When Does Coffee Go Stale?

I love watching crema levels. A day after roasting, our espresso blend is so crem-tastic as to include little actual coffee. Three weeks after, the ratios have reversed. About 4-7 days into a batch, I think that the crema sweet spot has been reached. Taste-wise also. Knowing this allows me to alter how I make a shot and also when to order (we only like keeping around coffee for about a week).

With all the espresso evaluation stuff that has been going on, some defining is being refined, especially at Coffeed.com (I post here because no new members are allowed there). What I still haven't seen, though, is what exactly "stale" means. How do we know when a coffee has gone stale? How does roast level affect this? Transportation methods? Green quality? What about rates of staling whole versus ground? (I've heard that ground coffee goes stale in 30 seconds, but have yet to see anyone reference any scientific data).

That, I think, is the crux of the issue: science. Most barista/shop owners don't have the fancy-schmancy equipment needed to get past the anecdotal level. Do I think our espresso goes stale after two weeks? Actually, no. But that is my opinion from working with/tasting it. I'm sure others would disagree, both other professionals and customers. The only people who do seem to have the equipment live in Italy at Illy Cafe, but their research skews towards pod brewing--conveniently considering they produce a lot of pods. There is no independent, third-party scientific research going on that I know of. It is frustrating, especially since espresso preparation requires so many steps to achieve a decent, not to mention a superb, shot. Like I said in the last post, where's the beef with polishing? I've been dabbling this week and haven't noticed a huge difference: the bottom of my tamper is scuffed up anyways because I'm a complete newb (Chris Deferio pointed that out to me, analogizing the tamper with the pupil of the eye), so what sort of "polishing" is going on anyway? Add to this my lack of current financial means to afford a Scace device (have you seen the price of the Scace2? Wowsa.) and no PID control on our machine. But we still pull lots of good shots.

I do have hope, though. One of my professorial friends, a Chemistry teacher at Geneva College here in Beaver Falls, is interested in coffee science. Maybe some day I'll have access to fancy-schmancy equipment, or, better yet, a chemistry intern to do some research for me. In the meantime, I'll keep plugging away trying to bring you the best tasting espresso we can. Bottoms up.

PS--When someone asks what drip brewed coffees you have available that day, is it bad form to say "On tap today we have House Blend and Sumatra..." I said that today, even though I do not recall actually tapping a keg/airpot. I stopped midsentence (the ellipsis in the quote above) and stared dumbfounded at the customer until he assured me that he understood, despite my (apparent) best efforts to confuse myself.