I've been using ALDC for about a year or more on nearly every beer (mostly lagers) and it works pretty well. It has a shelf life and as it ages the potency is reduced, so be aware of that. I had a beer where I couldn't detect diacetyl, but my wife could. I dosed it with some fresh ALDC and the next day it was gone, so it works post fermentation. I believe it starts to denature @ 4.3pH. No butter in dry hopped beers when I add it with the dry hops.