Alcohol Chemistry

How is alcohol-free beer made?

Infographic on how alcohol-free beer is made. Definitions of alcohol-free beer vary in different countries, with some allowing small amounts of alcohol. Alcohol-free beers can be produced by avoiding fermentation entirely, but this can impact flavour. More common methods include dilution (where a concentrated beer is produced then diluted), dealcoholisation (where alcohol is removed via distillation or membrane filtration) or limiting the production of alcohol (by using specialised yeast or low fermenting temperatures).
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Alcohol-free beer is increasingly popular and sought-after as people become warier of their alcohol intake. A few decades ago alcohol-free beer was a poor imitation, but these days it’s steadily improving and some examples can hold their own compared to the real thing. This graphic takes a look at how alcohol-free beer is defined, the range of ways in which it can be made, and how these methods work.

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Port wine chemistry: Types, colours, ageing and flavours

Infographic on the chemistry of port. There are several different types of port: ruby port is aged for a short time in oak vats; tawny port is aged in oak barrels for longer periods; rosé port is a newer style of port made with minimal contact with grape skins; and white port is made from white grapes. The colour of port is caused by anthocyanins found in grape skins. As ports age, anthocyanins form pyranoanthocyanins and polymeric pigments, leading to a change towards an orange hue. Sotolon is a key odour molecule in aged port, and its concentration correlates with the length of aging. Barrel-aged ports gain some compounds from barrel wood which also contribute to favour and aroma.
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Port’s often relegated to the festive period, and forgotten about for the rest of the year (at least, in the UK). This is a shame as if you look beyond the standard ruby port, there are several other delicious types, particularly the varieties that are aged for longer periods of time. There’s also some interesting chemistry behind these varieties and how they transform during ageing.

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