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?












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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.

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.

NXT Fluidized Bed Roaster

AT NXT ROASTERS INC. WE USE THE WORD “INNOVATIVE” AS DISTINCT FROM “IMITATIVE” TO DESCRIBE OUR APPROACH TO DESIGN.

 

The NXT Roaster Design

We selected the fluidized bed technology for our roasting process because it provides even heat distribution, which results in product uniformity. The bean chaff is continually removed from the roasting chamber, eliminating the fire potential. 

To increase roaster efficiency we re-circulate hot air, reducing power consumption by about 75 percent.  To prevent tar deposits on roasted beans (from circulated air), we incorporate a primary afterburner, which burns away the smoke every time the air is reheated.  This arrangement increases the temperature of circulating air, which further reduces overall power consumption.

By circulating hot air in the roaster, we are open to the atmosphere only thirty seconds at the end of the roasting cycle when hot coffee beans are quenched by a blast of cool air, which is vented through our “SmokEater”.  (As an option, we deliver a roasting system that can vent to a room/space.) Loading green beans and unloading of roasted beans is done pneumatically.

The Roasting Process

Roasting requires considerable control of the process to continually achieve a given degree of roast.  In any chemical engineering, operation controls address heat requirements, actual heat balances in roasting, and various heat transfer factors to determine the time required for roasting.   Many of the variables are beyond the control, of the Roast Master but it is possible to tame the process and reliably produce consistent roasts.

The NXT Roaster and its Roasting Process Controls include features that optimize process parameters such that the quality of roasted coffee delivered remains on target and is unaffected by factors beyond one’s control.

Roaster Description

The NXT Fluidized Bed 3 kg Roaster, is now in it's third generation.  The complete system comprises of: process controls, a primary after-burner, a SmokEater, Heating and Roasting Chambers, a chaff removal Cyclone and a pneumatic control system to operate the valves, which automatically load green beans, and transport roasted beans to the Packaging Silo at the end of the roasting process.

 Sequence of Operation

The Roasting Chamber is a cylindrical vessel that has at the chamber’s bottom a Butterfly Valve with Perforated Gate. Air enters the roasting chamber and simultaneously fluidizes and heats, or cools the coffee beans.  When roasting is finished, a blast of ambient air stops the pyrolysis by cooling the beans to below 150º C (320º F). When this temperature is reached, the Butterfly Valve opens and discharges roasted beans through the Poppet Valve and beans are then pneumatically transported to a Packaging Silo.

After-Burner System

The roaster is equipped with a primary after-burner and a secondary “SmokEater”.  The primary after-burner scrubs the hot air of volatiles and tar before these enter the Roasting Chamber.

The “SmokEater” is used at the end of the roasting process to scrub the smoke-laden cooling air from the roasted beans before it is vented to the atmosphere.

Comparing NXT Roaster roasteries with  and Drum Roasters 

		NXT    Roaster		Drum               Roaster
Batch capacity	kg	3		5
Hourly output	kg	18		14.7
Average time per batch	min	10		20
Power consumption with afterburners	kW/hour	6		64.5
Air required for roasting  process	CFM	80		300
Exhaust gas vented per batch	Cubic Feet	40		6000
Exhaust gas vented per hour	Cubic Feet	240		18000
Annual output
Roasting days per year	300	16200		13230
Roasting hours per day	3
Power consumption	kWh	5400		58050
Exhaust gas vented to atmosphere Annually	Cubic Feet	216,000		16,200,000

Improving Roasting Technology

The picture links were removed because Photobucket decided to change the terms of usage in mid stream, so to say,  It is inconvenient for viewers but it is better to rid yourself of such people as soon as possible.  It is the attitude as much as the action.   We will try to repair that mess at NXTroasters.com

 The conventional approach appears to be - buy a roaster and endure its limitations.  Most conventional roaster owners spend more time developing marketing spin than improving their coffee roaster.   The deficiencies i.e. emissions are already the focus of some legislative bodies which require permits for roasters in their jurisdictions.   Oil burning engines, showing that blue smoke, are rarely seen on the road today yet many owners are complacent about roasting without pollution controls.

