Vinegar is a great quick fix for lowering your pH. But for long term use it is not. It has no buffers in it to keep pH down. You need to find a better pH lowering chem.
And I don't think it will impart a flavor to the final product.
Pick up some General Hydroponics PH UP! Works great and doesn't cost too much, especially if you buy the dry powder and mix your own liquid! That's what I do!
You can get 1.5 pounds of both the UP and DOWN powder for about $25.00 online.