I brew 5 gallon batches, full boil, in an 8-gallon BK. I like IPA's and typically have a small boil over no matter how hard I try not to. Also, the last two batches I did a 75 minute and a 90 minute boil and boiled off a ton of wort. When that happens, I usually top off before I pitch my yeast with filtered water. However, I had someone notice a sour taste in my most recent IPA (I didn't taste it due to the hops, but he claimed he did). So I'm wondering if it may have been from the filtered water. I have it in a Brita pitcher, so the pitcher and the water haven't been sanitized. I'm wondering if it got an infection from this. I noticed some people add water to the boil if too much is lost, which makes since unless you're worried about hop utilization. I'm not really worried about that at this point. I've only brewed 7 batches. Any ideas?