How to Brew Low Alcohol Beer

If you go on Untappd and look at the top rated beers, you’ll see a trend: they all seem to be high ABV. In fact – as of writing – I had to scroll to the 18th position to find a beer below 10%! And still, it was 8.4% which is on the stronger side. Despite this, low alcohol beers have come on leaps and bounds the past few years and good examples can even be found on supermarket shelves.

Sometimes it’s nice to have a few beers and not get drunk or feel hungover the next day. As delicious as beer is, it’s sensible to moderate alcohol intake, and as homebrewers with access to a lot of beer, we can moderate easier if our beer is low in alcohol.

The UK government’s definition of low alcohol beer is no more than 1.2% ABV, with alcohol free beer being 0.05% ABV or less. There is another type of beer called a “small” beer which is a stylistic description (as opposed to a legal one) and sits between around 1.2%-2.8%. Colloquially, a low alcohol beer can be anything sub 4%.

How does a brewer go about making beers with less alcohol? The main issue is to keep the mouthfeel from being too watery and for the beer to have as much a flavour punch as a regular strength (4-5% ABV) beer. Here are some ways to achieve that.

Brew Styles Which Already Have Low ABV%

Take a look at the BJCP style guidelines and you will find dozens and dozens of different beer styles with a vast range of flavours and alcoholic strengths. You might even be pleasantly surprised to see the number of beers which can be brewed with low alcohol. Some of my favourites are:

• Ordinary bitter: a well wounded beer which exhibits yeast esters, maltiness and a hoppy bitterness. ABV range starts at 3.2%
• Gose: a tart wheat beer brewed with coriander and salt water. Often made into a sour beer and/or flavoured with adjuncts. Whilst guidelines suggest 4.2% it works really well as a low 3% beer
• Berlinner weiss: a very sour beer brewed with wheat and usually sub 4%
• Table beer: not exactly a style, but a low ABV version of literally any beer. The term was originally used by Europeans in the middle ages to describe a generic beer drunk with meals on an average day. These days, it can be a low ABV pale ale, lager, stout, whatever you’d like!
• Kvass: Not exactly a beer, but a fermented beverage made from toasted black bread, raisins and other fruits. Usually about 1-2% ABV.

Utilising Hops

There is a reason so many craft and smaller breweries will make IPAs as their core beer. Hops carry so much flavour and to an extent can mask off flavours or “lack of” flavour. Hopping a low ABV beer can give the drink more character. There are a couple of caveats to a high hop rate, like hop burn and losing volume, but read our article on how to use hops and you should be ok.

Something to note is that a low ABV beer tends to require less hops as there isn’t the malt profile to balance it out. This is usually one of those times when IBUs don’t give the full picture, but focusing on the BU:GU ratio will help. This is a ratio most recipe builders include and gives a better idea of balance between malt and hops.

Adding more hops can bring out their characteristics more and can be a really good way to experiment with different varieties whilst keeping the beer easy to drink.

Utilising Malts

As you probably know, yeast eats sugars which creates alcohol and carbon dioxide. So to reduce the amount of alcohol there needs to be less sugar. To reduce the sugar, there needs to be less malt which is where the sugars come from. This is often done and the lower the beer’s ABV the less malt is used, but malt contributes so much more than just sugar. It imparts body, flavour and colour and reducing the malt can impact these qualities of the beer.

This can be mitigated by using more adjunct malts in place of base malt. Adjunct malts provide body and colour and tend to have less fermentable sugars. Using grains like wheat, carapils, caramalt in pale beers along with carafa, chocolate and black malt in dark beers will add some more body. Lactose can add body and sweetness too and can’t be fermented by brewers yeast.

It should be noted though that a high amount of adjunct malt can make a beer too heavy and thick, so a balance is needed.

Mash & Boil

Mash temperature has an effect on the fermentability of the wort. Put simply, mash around 69°C and the beer will be sweeter, mash around 60°C and the beer will be dryer. Considering a low ABV beer will have less malt, it makes sense to mash higher to give the beer more body whilst stopping the yeast from fermenting all the sugars, resulting in a lower ABV beer.

Mashing for a shorter amount of time will also reduce mash efficiency as there will be less time for starches to convert to sugar. There are many disagreements online as to how long starch conversion takes, with some brewers claiming conversion happens in as little as 15 minutes. If this is a route you want to go down, I’d recommend some experimentation by stopping the mash earlier and earlier each time and seeing when the gravity is at the right point.

Alternatively, if you have a good idea of what your average mash gravity is like you can take a reading at various times throughout the mash until it’s at the level required.

Similarly the boil should be short so as not to boil away flavour compounds or concentrate the wort.

Yeast

One of the main sugars in wort is maltotriose, and there are a few yeasts which can’t ferment that sugar. That will leave a sweeter beer with a lower ABV. Lallemand’s Windsor yeast and Fermentis’ S33 both can’t ferment maltotriose. They’re both excellent yeasts suitable for a range of different beers and go well making low alcohol beers.

There are non-saccharomyces yeasts which are used by some commercial breweries to make low alcohol beer due to their inability to either ferment maltose and maltotriose or survive alcoholic conditions. As of writing they are quite rare to find in the homebrewing world though.

Whether or not you’re looking to lower the alcohol intake, a low ABV beer is a different sort of challenge every brewer should take on at some point. In some ways, it’s a lot harder to make a great low ABV beer than a high gravity one. Let us know how you got on with your low alcohol brew!