locally mantra of some of the above links.  We are not blessed with local coffee plantations but because the coffee bean is a seed which is designed by nature for long term storage it may be consumed at a distance from its origins with a certain proviso.  So where is the Freshness Challenge?  Roasting transforms the bean and creates havoc with the storage capability of the bean.  Roasted Coffee degrades quickly despite touted storage "solutions".   Freshly ground stale beans is an advertising distraction which offers no benefit to the consumer.  The analogy of the weak chain link is true.  Nothing will resurrect stale coffee not even a marketing campaign.  

For the best cup of coffee start with a freshly roasted high mountain grown Arabica bean that is ground just before brewing.

Does Food Processing reduce nutrition ?

The distilled opinion is "the more you process the less the consumer receives".

For various reasons the most common vehicle for food delivery has been perverted.  Perhaps "Extra Virginity"  The Sublime and Scandalous World of Olive Oil by Tom Mueller shows that number cruncher executives care not a wit about their product, the well being of their customers, and sometimes the law.   People that are passionate about their product will bring the best to the customers sometimes at a great sacrifice.

Reuters had an article, a few days ago, to this effect: ...Coffee roasters quietly pulled off a financial feat last year that went unnoticed by most customers: Adding a higher proportion of cheaper, lower-grade robusta to their grounds as the price of top-notch arabica beans surged...  Not only are the beans cheaper but Robusta creates substantial crema even when it is stale therefore it gives a visual indicator of freshness even when it is not.

In response to "manufactured food", fresh food advocates are informing the public about  real food and real food costs.  

Living on the 100-Mile Diet , Revisiting Carrying Capacity:, Natural Foods, Organic Foods, etc.  It appears that greater "inputs" yield less nutrition.  Large marketing budgets promote convenience and "filling the belly" instead of feeding the body for growth and health.  Increased time spent transporting food means, as well, increased food degradation time.  Industry will typically attempt to address product appearance indicators that influence a consumer.  Unfortunately nutrition is sacrificed for the sake of colour and appearance.  

Before focusing on one product not usually covered in the fresh food debates I would like to add that I believe that the movement advocating quality food is gaining membership.  

My interest is the freshness of coffee.  Of course people do not live by freshness of coffee alone.  That would be silly because it mostly feeds the soul, the well being, the disposition, etc. Coffee has undergone a centralizing process which exchanged convenience for quality.  Bigger is not better if the product is lessened.  We have not developed Star Trek transporters to move food instantly to the consumer while maintaining the product integrity.  If the past is any indicator this futuristic device would further degrade the food.  Warehousing roasted coffee decreases the value to the end user.

I advocate that the coffee roaster, grinder, espresso machine, and brewer should be at the same site.  Nothing gives more credibility to the freshness of the product as when the consumer can observe the preparation.  To this end Jim Townley uses the moniker of "the Theatre of Roasting".  It encourages clients to learn about the process while it reinforces the artisanal qualities of freshness and caring preparation.  Small batch roasting, in our case 2 to 3 kg batches, allows the RoastMaster to roast the requirements of the next few days.  Most likely more than one batch of each coffee will be roasted but that is a choice based on sales.

This is a simple food preparation model even though it appears to counter the produced locally mantra of some of the above links.  We are not blessed with local coffee plantations but because the coffee bean is a seed which is designed by nature for long term storage it may be consumed at a distance from its origins with a certain proviso.  So where is the Freshness Challenge?  Roasting transforms the bean and creates havoc with the storage capability of the bean.  Roasted Coffee degrades quickly despite touted storage "solutions".   Freshly ground stale beans is an advertising distraction which offers no benefit to the consumer.  The analogy of the weak chain link is true.  Nothing will resurrect stale coffee, not milk, not sugar, not artificial liquids, not even a marketing campaign.  

For the best cup of coffee start with a freshly roasted high mountain grown Arabica bean that is ground just before brewing.

Carbon reduction or is it just "horse trading"*

There is even more to the story !