The roaster owners who are concerned that large plumes of smoke coming from their chimney are bad for their community image have purchased large gas fired after-burners that burn approximately three times more gas than the roaster itself.  Imagine if automobile pollution controls involved using three times more gasoline than the engine.

Rather than maintain the polluting status quo which may or may not have visible smoke, NXT Roasters Inc., have developed an alternative (branded the Roastaire in Canada) approach that uses the smoke generated as a source of roasting heat rather than expend large amounts of additional energy to thermally neutralize the smoke.   Both 15 Kg/hour concepts thermally treat the pollutants but one system uses a 400,000 to 700,000 BTU after-burner  to accomplish the task.

The first picture is of the main air passageway of a Roastaire after five years of full time roasting.  This revealing photo demonstrates the reason for their motto of "Clean Air Roasting".  This illustrates how efficient and effective the air is scrubbed clean as it is re-circulated during the roasting process.   This closed loop roasting process means that the air only has to be heated 20° to 40°C to return it to the roasting temperature.  Compare that to a single pass air supply that is continually heated from ambient temperature then sent to the chimney.   In "Espresso Coffee" R. Eggers writes the typical gas temperature of a drum roaster is 400° - 550°C.   What a wasteful process.

In comparison,

one drum roasters Maintenance Manual draws attention to the chimney,  "Even if residue build-ups do not exceed 1/8 inch (.3 cm) per year, clean system annually ".    The quotation is not properly cited nor acknowledged but I will do so if the manufacturer requests it.

They also have this picture of a drum roaster fan as a warning about the residue that coats some of their components.  Roast Magazine had the following quotation "It's not IF you're going to have a roaster fire, but WHEN."  Which roaster do you think requires the most maintenance?  Which type of roaster do you think was responsible for nearly 1,800 chimney fires in the USA in 2010?

Which roaster do you think roasted hundreds of pounds of green beans inside the exhibition hall of the last four annual 

Canadian Coffee & Tea Shows?

Aeropress - Well Designed & Good Value

NXT Roasters has a Coffee and Aeropress bundle in limited quantities available at our Roastery.

The picture links were removed because Photobucket decided to change the terms of usage in mid stream, so to say,  It is inconvenient for viewers but it is better to rid yourself of such people as soon as possible.  It is the attitude as much as the action.

Freshly Roasted coffee enhances the Aeropress and vis versa.   This brewer does not require an electric brewer which may bring you better coffee since all decent kettles can boil water but not all electric brewers can deliver water at 90°C or higher.

The coffee is Freshly Roasted On-Site in a roaster of our design that has achieved new levels of consistency and pollution controls.  We are very proud of the taste.



 This is the Aeropress package which consists of the brewer and some handy accessories.  The previous blog links to two videos that demonstrate how to prepare coffee with this unit.

We have found that a fine grind enhances the extraction and quite likely gives you a better exercise.  It is difficult to establish if more calories are "burnt off" during the press.

There has been some controversy about paper filters versus perforated stainless steel discs in the domains of tasted and environment.  The stainless steel discs are nearly the price of the entire unit therefore we opted to make the bundle more affordable rather than a high end offer that would cause many to hesitate.

The coffee is less "strong" than an espresso but stronger than drip.  People adjust to their preference by adding water to the final brew and call it an Americano.

There is a challenge for those who appreciate the espresso because the Aeropress cannot be placed on a demi-tasse, well not yet.  Extracting a small volume into a large cup is not satisfactory so we must accept some limits.  However, before discounting the unit try what it does best which is a smaller cup of coffee.

Scoop:

The Scoop contains about 12 grams of coffee depending on how the coffee is scooped and packed.  The preparation of coffee depends more on consistency than an absolute number because other variables often compensate.  Just don't consistently use stale coffee - nothing compensates for that.

