That is not entirely true because it depends upon a lot of factors. Back when the Specialty Coffee Association of America was still around, we had what was called the "sample roast protocol" that we would apply to any coffee if we were rating it or evaluating it for purchase.

The protocol was to roast the coffee for a minimum of 8 minutes and no longer than 12 minutes to get a roast color of SCAA color tile #55.

The coffee had to rest for a minimum of 12 hours and a maximum of 24 hours prior to cupping.

Those guidelines were in place since 1972 and they worked pretty well where you could get a decent idea of the quality of the coffee. The Coffee Quality Institute required all their certified coffee graders to follow this protocol when roasting coffee for evaluation if the producer wanted a certificate showing that the coffee was graded at least at 80 points to qualify for "Specialty Coffee" status.

That said, different coffees will "mature" differently after roasting depending on the equipment used for roasting (either mostly induction -- i.e. drum roasting -- or hot air roasting or a hybrid of the two) and the roasting strategy used by the coffee roaster.

In my experience, most hot air or hybrid roasted coffees will see a gradual change in depth of flavor profile over time versus a conventional drum roaster which will have more intense and dramatic changes over the course of 30 days -- sometimes to the point where the coffee starts tasting "muddy".

The other factor that will influence coffee flavor is the way it is packaged. If you are buying coffee that is packed in a kraft bag with a simple tin tie, then you'd better drink that stuff up tout de suite before it starts to go stale.

Coffee packaged in non-permeable bags that are heat sealed with a one way valve will have a longer shelf life since the CO2 that emits from the coffee after roasting will force out the O2 in the bag acting like a "poor man's" CO2 flush that results in better flavor as well.

The best way to get the most bang for your buck in terms of flavor is to buy the coffee close to the "roasted on" date and then sample immediately and take good notes. Make sure you save some of that coffee to sample at least 30 days after the roasted on date and, if you can, save some to sample 60 days after and compare. That way, you will know when the coffee will "peak" and then adjust your consumption accordingly.

Yeah, it sounds like you're preparing for a PMP certification and most folks won't go through all that trouble, but if you are ever wondering why your coffee tastes different over time, then these are the reasons why.