Today I’m continuing the post series on off flavors. Sometimes when a beer is brewed, stored, or just handled incorrectly it can gain off flavors that make the beer unpleasant to drink. While nothing harmful can live in beer, there are a variety of off flavors that can make beer just not fun to drink. In this post we’re looking as the astringent off flavor in beer.
What Is It?
Astringency in beer is a flavor and aroma that comes from a few sources. The most common source of the astringent off flavor is from over-milled grain. If too many husks from the grain are in your mash due to over-milling, polyphenols or tannins can escape, giving an unpleasant tart, vinegar-like taste.
The astringent off flavor is characterized mostly by a vinegar-like, puckering taste with a dry sensation. While this can be a good sensation in a purposefully sour beer, astringency in a beer is never good. A dry taste similar to a high-tannin wine can be present, as well as a powdery or metallic taste. Think the drying sensation you get from sucking on a tea bag.
How To Avoid It
The biggest way to avoid astringency is by not over-milling your grain. When milling, grains are supposed to be cracked, not fully milled. You can also make sure to sparge with the correct amount of water and at the proper temperature.
Make sure your mash pH doesn’t exceed 5.2-5.6, as well as not over-hopping during the boil. Both can lead to the astringent off flavor. Lastly, if adding fruit to your beer, never add them in the boil, but instead add them in the fermenter or to the wort after boil is complete for at least 30 minutes.
Just like acetaldehyde, astringency doesn’t generally come from contamination or poor sanitation when brewing, but instead from the ingredients themselves.
Sour beers are amazing, complex beers that give a sour, pucker feel and taste when drinking, but they steer clear of astringency. That is the sign of a good sour beer, when it has the sour properties without making the leap to astringent.
Make sure to check out the other posts in my off-flavors series. These can really help you make the best beer possible when home brewing, and can help you understand why some commercial beers can taste off, too.
Thanks for reading,