Funnel:
Might also be useful in the kitchen but in this case it helps assure that the caffeine deprived person gets most of the coffee grind inside the brewing chamber.

Stirrer:
This is used to be certain that the grind is dispersed in the hot water (remember the key word is hot).  The top has "wings" which prevent the blade from reaching the bottom and tearing the Paper Filter.  Of course this is a moot point when using the Inverted Method.



 Paper Filter:
This is placed inside the Cap to stop the sediment from reaching your cup.  The Paper Filter can be replaced by a stainless steel perforated disc for the people who feel that the paper absorbs essential oils that rightfully should be in their cup.















                          Brewing Chamber et al.:

                       Brewing Chamber                     Plunger                    Filter Cap                    Paper Filter

Inverted style brewing: This is mentioned first because everyone reads the instructions which illustrate the conventional way of using the brewer.

 Place the Plunger inside the Brewing Chamber. 

The internal volume increases approximately 60cc for every number the Plunger is pulled down. Therefore for those without a calculator:
- 60cc X 4 units X .03519 = 8.4 Canadian ounces
- 60cc X 4 units X .03381 = 8.1 US ounces

Unless you know all about compensating for the meniscus let's call it 8 ounces no matter where you live is the maximum capacity.

For a good Plunger seal keep both components vertical.  We cannot accept responsibility for spillage and "accidents" so we count on your diligence in keeping the hole towards the top.

Pour in the ground coffee without resting on the containers. Use one or two Scoops depending on the concentration your body requires.

Add the hot water without resting on the Brewing Chamber.

NOTE:  If there is unsteadiness or it is a challenge to manipulate these devices when they are full of scaldingly hot water you should resort to the conventional method.  Leave this method to the adventurous who thrive on danger.

Mix the water and coffee with the Stirrer to facilitate the extraction.

Place the Filter Paper in the Filter Cap (it will hold better if wet) and screw it to the top of the Brewing Chamber.  Hold the top of the Brewing Chamber.  Just remember the caveats - the liquid is very hot but bliss is now near.

Turn over the Aeropress and place it on a cup (please use a cup that is big enough for the contents). 

Push down on the Plunger.

It should now look something like the photo to the right.

Most people will now drink the coffee before extruding the Coffee Puck which is visible after removing the Filter Cap.

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 .

The Importance of Timely Bean Cooling

Coffee is roasted by way of an exothermic reaction.  Without cooling, the beans would invariably burn because they reach the combustion point.   Roasting consistency can only be achieved through the timely introduction of the cooling air, which halts the roasting, to all the beans.

Drum roasting requires well developed skills because there is an extended lag between the moment the RoastMaster views the beans in the Bean Sampler and the termination of the exothermic reaction.  Several factors affect the degree of roast in a drum roaster; the air temperature is considerably higher than what is required for roasting  ("Espresso Coffee" R. Eggers writes the typical gas temperature of a drum roaster is 400° - 550°C. ), using a Bean Sampler is a relatively slow procedure, and the Cooling fans are relatively inefficient at moving air through several layers of beans.  Sucking the air downwards through the beans is also bad design because it packs beans together which greatly hinders air flow.  Many drum roasters spray water on the beans to cool them more quickly.  This is not good nor is it a measured cooling method.

The high temperature cooking analogy for beans hit by the super hot air is cooking Scrambled Eggs while using the stoves highest heat setting.   Even if they are continually mixed the heat is much higher than the egg can transmit to the interior.  The higher heat of the drum roaster still yields a relatively slow roast which highlights the inefficient transfer of energy.         For more details see "NOT Sustainable Roasting" and "Heating Coffee Beans to Roasting Temperature"

It is said that every second counts when "calling the roast" yet it takes many seconds to determine the degree of roast using a Bean Sampler especially if multiple readings have to be taken to follow the progression.

