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.
