I just had a quick question for everyone out there in beer land. I have been reading a lot about brewing and have finished palmer's book and also yeast by White and Zainasheff.. I feel really good the more and more I brew, but the only thing I still strive to understand all are the different off flavors: (tannins, esters, diacetyl, astringent, phenolic etc etc). I have read and read about them and have an idea of how they taste but not really. I was curious if anyone out there has examples of ways to actually taste these flavors separately (I read somewhere about artifical butter and put it some light beer for diacetyl taste). Someone had said to me at one point that you can buy vials that contain all these off flavors so you know how to describe what your tasting when drinking it. Has anyone heard of this or has ideas to get a better understanding on how to sample all these so you know what its like in a beer. Or even mixing stuff in beers that would yield these flavors? Thanks!!!!!!!!!!!!!!!!!