I found a recipe elsewhere that incorperated lactic acid to give the sour character to their beer. It said to add the acid to the finished beer. I tried adding some 88% lactic acid (about 300uL) to 12 oz of our Irish Stout. It had the desired effect. The question is: Can you acidify the beer before bottling or would the drop in pH inhibit the yeast from converting the priming sugar?