There has been alot of talk over the years in the whiskey community about the differences between small barrels vs large barrels. I have a few good links below for you to read through from well respected experts, so you can get more in depth information if you wish.
Long story short, smaller barrels produce inferior whiskey. The main reason is that they have an un-ideal ratio of wood surface area to liquid volume. The smaller the barrel is, the more charred wood surface area there is in contact with any given volume of liquid inside of the barrel. The ratio that exists in a 53 gallon has been shown to produce the best results, and this is why Beyond Barrel Bottle Aging Staves create this very ratio when placed into a standard bottle of liquor (750 ml).
Aging isn't just about adding flavors to a liquid as if you were pouring flavoring into your bourbon. There are hundreds if not thousands of different biological and chemical aging reactions that take place. The best analogy I have heard to explain why 53 gallon barrels produce the best results is that aging is similar to cooking. You can't stick a turkey into an 800 degree oven for a shorter amount of time and expect the same results you get if you cook a turkey at the correct temperature for a longer period of time. In this analogy the ratio of wood surface area the volume of liquid is exposed to is equivalent to oven temperature. Having the right ratio gives you the best "cook".
Try aging or finishing your favorite spirits or cocktails with the correct ratio using Beyond Barrels Bottle Aging Staves!