I am trying to reconcile different statements about when roasted coffee is best or at its peak. I've read many comments throughout the forum suggesting that coffees peak from 4 to 7 days after roasting, or 4 to 10 days, or up to 12 days. I found one thread where someone said coffee is best from 2 to 15 days after roasting, but generally the minimum time specified by most people is 4 days and anything over 10 days is usually considered stale.
While purchasing the four pound green bean espresso sampler from Sweet Marias, I found a statement that seems completely at odds with HB collective wisdom:
Coffee is best from 4 to 24 hours after roasting.
To the extent that any such declaration is at least partially a matter of taste, I doubt that SM is wrong. I also doubt that the pervasive HB collective wisdom is wrong. But no one really explains exactly what they mean when they make statements like these, so I'm left to wonder. Could these widely divergent statements be referring to different characteristics of the roasted coffee? Or is it that the preparation method, making a high pressure extraction (espresso) versus brewing coffee in other ways, accounts for the difference? Or is it just that opinion (individual taste) varies so much?
Our own local forum expert cupper, another_jim, says something interesting in What else is going on during coffee resting?
another_jim wrote:Straight out of the roaster, coffee has little aroma and tastes flat and unaromatic, even when cupped. The maximal variety in aroma (both good and bad) is between 8 and 24 hours. After that, the aromatics gradually decline. My guess is that the CO2, being a small molecule and having less mass than the aromatics, outgasses first. After eight hours, it is mostly gone, and the coffee starts losing its aromatics.
As to aging/staling and taste: Is it that coffee that is a day or two old is unpleasant, or just too "in your face." My feeling is that it's mostly the latter. If a coffee is all fruit and flowers, it'll taste good right off the bat; but if it has more aggressive aromatics, then it needs age for these to get into a good proportion.
But coffee chemistry is staggeringly complicated, so blanket statements like this probably have a huge number of exceptions.
Perhaps another_jim's comments hold the answer to my question, or what might be my question if I understood more about coffee than I do. Aroma is only one aspect of coffee. There is also flavor, body, mouthfeel, and acidity, at least. Perhaps different characteristics age or stale at different rates, and the complexity of coffee chemistry is just too great to reduce so simply in any case.
But still I hope to learn why it is for espresso that coffee must age to a point that some would consider it stale before it is regarded as having reached its peak?