Something that some people don’t give much importance is the head on the beer. By law in the UK all beers have to be served with a 5% of head (I mean, 95% of the glass is beer, and the 5% foam). And even so it’s by law, some bright minds ask for a top up…like if these 20 ml extra of beer were going to make them more pissed. When I was in Czech Republic a couple of months ago, after asking for a pint of beer I was given something like this:
and…well, there has to be a limit, because half a pint of foam is ridiculous. I’d say that 5% is perfect. And foam has an important role in your beer. Soda and champagne both dance with carbonation, but only beer manages to sustain a head.
Those tiny bubbles add a bit of acidity to the beer that, when combined with the prickling sensation on the tongue, give it more of a crisp snap at the finish. That’s why highly carbonated, light-bodied beer are satisfying on a hot day. In contrast, beers that are lower in carbonation (like cask ales or stouts) seem to have a heaviness on the tongue and are more popular during winter times. Carbonation affects as well to the aroma and taste as well. As CO2 rises off the glass, it lifts volatile aromas up and out of the glass, too. It’s the opposite with flavour, carbonation scrubs both malt and hop flavours but especially bitterness.
Some glassware is designed to keep and help create the CO2 to generate bubbles. In the picture below I show you in the end of the glass, the area called “nucleation site”.
To end the article, and going back to the head in the beer, foam is a more ornamental function of carbonation. The head can add creaminess to beer’s texture., though -especially in stouts like Guinness, which served with a mix of nitrogen and CO2. A good beer not will only retain its head, but leave a lattice of residue in the inside of the glass
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