The unfortunate part about marketing claims vs. true development and technical improvements is that the marketing claims focus on changing perception rather improving the equipment.  It is the easy way out which in this case does nothing for the local air quality if someone planted trees hundreds of kilometres away.  The article cited does not mention that it took a decade to reduce the Roastaire™ emissions to a small fraction of conventional roasters.  In the process the energy required to roast was reduced to about 1/6 of a conventional coffee roaster.

The Roastaire™ was designed for the Café environment where people can observe the roasting process.  We refer to that as the "theatre of roasting".  The roaster is a compact unit that includes Chaff Cyclone, SmokEater™ (pollution controls), Pneumatic Bean Conveyor, and a Packaging Silo.  The roaster is approximately 6.5 feet high.  The roaster is controlled by a computer based Roast Monitor which  also configures the roaster, through the use of pneumatic valves, for the various modes in the roasting process.

More information is given in the post "Sustainable Design Follows Function"  such as the attention given to ergonomics.  An obvious example is the placement of the Loading Hopper which is placed at counter height rather than above the RoastMasters head.  The roasted beans are quickly cooled internally so that the smoke can be neutralized before it is vented.  The aim has been to improve and streamline the roasting session.  Cooling with a sustained blast of cool air within the Roasting Chamber means that the RoastMaster does not need to compensate for the roasting that takes place between the time of the decision and the moment that the beans are lowered below their combustion point.  The sum of the drum RoastMaster's reaction time, Roasting Chamber evacuation time, plus the actual time it takes to sufficiently cool the beans to stop the roasting process means that the RoastMaster must anticipate the final roast a minute or more in advance.  In drum roasting the process is analogous to "duck hunting";  if the hunter aims for the duck they will miss.  The hunter must shoot ahead of the duck by a distance that varies with variables such as height and speed of the duck.   Similarly skill and much training is required to anticipate the time required to get the correct drum roast.  The drum concept does not make it easier for the RoastMaster but that analysis will have to wait.

To help improve the efficiency of the Roastery the roasted beans are pneumatically conveyed to the packaging area where they can be weighed and placed directly in the bins. 

The Packaging Hopper can be mounted to the wall or placed on a table or counter.  It can be placed directly over the scale if the RoastMaster finds it more convenient.

Café owners that buy roasted beans see " FRESH Coffee! " post are simply paying for someone else's roaster without getting all the benefits.




* Horse trading is an idiom used to describe negotiations, especially where these are difficult and involve a lot of compromise.

Packaging - Optimism

Packaging attempts to circumvent or overcome the stalling of coffee.   It does not keep old coffee fresh though it is claimed that it slows down the staling for an unbelievably long time.  Most of the advantages are perceived by the consumer based on sizeable advertising programs.  Though it appears that a valve, at least under ideal conditions, lets little air into the bag.  Well, less than the bag would have had when it was sealed.  Vacuum sealing reduces the air and moisture in the bags but that requires more equipment and time.  The valve does let out the CO2 but it also lets the aroma escape.  The vented bag will have a lower internal pressure, than say a metal container.  The lower pressure exacerbates the loss of volatile compounds which are the reason for that olfactory experience.  To circumvent that loss some companies replace the vent by Oxygen and/or CO2 scavengers.

"Espresso Coffee" by Illy & Viani states that the spoilage rate increases by 7 fold with every 10°C increase in temperature.  Unfortunately there is no mention if that calculation starts at absolute zero. It is an unmeasured and uncontrolled variable that very much affects the coffee experience.

A lot of money was invested into the marketing of various types of packages because the business model of central roasters depends on convincing customers that coffee that is more than a year old still has the freshness of yesterday's roast.

I view the valve as a packaging solution which does not contribute much to maintaining the roasted bean's fresh taste.  My only acceptable solution is to buy the freshest coffee from a local roaster.  An exception, in Canada, is Freshcup.ca which ships, via expedited post, the day the coffee is roasted.  On several occasions I have sent some much appreciated coffee gifts.  It could be perceived that I am biased because they use our roaster though I maintain that the long relationship has allowed me to observe closely the organization and witness their commitment to delivering the freshest great tasting organic coffee to their customers.

