I brewed an APA/IPA (it's debatable) on 10/25 - bottled 11/07 - that has a slight astringency to it. It's not unbearable, just enough to give the beer a roughness after the swallow, leaving me apathetic about taking another swig. I do not think that the astringency came from the grain, however, because I've never had any trouble before. This time I also used some distilled water to cut the well water, which should lower the pH of the mash and lessen the risk of astringency. I also do a single batch sparge.
I read in Palmer's How to Brew that astringent flavors can also come from overuse of hops. I used a total of 8 oz of pellets in this beer. This level of hopping is common in high-gravity IPAs. My theory is that the relatively small grain bill of this beer provided few proteins to bind to hop polyphenols (tannins) from the hops, resulting in astringency in the finished beer.
Is this a reasonable theory? Has anyone else noticed astringency from hops?
CO2: 2.7 vol.
7.5 lbs Weyerman Pils
2.5 lbs Marris Otter Pale Malt
0.5 lbs Caramunich (60L)
0.25 lbs Crystal (120L)
0.25 lbs sucrose boiled 90 min
10 min - 1.0 oz Cascade (5.4% AA); 1 oz Columbus (14% AA)
5 min - 2 oz Cascade; 1 oz Columbus
0 min - 1 oz Cascade; 2 oz Columbus