A critcially important question as it relates to “peak flavor”.
To answer it accurately, we need to define “opiminally fresh”. That of course varies from person to person, from bean to bean, from roast depth (and recipe) to roast depth.
Throw in another important and related question which is “optimally fresh - for what?” e.g. dark roast for espresso versus light roast for brew, and it can get complicated.
FWIW my records indicate that for my definition of peak flavor, the following guidelines apply::
Dark roast peak between 10 and 17 days post roast
Full City (medium/dark) peak between 14 and 24 days
Medium roast seem to be the same as FC although I’m still testing to confirm this
City (medium/light) and Light: I haven’t tested yet.
Of course some will love beans three days post roast and others say they have their best experience three months later. Go figure.
The above may seem like a diversion but it’s necessary to define “optimally fresh” for you, because if you are more of the “3 months post roast” opinion, then the answer probably doesn’t matter much.
But to answer your questions more directly (finally) a standard bean bag with a one way valve will do the job as well as a canister of any description, assuming you are going to consume the beans within the guidelines above.
Vacuum sealing beans will shorten the life span of your beans. I’ve tested it and there are lots of theories as to why but I’m not sure anyone knows for sure. Suffice it to say that vacuum sealed beans deteriorate faster than those kept in a standard one way valve bag. I thought for sure it would be the opposite, which is why I bought a rather pricey German vacuum sealer which now collects dust. Vacuum sealing with a less powerful machine or stopping the sealing prior to the bag feeling as tight as a brick, is better according to @DavecUK because you are not sucking out aromatics which are important to flavor.
What seems to be the indsputably best way of storing beans to maintin Peak Flavor is nitrogen (or similar) flushed canisters. But as mentioned, provided you are starting of with a bag of beans that are going to be consumed within 7 - 10 days, it’s not worth th fuss - gas cylinders that will need refilling, canisters for the beans, tubes in between. Just buy/roast smaller qualntities, keep them in the one way valve bag and consume before they begin to deterioriate.
The easiest way to tell if a bean is past its peak is to pay attention to viscosity and flavor and pour time. Beans that have fallen off the peak ledge, will almost overnight (OK, lets say 48 hours) begin to pour thinner, taste flatter and you end up with more weight in the cup for the same grind size, pressure profile and pour time. It is possible to simply load a couple more grams of beans into your grinder so that the basket is packed with more grinds and yes, that will slow the pour down a little so your “in cup” weight is the same, but the espresso will still be post optimal.
And you need to use the same bean daily because “thinner” and “flatter” are relative terms. Relative to what? Relative to the previous pour, and if that was 30 days later, the comparison becomes more difficult.