Find out the common techniques and processes brewers use to produce a beer under 0.5% ABV.
You don’t need me to tell you the demand for non-alcoholic beer has exploded in recent years.
One reason why is we’re drinking less alcohol. Many of us have taken a conscious decision to drink moderately and more people than ever don’t drink at all.
But it’s not only a change in our drinking habits that has increased demand for low and no beers. The quality and choice of non-alcoholic beer has also improved dramatically, thanks to innovations in the way it’s produced.
This article looks at the common techniques and processes brewers use to produce a beer that meets the widely accepted definition of “alcohol free” or “non alcoholic” – under 0.5% ABV (alcohol by volume).
How is non-alcoholic beer made?
Beer is made by “mashing” malted barley (sometimes with other grains) with hot water to extract the sugars and create a wort.
The wort is then boiled with hops and fermented, where yeast eats the sugars in the wort and turns them into alcohol and other by-products such as carbon dioxide and compounds that add flavour.
Almost all non-alcoholic beers start life in the same way, but there are a few differences, usually in the latter stages of the brewing process.
So what are the different ways non-alcoholic beer is made?
In a paper titled “Alcohol-Free Beer: Methods of Production Sensorial Defects and Healthful Effects“, researchers from the University of Tehran and Shahid Beheshti University highlighted four common methods for producing non-alcoholic beer.
They are:
- Dealcoholisation
- Limited fermentation
- Dilution
- Fermentation free
Some brewers use a mix of these methods for the same beer. Let’s look at each method in more detail.
1. Dealcoholisation
With dealcoholisation, an alcoholic beer is brewed in the traditional way.
The alcohol is then removed using a method such as steam distillation, water vapour or gas stripping, or reverse osmosis.
Steam distillation
The boiling point of alcohol is lower than water. This means it’s possible to remove alcohol from beer by heating it.
An issue with this is that many of the flavours are removed along with the alcohol. Heating beer can also “cook” it, affecting the flavours that are left behind.
Producers can reduce this effect on flavour by using equipment that heats the beer under low pressure, which makes alcohol and water evaporate at a lower temperature. This is often known as vacuum distillation.
Producers can also use hi-tech equipment such as a spinning cone column system to separate the flavour compounds from the distilled alcohol, then add them back into the dealcoholised beer.
Water vapour and gas stripping
This technique for dealcoholising beer involves using hi-tech equipment to gently heat the beer under vacuum, then pass water vapour or a gas such as nitrogen through it.
The conditions are set so the water vapour or gas carries the alcohol away from the beer.
As with steam distillation, some flavours are removed along with the alcohol. Producers may separate these from the alcohol then add them back into the dealcoholised beer.
Reverse osmosis
Reverse osmosis involves more hi-tech equipment, this time using high pressure to force the beer through a membrane.
The membrane captures larger molecules – including those that contain the beer’s flavour – but allows smaller molecules including water and alcohol to pass through. This leaves a concentrated version of the beer.
The water and alcohol are then separated, for example by steam distillation, with the removed water added back to the concentrated beer.
2. Limited fermentation
The alcohol in beer is produced during fermentation, when yeast breaks down the sugar in the wort.
If you limit the amount of alcohol produced during fermentation to under 0.5% ABV, you’ll have a low-alcohol “non-alcoholic” beer.
There are three common ways to limit fermentation and brewers can use a mixture of these methods to achieve a beer with less than 0.5% alcohol content.
With each of these methods, the beer is made in the traditional way.
Limiting fermentable sugars
One way to create an ultra-low-alcohol beer from the off is to reduce the amount of fermentable sugar in the wort. The less sugar the yeast can ferment, the less alcohol is produced.
Brewers can do this by using grains that produce less fermentable sugars (such as rice or maize) or by using techniques that extract less fermentable sugars out of the grains at the mashing stage of the brewing process.
Using special yeast strains
Another way to limit fermentation is to use special yeast strains. For example, a strain that can only produce alcohol in low amounts or a yeast strain that can’t ferment maltose (one of the main sugars produced by malted grains).
A downside to this is that more sugars survive fermentation, leading to a sweet beer if lots of sugar is still present.
Some of these yeast strains also produce a high amount of lactic acid, which gives the beer a sour flavour. This works well in some style of beer but can be an undesirable flavour in some styles.
Interrupting fermentation
Fermentation only occurs when the conditions such as temperature are right. Therefore, brewers can slow or stop fermentation by tweaking the environment the yeast is working in.
For instance, heating or cooling the fermenting wort can slow fermentation or stop it completely.
Fermentation in a pressurised environment and adjusting the acidity of the wort can also restrict or halt fermentation.
Non-alcoholic beer produced with limited fermentation can result in a sweet beer, depending on the ingredients used. It may also taste “worty” or unfinished.
3. Dilution
Using this method to make alcohol-free beer, brewers produce a concentrated beer in the traditional way using a significant amount of hops and grains to create a concentrated beer high in flavour and body.
After fermentation, they dilute the concentrated beer with water until the alcohol level is under 0.5% ABV, and then re-carbonate it.
4. Fermentation free
Fermentation doesn’t just give beer alcohol and fizz. It also contributes to its flavours and aroma. Ultimately, it’s what makes a beer a beer – without fermentation it’s just sweet wort.
That doesn’t mean that every non-alcoholic “beer” on the market has been fermented. Some producers avoid fermentation altogether, making other tweaks to the production process and recipe to create a drink that looks and tastes like beer.
