I've been doing the Get Shredded diet for a few weeks now, and the diet calls for 40 grams of BCAAs a day. If you've ever actually had BCAA powder, you would know that this is like a death sentence. The powder isn't water soluble, and it tastes like battery acid mixed with burnt cat hair.
I was just mixing up my third dose of the day, and I found a way to forcibly dissolve the powder. If this is common information, then feel free to flame, but I've got to say that I searched for hours on the best way to take BCAA powder without any results.
1) Put liquid in a big glass. The more liquid the better. Don't try to concentrate it to minimize the volume, or you may end up throwing it up, which will make the rest of the dose especially gross. Instead, try to dilute the powder. 15 bearable sips is better than 10 seconds of hell.
2) Artificial sweetener is a life saver. I've found that Propel Zero, Sprite Zero, and especially Minute Maid Lite Lemonade are all useful solutes for the powder. In fact, the Lemonade is so strong that I couldn't even taste the BCAAs.
3) And this is the important part. You have two viable options in getting the solution down pain free. The first is to stir with a fork in circles to get the powder kind of wet, even though it won't dissolve. Keep stirring as you start to drink, and the liquid will more or less flush down the powder painlessly.
What I discovered, however, is that although you cannot dissolve the powder, you can mix it. Submerging the powder was always a difficulty for me, but, if instead of circularly, you just slide the fork back and forth, you create a vacuum for the solids and they start to sink.
Best of luck.