Many roasters are  stressed  by "calling the roast" even after they have been roasting for nine months.  The beans continue to roast during the dumping process and at the beginning of the air cooling cycle.  It is a common drum roasting technique that water is sprayed unto the beans to soak up heat.  It is impossible to accurately meter water coming from a garden hose.  Moisture is the #1 enemy of roasted coffee.  That lingering roast period means the drum RoastMaster must anticipate the roast quite a bit in advance of the required roast level.  An appropriate analogy is shooting ducks; the expert hunter aims for the position where the duck will be when the buckshot arrives.  The hunter must compensate for altitude, shell powder load, temperature, duck speed, and probably many other things that only a good hunter would know. For various reasons a lot of people have a problem with duck hunting (no ducks were harmed for this analogy).  The drum RoastMaster does not deal with less variables.

 To this end the NXT aka Roastaire uses a fluidized bed in which 240°C (adjustable as required) air is pushed, under pressure, 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.

 The beans are cooled within the Roasting Chamber therefore "calling the roast" is done in real time.  The blast of cooling air also churns the beans so that there is even and rapid cooling.  The Roast Monitor communicates to the RoastMaster the roasting progress so that the Cooling Cycle is started at the proper moment.  It only takes a few seconds to cool the beans ( below 180°C according to R.Eggers and below 200°C according to Clarke & Macrae) to stop the roasting process.  After this 30 second Cool Mode the beans are transported to the Packaging Hopper while the NXT aka Roastaire loads nother batch freeing the RoastMaster to appreciate a freshly roasted coffee.

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.

Roaster Carbon Calculations

The good people at Fresh Cup used the U.S. EPA Carbon Calculator to compare the Roastaire Carbon Footprint with that of a gas roaster.   

A 100 lbs.  of roasted coffee = 1 car off the road for 16 days  

This is how our roasting method impacts the environment. The energy ratio is  2 light bulbs versus the drum roasters 48 light bulbs.  Gas is a cheaper form of energy therefore in dollar terms the approximate heating cost of a gas fired roaster with afterburner is 16¢ per pound vs. the 2.5¢ for the recirculating Roastaire.


Evidently the Roastaire is way more environmentally friendly and cheaper to operate.  


The 100 lbs. of roasted beans represents about 3 hours of roasting, depending on the degree of roast.  Think of the savings to the environment and to the owner.  


It's time for a cup of freshly roasted coffee and a read about selling carbon credits.

No Carbon Credits Required !

November 1st, 2011 – Victoria, B.C.

Many coffee roasting companies across Canada claim 'carbon neutral' status these days, however, consumers are encouraged to look closely at their labels to find out 'how' they achieve this. Carbon credits are being bought by a number of roasting companies whose technology is outdated and continues to pollute the environment. Many companies are folding the costs of carbon credits into their cost of goods. 'If you look closely, many coffee companies are claiming carbon neutral status, but all they're doing is buying credits to offset their emissions', states Fresh Cup President, Jim Townley. 'The truth is, the consumer is likely paying a higher price for a product without even knowing it'. No matter how you slice buying carbon credits, they are a cost to any company and many companies are buying them more for their marketing value than the purpose that they were intended for. 'Whether you plant a tree, or buy credits to off-set the carbon emissions produced in making a product, it costs money', notes Townley. That cost has to show up somewhere along the line, and if the cost to buy credits is left low like it currently is, many companies will continue to pollute and make consumers pay the price. 'What's the point of low cost credits, if the cost can be added to the product for the consumer to pay ? Where's the motivation for companies to change their business practices to minimize the impact on the environment', asks Townley. 'Our approach is simple…be sustainable in how we roast coffee by reusing the heat, while drastically minimizing the emissions, then there's no carbon credits required'.

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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 above 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.

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

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".

"Green" Roaster

Pollution controls is a timely topic but it was not at all planned for right now, another example of serendipity.  We are currently upgrading Mel's ( freshcup.ca ) third generation Roastaire™.  It is only five years old but enough new parts were developed in the interim that it was a good idea to modify or install parts to satisfy his working requirements.  The first occasion for an "Ah Hah!" moment was the inside view of the exhaust just before it enters the chimney.   It was a good feeling to have the proof that the "SmokEater™" was working so well.