Heating Coffee Beans to Roasting Temperature

In cooking the heating process is usually prescribed by the recipe.  Yet, there are reasons why certain chemical reactions are promoted by heating method and temperature.  Common sense tells us that a Blow Torch is not a good heat source for warming the body.  The high temperature differential means that the outside layer will burn before the inside is warm.  Perhaps the Blow Torch salesman would suggest that the body whirl like a Dervish near the flame to distribute the heat.


In "Espresso Coffee" R. Eggers writes the typical gas temperature of a drum roaster is 400° - 550°C.  The high temperature cooking analogy for beans hit by the super hot air is frying eggs while using the stoves highest heat setting.   To this end the Roastaire uses a fluidized bed in which 240°C (adjustable as required) air is pushed through the beans.  This significantly increases the heat transferred to the entire batch of beans.  The beans have a limited ability to absorb the heat therefore the temperature gradient is more uniform throughout the batch with the forced air stream.  The added benefit is that the air flow continually churns the beans and carries away the chaff.


Considerable research has been done to understand the dynamic and continually evolving variables in the coffee roasting process.  In the design phase, of the Roaster, the limitations of the bean and the requirements to start the chemical reaction, referred to as roasting, determine the roasting precepts.  We do not believe in using extreme 400°C plus air  temperature that mostly moves around the batch of beans.  The beans will burn on the outside before it is hot inside.  Agreed the beans are in motion and only subjected to intermittent burning temperatures.  The average may be arithmetically acceptable but then so is keeping half your body in ice while the other half is in boiling water.  Perhaps some manufacturers slavishly follow this century old trend because it is easy and obvious.   


The starting point of the exothermic reaction ( above 180°C according to R.Eggers and at 200°C according to Clarke & Macrae).  We commonly use an air temperature of 240°C delivered under pressure so that the air is forced through the batch without initially losing more than a few tens of degrees.  The heat transfer to the beans, is slightly higher at the beginning of the roast when the beans are denser and able to transmit more heat internally.  Initially the heat absorbed serves to evaporate the moisture which determines the heat slope (how quickly the beans increase in temperature).  The decrease in bean density reduces the heat absorption by the beans hence the air temperature is rather uniform for the first and last layers.  Actually when the exothermic reaction begins the heat generated in the first layers raises the temperature of the beans that are down stream.   Delivering the air with sufficient pressure at 240°C is a challenge that will be addressed in a later post.  Sufficient to say that no off the shelf hot air blowers were found, resulting in another product development.


The Blower's pressurized air heats the beans and mixes them with a "bubble action" which helps reduce the contact of beans and the hot metal sides of the Roasting Chamber.  Some home roasters tout the advantage of their fountain mixing of the beans which is not optimal for roasting.  A fountain is created when the air flow is concentrated in one area which means that the air is not flowing through the rest of the beans i.e. not heating them evenly.


Time for a freshly roasted coffee.  Agree?

Food Processing vs. Nutrition ?

AKA - Does Processing make it a Lesser Food ?

The distilled opinion is "the more you process the less the consumer receives".

For various reasons the most common vehicle for food delivery has been perverted.  In response to "manufactured food", fresh food advocates are informing the public about  real food and real food costs.  

Living on the 100-Mile Diet , Revisiting Carrying Capacity:, Natural Foods, Organic Foods, etc.  It appears that greater "inputs" yield less nutrition.  Large marketing budgets promote convenience and "filling the belly" instead of feeding the body for growth and health.  Increased time spent transporting food means, as well, increased food degradation time.  Industry will typically attempt to address product appearance indicators that influence a consumer.  Unfortunately nutrition is sacrificed for the sake of colour and appearance.  

Before focusing on one product not usually covered in the fresh food debates I would like to add that I believe that the movement advocating quality food is gaining membership.  

