Low-alcohol beer has been around in one form or another for centuries, and especially in Medieval Europe was imbibed by a large proportion of the population. Because of the boiling involved in brewing, the beverage (usually known as small beer) was considerably safer to drink than water, which tended to be contaminated due to poor hygiene standards at the time. However, it was not until 1919 that the first non-alcoholic beer as we know it was produced.
The Volstead Act was passed by the US Congress in January 1919, establishing prohibition and thus limiting the alcohol content of beverages in the United States to a maximum of 0.5% ABV. In order not to go out of business, breweries across the country raced to produce a product that was in line with these new laws. The simplest way to achieve this was to add one additional step to their brewing process – evaporation. By either boiling or raising the temperature of their beer above the boiling point of alcohol (around 79°C), the breweries could remove enough alcohol to satisfy the National Prohibition Act, and have a product they could sell to their usual customers.
And so this continued until March 1933 when prohibition laws were repealed, and brewers in the United States could once again produce their product with the alcohol intact. However, over the preceding 19 years many people had become used to the simpler blander flavour that non alcoholic beers were providing, and so began the light beer movement.
Growing health consciousness in recent times, especially amongst people in the younger age brackets, has helped to spur on a resurgence of non-alcoholic beer production. But nowadays people are used to a better flavour from their beer, especially with the craft beer movement having taken hold of the market. This has lead to more involved and technical processes being used in the production of non-alcoholic beer.
The most basic method of removing alcohol from beer is to heat it until the alcohol evaporates. This is efficient, but as you’re essentially cooking the beer again, many flavour compounds are simply destroyed in the process, leaving a bland substance that has more in common with a tea than with a typical beer. For example, the hop essential oil myrcene, important for flavour in so many brews, will start to boil off at about 64°C versus alcohol boiling off at about 79°C.
In an attempt to stop this happening, many non-alcoholic beer brewers will employ a technique known as vacuum distillation. This involves creating a vacuum in the brewery’s distilling equipment, which in turn will lower the boiling point of alcohol, meaning that the beer does not have to be heated as vigorously as before. Heineken states that their Heineken 0.0 utilizes vacuum distillation in it’s production [https://www.heineken.com/us/heineken00/faq].
An alternative to distillation in removing alcohol is reverse osmosis – a type of filtration. A strong semi-permeable membrane is used as a filter, and the beer is pushed at high pressure through this using industrial machinery. Depending on the quality of the membrane, the only substances that should pass through it will be the water and alcohol, and probably some volatile acids from the malt and hops. This also leaves a syrup of sugars and flavour compounds on the other side of the filter.
Standard distillation is then performed on the mixture of water, alcohol and flavourings, and when the alcohol has been removed the remaining liquid is then added back to the syrup. Because the main flavouring ingredients of the brew are not subjected to heat, the beer retains much of it’s original flavour. However the process does have a negative effect on the beer’s foaming properties and body.
Whatever method of removing alcohol the brewery chooses to use, the result is still flat. For most standard beers, carbonation is achieved after they’re bottled, with the remaining fermentation process going on inside the bottle. Because this fermentation produces some alcohol, it won’t be a viable method for finishing non-alcoholic beers. Most breweries will simply inject some carbon dioxide into the beer during bottling. This unfortunately also adds carbolic acid into the mix, which can give a somewhat metallic taste.
There are a number of modern techniques used by brewers wishing to create a good non-alcoholic beer, though each adds extra hurdles for them to overcome if they want to produce a great tasting brew. Thankfully many brewers are surmounting these obstacles and filling the market with flavoursome non-alcoholic beers for all to enjoy. Cheers!