The second element in this synchronicity is the chimney fire warning contained in two advertisements in the September - October  "roast Magazine":

- If you're a roaster, you know the quote: "It's not IF you're going to have a roaster fire, but WHEN."

- "According to the U.S. Government, there were over 1,800 roaster fires last year." an advert by Iron Dragon Tools

They were advocating regular exhaust and chimney cleaning to prevent chimney fires yet the Roastaire™s roasted for over a decade without cleaning an exhaust nor having a problem.  Furthermore, only days before we had witnessed a five year old Roastaire™, which roasted 5 days a week,  that had an exhaust which was as clean as the day it was installed.

Further reading of "roast Magazine" showed the significance of the problem where their featured interviews asked each interviewee about their experience with fires.  Youtube has some videos of the chimney coating problems faced by other roasting companies.  Mel was deprived of this experience but he does not mind.

Originally our pollution test was only a visual inspection or rather the lack of visual evidence at the chimney when the Roastaire began the Cool Mode.  The test is more stringent now but we did not have to make any changes to the roaster.  Obviously a clear exhaust cannot be deemed to be a definitive pollution test after all we know that the common solution to neutralizing the smoke is to subject it to the high heat of a natural gas flame.  Small independent roasters do not have the required scrubbers to clean the combustion residues but they do eliminate the roasting smoke.  You still have to ask "Is the 400,000 btu to 1 million btu flame in the Afterburner the best way to eliminate smoke?".  It seems to be very wasteful to me not to mention the pollution by that flame itself.  In addition to its costly fuel charges the gas Afterburner takes up valuable floor space.  We decided to make the SmokEater™ a standard component of the roaster to optimize its operation and to minimize the footprint.  It does create a more expensive basic unit but we don't foster midnight roasting unless it is the third shift.  Of course not having to pay the gas heating for those high input Afterburners means that savings accrue very quickly.

Another fundamental difference with Drum Coffee Roasters is that they are continually flowing air through the flame, through the beans, and then up the chimney.  The Roastaire™ is a closed loop system for the entire Roast Mode.  During that time the air is recirculated which has the added benefit of significantly increasing the heating efficiency.  The air cleaning process wasn't an easy problem to solve.  Leaving too much smoke in the circulating air can affect the taste of the coffee by coating the beans with a tar like substance plus coating the inside of the roaster with the same substance.  Below is a photo of the air duct just before it enters the Roasting Chamber.  After 5 years of roasting there is only a light staining of the interior of the duct.

A design choice was to stop the roasting process within the roaster to improve the roasting repeatability.  Our earlier generations used a cooling tray, which is easier to accomplish, that delays cooling until the transfer is done and evenly distributed over the bottom.  Cooling within the Roasting Chamber permits the constant monitoring of the air quenching of the beans which stops the exothermic roasting reaction within a few seconds.   It also assures that the air entering the roaster during the Cool Mode will be "double cleaned" before it is evacuated to the vent or chimney.

California is the bellwether on emission standards but it is still a work in progress.  The traditional method has been complaint based forcing many roasters to occupy commercial areas or midnight roasting.  The people at Roastaire™ promote the "theatre of roasting" which takes place at the café.  It is the most convincing way of communicating to clients that the coffee is "freshly roasted".  To this end they roasted, without a chimney, on the floor of the Canadian Coffee & Tea Shows in Vancouver and last year in Toronto.  

In closing here is a quotation that appears in the October 26, 2011 edition of the Edmonton Journal Food Section which describes one side effect of the technologies we supersede.

“When we moved from our old location to this new location, the first couple of months we roasted coffee, I saw the fire department four times because people driving by would see all the smoke from the roaster coming out of the roof, and they thought the building was on fire,” says Filpula, laughing. “The firemen would come in; I’d give a tour of the roaster.”