What is astringency in beer?

In general, we identify astringency as that sensation that suddenly dries out your mouth. Can’t picture it? Try leaving a tea bag in hot water for too long and then sucking on the bag, or savor a piece of wood. That feeling that makes your tongue pucker—that’s astringency. It is not necessarily related to bitterness, which is a flavor that stimulates the taste buds. Astringency is also perceived on the roof of the mouth and even in the gums, and is considered a flaw that can ruin a beer. It is not a flavor.

The cause behind astringency is usually found in tannins. This substance is present in plant fibers. We find it, for example, in wood, leaves, and seed husks. It also becomes more noticeable when the grain is roasted. Even hops are a natural source of tannins (polyphenols). That’s why some heavily hopped beers give us that “rough” sensation in the mouth. It’s a flaw that can appear in some IPAs with multiple dry-hopping additions if they’re not executed properly.

Other factors that can lead to astringency are highly alkaline water with elevated pH, or the presence of grain sediment (solid residues) in the finished beer. Even in beers that contain spices or citrus peel, we can also find it in these additions if we don’t calibrate their use. As we can see, there is no single cause that explains astringency.

Any tips to keep the beer we’re brewing from turning out astringent? Of course, take note!

• During mashing, the pH should range between 5 and 5.5.
• Do not extend the maceration time longer than necessary.
• Avoid adding more hops than your recipe calls for.
• The proportion of dark malts should not exceed 10%.
• Control the water temperature, as tannins become more soluble above 76°C.

Even if you find astringency in styles where it is to be expected, such as APA, IPA or beers with dark malts, you should not mistake it for a defining feature. A well-brewed beer, regardless of style, should never be unpleasant. It is a flaw, and it should be perceived as such both by the end consumer and by judges in competitions. Don’t let anyone talk (or drink) you into believing otherwise: it is neither desirable nor acceptable once it ruins the sensory experience.