I have an oatmeal stout bottled.. I was asked to bring soem hom brew to a party last night and took a couple of each kind I have bottled. Anyway they went nuts over the oatmeal stout which I hadn't tried yet.. I got home and opened one and it was AWFUL... I don't know the proper description but astringent sounds right..plus a huge foamy ( pop like) head............. This is the third time I have opened individual bottles that were "off" and the rest of the batch be fine.....my sanitation process seems fine and this was a new bottle that was cleaned and sanitized.