My interest is the freshness of coffee.  Of course people do not live by freshness of coffee alone.  That would be silly because it mostly feeds the soul, the well being, the disposition, etc. Coffee has undergone a centralizing process which exchanged convenience for quality.  Bigger is not better if the product is lessened.  We have not developed Star Trek transporters to move food instantly to the consumer while maintaining the product integrity.  If the past is any indicator this futuristic device would further degrade the food.  Warehousing roasted coffee decreases the value to the end user.

I advocate that the coffee roaster, grinder, espresso machine, and brewer should be at the same site.  Nothing gives more credibility to the freshness of the product as when the consumer can observe the preparation.  To this end Jim Townley uses the moniker of "the Theatre of Roasting".  It encourages clients to learn about the process while it reinforces the artisanal qualities of freshness and caring preparation.  Small batch roasting, in our case 3 kg batches, allows the RoastMaster to roast the requirements of the next few days.  Most likely more than one batch of each coffee will be roasted but that is a choice based on sales.

This is a simple food preparation model even though it appears to counter the produced locally mantra of some of the above links.  We are not blessed with local coffee plantations but because the coffee bean is a seed which is designed by nature for long term storage it may be consumed at a distance from its origins with a certain proviso.  So where is the Freshness Challenge?  Roasting transforms the bean and creates havoc with the storage capability of the bean.  Roasted Coffee degrades quickly despite touted storage "solutions".   Freshly ground stale beans is an advertising distraction which offers no benefit to the consumer.  The analogy of the weak chain link is true.  Nothing will resurrect stale coffee not even a marketing campaign.  

For the best cup of coffee start with a freshly roasted high mountain grown Arabica bean that is ground just before brewing.

Staling of Roasted Coffee

Coffee stales much faster than it is commonly perceived.  An extreme example is noted in "Coffee Technology"by Michael Sivetz where he mentions that moisture absorption from the air or due to water quenching need only to be 1% to noticeably stale coffee within the hour.  This represents 30 cc (1 fluid ounce ) per 3 kg ( 6.6 lb ) batch which,  considering that the beans lost 12 to 20 times that much moisture when roasting, is quite significant.  Advocates of water quenching claim that all the water evaporates as it hits the bean.  I am not so certain that this is so because after roasting the bean is very porous which means that the water will quickly cool the outside layer the bean will then have difficulty conducting the heat to the surface to evaporate 100% of the moisture.  The increased porosity will help draw the moisture inside.

Each opening of the container allows more moist air to reach the roasted coffee.   Sivetz writes that the beans are "moderately stale" within a week, more stale within two weeks and stale in three weeks.  Greater surface area i.e. ground beans significantly increases the absorption of air and moisture.

Vacuum packaging does remove most of the air but if it is done within a few hours of roasting it can create problems because of the high pressure CO2 will be released from the beans and inflate the bag.  If the coffee is ground the CO2 will be mostly released within the hour.

In theory the Valve on the Bag permits a longer storage time but I am sceptical about that valve working perfectly.  The changes in air pressure are small and applied over long periods of time as the barometric pressure changes which causes the bag to breathe.  The valves are attached to a bag that is filled with coffee beans which is not a flat surface hence I am thinking that it leaks and that it's purpose is to prevent the bag from bursting from C02 pressure.  Before going further that has to be tested.  I reiterate that the only safe bet is buy Freshly Roasted coffee.

FRESHLY Roasted Coffee!

FRESHNESS is a contentious topic.  Groups that can't provide fresh coffee because of their long supply chain attempt to ignore this essential factor when selling a perishable food.  Cafés that Roast OnSite say that coffee staling begins to be noticeable one week after roasting.  They aim to sell "take home coffee beans" within the week and to serve all coffee within 1 1/2 weeks.  The question they ask is "Would you buy 10 day old bread?".  We attempt to bolster this strategy by providing an efficient small batch 3 kg roaster which makes it easy for the café to roast only the coffee beans that are required for the next few days.  This roaster benefits from the advantages of using electric heating which allows the re-circulation of the heated air after it is scrubbed of the smoke particles.  The built-in SmokEater™breaks down the exhaust gasses which otherwise cause neighbours to complain about roasting odours.

