Ways to Brew Low-Alcohol and Non-Alcohol Beers

Before jumping into a review of some of the methods used to produce no- and low-alcohol beers, so-called NABLABs where NABs (non-alcohol beers) contain less than 0.5% ABV and LABs (low-alcohol beers) contain greater than 0.5% ABV, I want to provide a sort of spoiler alert; there are not a bunch of great methods for homebrewing NABLABs. However, because of the creativity of homebrewers, folks will likely come up with some great ways in the near future by riffing on newer commercial techniques to fill this void.Alcohol Removal

One common strategy used for decades in the production of NABLABs is removing alcohol from relatively normal beers. Because some aromas are lost in the process and the flavor balance of the beer changes, beers intended for alcohol removal are brewed with the end-goal in mind, hence the “relatively normal” description. The two most common ways to remove alcohol from beer are vacuum distillation and reverse osmosis (RO).

Most beer drinkers who have consumed a variety of NABLABs have probably come across beers with a cooked or burnt flavor. The early distillation methods used to produce NABLABs worked for alcohol removal, but many of these systems were a bit rough around the edges and made for some interesting flavors. Beer distillation is much more advanced these days and current hardware combines low-temperature, vacuum distillation with aroma recovery to produce some really nice tasting beers.

These systems feature a tall column filled with a cleanable packing material, a beer inlet and outlet circuit, and a gas stripping circuit. In simple terms, beer is pumped into the top of the column and allowed to flow down through the packing while an inert stripping gas is introduced into the bottom of the column and removed from the top along with the alcohol. The beer temperature in these systems is about 110 °F (43 °C) at 100 mbar (10% of atmospheric pressure). If you have sampled a wide selection of NABLABs from the market, chances are high that you have tasted brews made using this method.

Many brewers know about reverse osmosis water treatment, where nearly pure water flows across a membrane, leaving a concentrated retentate stream on the supply-side of the membrane and allowing for the removal of this concentrated water stream in the reject stream. The same basic technology can be used to remove alcohol and water from beer to produce NABLABs. When RO is used to dealcoholize beer, water is added back to balance the water removed with alcohol.

Arrested Fermentation

Some brewers figured a great way to make NABLABs is to greatly minimize ethanol production using various arrested fermentation strategies. Some of these beers are taken through an alcohol removal process, but are different from the “brew normal beer and remove the alcohol” strategy because of the very low alcohol levels produced by the method. One drawback to arrested fermentation is a worty note often associated with these beers. In my opinion, that critique is not a show-stopper because today’s beer consumer has developed a more diverse palate and beer produced from arrested fermentation could easily be spiffed up by adding acids and flavors to make for some interesting interpretations of trending beer styles.

This is one method that could be performed at home because the principle is pretty simple; stop fermentation by rapidly chilling beer before much alcohol is produced, remove the yeast by centrifugation (not at home, of course) and/or filtration, and stabilize the product by pasteurization. The last step could be replaced by using a combination of sorbate and sulfite or the beer could be kept very cold in a keg and carefully monitored by frequent drinking to spot signs of any re-fermentation. If this method is used, do not attempt skipping the filtration step, keep all parts of the dispense system in the cooler, and DO NOT bottle these beers. A cobra-head faucet is the best choice here. And make sure the beer pH is below 4.6 to prevent the growth of Clostridium botulinum spores.

Maltose-Negative Yeast Strains

Some yeast strains are able to ferment glucose, but not maltose or maltotriose. These yeasts are known as maltose-negative strains and offer a relatively simple way of producing low-alcohol beers. Like beers produced using the arrested fermentation method, these brews contain fermentable sugars, and also are likely to require pH adjustment to bring beer pH below 4.6. The yeast companies selling maltose-negative yeast strains advise brewers to pasteurize these beers after packaging.

Homebrewers are going to do what homebrewers do and give these strains a try by hitting up commercial brewers for yeast. Just keep your eyes open and DO NOT bottle beer containing fermentable sugars.

Let’s take a break from the process and dig a bit deeper into the carbohydrate profile of wort. It goes without saying that there are multiple factors influencing carbohydrate profile, but we can look at values for typical wort produced with-out special malts or adjuncts using the standardized congress mash method. We can see from Figure 1 that typical wort contains about 15% glucose.

When maltose-negative yeast strains like Saccharomyces cerevisiae var. chevalieri are pitched into 12 °P (1.048 SG) wort, the maximum glucose they can consume is about 19 grams of glucose per liter of wort (1 liter x 0.12 kg extract/kg wort x 1.048 kg wort/liter x 0.15 kg glucose/kg wort x 1,000 grams/kg). When glucose is fermented, it is converted to ethanol (51% by weight) and carbon dioxide (49% by weight). In other words, maltose-negative yeast produce beer with about 1% ABV when the wort OG is 12 °P (1.048 SG). If the goal is beer with < 0.5% ABV, simply lowering the OG to 6 °P (1.036 SG) does the trick.

So, there you have it, Nick. Those are some of the most common methods to remove alcohol from beer. I am neither advocating nor opposing any of these methods for consideration at home. Just trying to answer your question in basic terms. But . . . if someone wants to play around with any of these commercial methods and report back about the results, we certainly would love to hear about the trials!

And, for the record, be sure to measure the pH of any homebrewed NABLABs and adjust the pH below 4.6 if required. This is a critical pH in the world of food processing and distinguishes high-acid foods (pH<4.6) from low-acid food (pH>4.6). The other very important safety reminder is packaging; DO NOT bottle or can beers that contain fermentable sugars unless the beers are pasteurized in the package.

Response by Ashton Lewis.