I need to get a better handle on this as it's so often asked. What is happening to the beans and how the taste changes. From the bits and pieces I've gathered, at the start co2 is being strongly released and the rate of it rapidly decreases after a couple days(varies). Oxygen replaces the co2. The oxygen starts a process of staling. H2O retained in the bean starts to affect the bean in negative ways. The oils migrate towards the surface(varies) and will become rancid. The flavor gets better after some time(varies) and then gets worse.
The only reason I've heard of why the roast doesn't taste best right out of the roaster is the excess of co2 which I assume when mixed with water and saliva create carbonic acid(?) that adds a bitter/sour(?) taste. So does this just temporally masked the desired flavors? Do flavors really develop (term often used)? If so, how?
Ed

Jim
Yes tannins make sense and are interestingly in many of the descriptors we use, grapes/wine, nuts, tea, citrus/fruit peels/skins(?), chocolate, blueberries, etc

A tannin content in coffee green and roasted reference, "The green beans contained 6.6 ± 0.6 mg g-1 weight tannic acid equivalents as found by protein precipitation (n = 5, ± SD) or 6.8 ± 2.3 mg g-1 by spectrophotometry. The same figures for roasted beans were 18 ± 1.7 and 17 ± 2.7 mg g-1, respectively."
tannin content
ps noah, it's my grinder hopper and gauge modification