Café owners that buy from a local roaster sometimes do have fresh coffee but, obviously, they can't proudly serve their own creation.  The passion of creation communicates very well at the counter.  Perhaps they do not really know when the coffee beans were roasted.  One RoastMaster explained it like this: we put it for sale as an estate arabica, after some time we make blends, and if we still have some left we wet a cloth with some flavouring and tumble it and the beans in a small drum.  Is that flavouring to enhance or mask?  To the Café owner "Does the cost of your coffee pay for your roaster or your supplier's?"

A lot of lobbying dollars were spent to convince governments that coffee beans last more than 18 months therefore did not require expiry dates, in other words they concluded that roasted beans were non perishable.  This decision was required by centralized roasters and grocery chains because they cannot transport the beans to client coffee pots within two weeks.  Consequently, they promote peripheral messages such as freshly ground, freshly brewed, consistency, convenience, low price, contests, etc.   They can accessorize the product as much as they want but if you start with stale beans you can't make a quality drink.  Coffee parallels the preparation of food in that increased processing equals diminished quality.  Some of the tricks are to add cheaper robusta beans, which are more bitter than arabica beans, to the blend so that the espresso will have more crema like freshly roasted coffee.  It is not a great espresso and most likely they will suggest that you give it some zing with a flavouring.  Freshly roasted coffee has plenty of zing plus it has complexity that a flavouring does not even try to achieve.

Out of curiosity two books were consulted; one by a large Italian central roaster and other by UK specialists.  The first only mentions "freshness" as it pertains to serving it quickly after it is brewed.  The second book does not mention freshness.  Freshness is not part of the centralized roasting business model.  As a consumer the choice is yours "Do you wish to pay for freshness or warehousing?".

Packaging is often ascribed miracle properties.  In the first day(s) following roasting the beans emit a lot of carbon dioxide which can burst bags.  Hence, the use of the valve.  If the valve is the highest point in the bag the CO2 will force out the lighter gases such as air which is beneficial but it is hardly locking the flavour in.  One web site says that packaged coffee lasts a few months until the bag is opened but a little further down they claim: How long does coffee last? Coffee packaged with a freshness valve = 12 months then add a little further Ground coffee once the bag is opened = 2 weeks.  Check for consistency of message and verify that information.  Your priority is taste or the coffee experience theirs is sales.  Studies have been done about slowing down the degradation through cold storage but that requires colder deep freezers than those in homes.  An additional problem is that, due to the pressure differential, the deep freeze is the area with the highest humidity in a house.  Moisture accelerates staleness.

If possible observe a roasting session, you will learn.  You may find that some of the urban based coffee roasters are not used because of pollution complaints and that some RoastMasters , that do not have Afterburners, roast during the night. 

To improve the roasted beans' relatively short lifespan they should be ground just before brewing.  Make a comparison with beans that have been ground for half an hour. I expect that after half an hour the finely ground beans will make a flat coffee.  An espresso will have greatly reduced crema.  You will then be in a position to judge the statement "Ground coffee once the bag is opened = 2 weeks"

My mantra is "Buy from the roaster".

Sustainable Design Follows Function

In the Generation 1 the Roastmaster had to lift the beans over his head to fill the Loading Hopper.  Not surprisingly it was not the popular choice but it was the simplest solution.  The Roasting Chamber was pivoted from the Loading/Roasting position to the Dump position where the roasted coffee was dropped into a Cooling Tray.   The SmokEater™ (an efficient form of the After-burner used gas heated roasters) was attached but not an integral part of the machine.   Maintaining seal integrity on the sliding Roast Chamber was difficult and was exacerbated by the strong smoke of the dark roasts.

Generation 2 went through several iterations.  It did away with the sliding Roasting Chamber and overhead Loading Hopper.  The counter top roaster, again with an outboard SmokEater™ had pneumatically controlled valves which were able to route the air so that green beans could be loaded from a counter height Loading Hopper. The re-circulated pressurized air is able to transfer more heat evenly to the beans than the high temperature (often twice the temperature)- low pressure circulated air used in drum roasters because in the fluidized bed all the air goes through the beans without having a portion of the flow simply going around the beans.  This model also introduced the second generation of the Roasting Monitor.

