Abstract wrote:Applying a statistical assessment of the results, we found the loss of most volatile compounds from all stored coffee samples, including even those stored under freezing
conditions.

This statement is misleadingly translated. Each packet lost a portion of all their aromatics, but the graphs at the end of the article show that the frozen sample lost about 10% of each aromatic, the nitrogen flushed one about 25%, and the normally sealed and punctured ones about 60%.

This article joins a dozen or so I've read that are looking to find measurements of the important coffee attributes like cherry quality, roast degree, and freshness, by measuring the ratio of two aromatic gasses. The papers use lab GC/MS gear, but a ratio of two gasses can be done cheaply in factories and storage facilities using a pair of specifically designed sensors. The procedure is to correlate ratios with sensory assessments. The 80% correlation coefficient for their freshness ratio translates to an electronic nose picking out the stale sample 8 to 9 times out of 10 from a pair of cups, which is getting into the usable range.

I have yet to hear about any of the proposed electronic noses being put into commercial operation; but the potential return must be good, since the labs keep trying to come up with them.

Nitrogen flushing is the SOP for all pods and capsules, by Starbucks in those big silver bags, and for the whole bean hopper replacement canisters used by Italians roasters for their bar deliveries. There are always several nitrogen flush packaging machines on display at the SCAA, so I'm guessing it's widely used beyond these obvious cases.

What is instructive is that freezing is simply dismissed as a commercial form of coffee storage despite everyone knowing it virtually eliminates staling. The business strategy of large coffee companies is to "add value." This means mechanically harvesting the coffee at source, and then doing everything in-house, from sorting to roasting to packaging, and to portioning and brewing if they can (the pods and capsules). Under this scenario, picking ripe coffee at origin, sorting it there, freezing to preserve it, grinding and brewing it fresh, etc, do not "add value," since they cannot be done in house.

It's a neat idea; but is it food safe? Don't recall seeing them in packaged foods.

There are practical problems too. A lot of this packaging tech is going into preground single serve items, like pods, capsules, and office coffee. This would have to make the oxygen scavengers insoluble when brewed -- it would exclude the classic preservatives -- tannins and other polyphenol anti-oxidants, because they are soluble. If the coffee is being done by a small roaster, the oxygen scavenger will be exposed to air when it is put in the coffee bag, and whenever the bag is opened by the buyer; it would need to handle that without losing all the reactants (for this, tannins might work).

Almost all coffee sitting on supermarket shelves has either been nitrogen flushed or vacuum packed for the last 30 years, when the cheap one way valves were first introduced. Packing machines that do this are not much more expensive than those which don't, so the marginal cost of doing it is virtually zero

The article was about a new method of measuring staleness chemically; not about preserving coffee. So it used well known fresh and stale coffee benchmarks to see if the measure correlated with industry standard tasting and packaging experience. It did.

Would supermarket coffees profit from extraordinary measures to keep them fresh?

In many cases, they use coffees that are so bad that they stale them prior to packing, since they taste worse fresh than stale. All in all, peak freshness is not an issue, since they are not selling to people who demand that it tastes great, only that it tastes inoffensive and expectedly coffee-like. I think supermarket coffee is fresh enough for what it is.

However, if you are willing to pay $100 per pound for an auction coffee that cups at 95 points, and just $20 a pound for coffee that cups at 90 points, then even the slightest degradation will ruin its value. In such cases, nothing but fresh roasted will do, and even freezing would be controversial, never mind any other sort of packaging. This is extreme; but it shows that the better the coffee, the more valuable freshness becomes.

Freezing coffee commercially, or other extraordinary measures would make sense if the supply of specialty coffee that needs to be fresh increased enough to make it a regular pantry item. Maybe if enough hedgefunds bought enough 3rd wave roasters, this too shall come to pass.