I feel like Ive had some astringency issues on my last few batches. Not bad, but enough to make me want to hunt down the cause(s). Recently, SWMBO presented me with a copy of Brew Chem 101 by L. Janson, PhD. I cant quote him exactly because, well, Im supposed to be working and hes at home, but he says that one cause is the re-absorption of the kraeusen by the beer. He says that you should always use a blowoff tube so as to get as much of the kraeusen out of the carboy as possible, thus avoiding astringency.
Well Im sorry, L. Janson PhD, but this set my BS detector off. If that were really true, I figured, then our discussions about kraeusen, blowoffs, yeast, and headspace would be much different. There would be enterprising souls marketing Kraeusen Skimmers and Tubulators (patent pending) to eager homebrewers. Is there any truth to what he is saying?
On a related note, Papazian offers the advice do not oversparge. Can someone explain this to me? How do you know when enough becomes too much?