The function of the NXT Roaster is responsible for the form it was given.  In brief, recirculation requires the shape of an "O" which is formed by the two larger columns tied together by the base and top pipes.  The left most small rear column is the Cyclone which removes the chaff from the circulating air while the right most  rear column is the SmokEater™which does the final air cleaning or smoke neutralizing before exhausting the air during the Cool Mode.

Shown above is the third generation 3 kg Roastaire™ that roasted on the exhibition floor at both the Toronto and the Vancouver Canadian Coffee & Tea Shows.  No chimney was used for the 110 batches of green beans roasted.  It was the only roaster that Roasted On-Site and inside the hall.   This version was a "complete re-think" of the functions and the layout of the coffee roaster.  It required the development of a High Temperature Blower capable of fluidizing the green beans, a new computer based Roasting Monitor, PID Temperature Controllers, two Pneumatic Bean Conveyors, initial bean cooling within the Roasting Chamber, and a Packaging Silo to further cool the roasted coffee beans.  The SmokEater™ was incorporated into the Roaster body so that the entire unit could be moved on casters and occupy a relatively small footprint.

The goal was to make the industrial roaster compatible with an urban environment, without requiring optional add-ons, yet be as compact as possible.  To improve the efficiency well above that of a gas burning roaster the air was recirculated.  The post "Roaster Pollution Reduction" shows photographic results, after 5 years of cafe roasting, that the air was cleaned before it was re-circulated to the Roasting Chamber.   This compares very well with the caked exhausts, of other roasters, shown by KaladiCoffee on Youtube.com .  It was not an overnight success but it works well.  The High Temperature Blower required a great deal of development since off the shelf blowers do not survive such temperatures for very long even with high priced precision bearings.  The pressure and flow is required to fluidize the beans which is among the most efficient ways to evenly transfer the heat to the beans.  The wasteful solution has been to move cold air which is then passed through the Heating Element.  Air is continually heated from ambient to roasting temperature.  The wasted energy is augmented when the Pollution Controls are implemented. The NXT Roaster only exhausts air for 75 seconds of the 10 to 12 minute roasting cycle,  During this phase the air is further cleaned, as shown in another photo in the already mentioned post.

The Computer based Roasting Monitor makes it possible for the Roastmaster to monitor the pyrolytic process to consistently and repeatedly attain the required degree of roast.  There will be another post along with annotated pictures of the program's screen view in a further post or maybe posts.  The Roasting Monitor clearly shows the the pyrolytic reaction is stopped within seconds, minimizing the roasting overshoot which allows the Roastmaster to "call the roast" for its degree rather than for what it will be in 60 to 90 seconds. Which is the time some units take to dump the beans, fill the bottom of the Cooling Tray, then turn on the Cooling Fan.

The PID ( Proportional Integral Derivative ) Temperature Controllers do not click Off/On as the temperature passes through the set point but rather the algorithms analyze the rate of temperature change to anticipate, with accuracy, reaching the temperature set point.

The Loading Pneumatic Conveyor allows the Roastmaster to fill the counter height Loading Hopper with 3 kg of green beans rather than the too common overhead hopper.  The Green Bean loading takes place at the same time as the roasted coffee beans are conveyed to the Packaging Silo then cooled for several minutes.  Typically this silo is positioned in the packaging area above the counter, shown in a photo from the Canadian Coffee & Tea Show booth.

Fresh Cup Roastery Café booth   (well, half of the booth)

There is no visible exhaust to show how effectively the Pollution Control System is.  We have reached the level of requiring sniffers and gas analyzers.  The electric elements obviously do not create combustion gases which, in gas fired drum roasters, are circulated through the coffee before flowing to the chimney.  Afterburners, for gas fired drum roasters, with a comparable output to the Roastaire™ range from 400,000 btu to 1 million btu which significantly increases the energy costs of each pound roasted.  Such a waste.  Perhaps an operational cost comparison blog is in the offing.