Taste, carbonation, and mouthfeel in beer

Which tastes do you taste in beer?

The tongue detects sweetness, sourness, bitterness, salt, and umami, the savory taste of broth. In beer, the first three matter most. Sweetness comes from the malt sugar that the yeast hasn't fermented. Acidity is subtle in most beers, but it's the whole point in Berliner Weisse, Gose, or Lambic.

Bitterness comes from the hops. During the wort boil, their alpha acids transform into soluble bittering compounds. This is measured in IBU, International Bitterness Units. A weissbier sits at 8 to 15 IBU according to the BJCP, a German Pils at 22 to 40, and an American IPA at 40 to 70.

The number alone can be misleading, though. Plenty of malt sweetness masks bitterness, while a very dry beer lets it stand out more. A Doppelbock at 16 to 26 IBU can therefore seem milder than a Pils with a similar value. Tasters speak of the balance between malt and hops.

What does carbonation mean in beer?

Carbonation refers to the fresh, prickling sensation that dissolved carbon dioxide creates on the tongue. A beer with good carbonation feels lively and refreshing. Without it, a beer tastes flat and tired, even if everything else is right.

How much carbonation is appropriate depends on the style. Weissbier and Belgian bottle-conditioned beers are strongly carbonated, meaning packaged with plenty of CO2, and sparkle almost like sparkling wine. An English cask ale, by contrast, is only gently prickly. An Irish Stout from the tap is often poured using a gas mixture with nitrogen; the tiny bubbles make it velvety and creamy.

Full-bodied or lean: body, warmth, and astringency

A beer's body describes how heavy it feels in the mouth. It depends on the portion of the malt that the yeast can't ferment, mainly long-chain sugars. A highly fermented Kölsch or Pils feels lean. A Doppelbock or a Dubbel feels full-bodied, almost syrupy. Oats and wheat make a beer even softer.

With strong beers, alcohol warmth comes into play too. A Tripel at 7.5 to 9.5 percent should warm the throat without burning. A sharp, solvent-like impression points to fermentation that ran too warm. Astringency is a dry, puckering sensation like strong black tea. It usually comes from tannins in husks or hops and is unwelcome in almost every style.

Finish and overall impression: what lingers after the sip?

After swallowing comes the finish. Some beers end short and dry, inviting the next sip. Others linger long, with bitterness, roasted notes, or residual sweetness. A good Pils leaves a fine, clean bitterness that fades quickly. If it clings to the tongue, long and harsh, tasters speak of a lingering bitterness.

At the end comes the overall impression. Do aroma, taste, and mouthfeel match each other and the style? An Altbier should be malty and robustly bitter at the same time. If it comes across as only sweet or only bitter, the balance is off. Anyone who answers this question for every beer has completed the tasting.

A good comparison here is Kölsch and Alt, neighbors from the Rhine. Both are top-fermented, both are cold-conditioned, and both taste cleaner as a result than many other ales. Kölsch is pale, slender, and delicately bitter, with a short finish. Altbier is copper-brown, more robust in malt, and often distinctly more bitter, with a longer, drier finish. Tasting both side by side reveals just how much malt color and hop dosage alone can change on the palate.