How do you brew beer without the booze?

Found yourself reaching for a non-alcoholic beer recently? More and more of us are.

And gone are the days of just one or two options, as New Zealand’s breweries get in the game – producing non-alcoholic versions of all the craft beer options.

But with alcohol fermentation such a key part of the traditional process, how do brewers deliver the complex flavour of beer without it?

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This year, the Brewers Guild of New Zealand reported the volume of low- and no-alcohol beer consumed has increased 750 percent since 2019.

The stats from Wellington’s Garage Project reflect this. They might release close to 200 different beers in a single year, but just one beer makes up about 12 percent of their production, says Dr Peter Bircham: their original non-alcoholic offering.

Bircham is the head of research and development at Garage Project and specialises in technical brewing puzzles. He’s got a background in molecular biology, a history of home brewing, and research experience in Belgium developing a non-alcoholic beer yeast strain.

He’s excited about the challenge presented by brewing non-alcoholic beer that tastes good.

“It's all exploratory. There's so many lessons to be learned and find our own new way of dealing with these things. So it's a pretty exciting space to work in,” he says.

Traditional brewing involves malted grains (or malt), hops, water and yeast. Flavour is developed by tweaking malt and hop additions, temperatures, and pressure through various steps in the brewing process – but alcohol fermentation is a key part of developing the final taste.

During fermentation, yeast breaks down the main sugar in beer – called maltose – and converts it to alcohol. But the yeast also works biochemical magic on other sugars and different flavour compounds within the liquid – removing undesirable ones and enhancing others.

This is not a lucky accident.

“It’s actually one of the most domesticated organisms” says Bircham.

Across centuries of brewing, humans have moulded the beer yeast genome through continuous re-use, a form of directed evolution. Its DNA is now very different to wild yeast, with some genes removed and others duplicated.

There are two main options to make to non-alcoholic beer.

The first is to brew the beer as normal and then strip out the alcohol.

Vacuum distillation can evaporate off the alcohol, or it can be filtered out using reverse osmosis – but both require expensive machinery, which your small-to-medium craft brewery just can’t fork out for. These processes can produce 0.0 percent beers, but they also strip out flavour compounds, some of which get added back in afterwards.

The second involves altering the fermentation process so the alcohol never gets produced in the first place.

At Garage Project, they buy in a strain of non-alcoholic yeast to do this.

This yeast is unable to break apart the maltose sugars, meaning it can’t covert them to alcohol. Instead, it converts the small amount of glucose in the mixture, resulting in the <0.5 percent alcohol by volume that can be labelled non-alcoholic in New Zealand.

But it’s tricky to work with, says Bircham, and costly.

“There [are] really special conditions required for storing these yeasts and working with them. Unlike normal beer, you can't repitch them because there's too high a risk that you'd get a normal beer yeast in there as well… So the yeast cost is actually a lot higher in non-alcoholics because you're using new yeast every time and using specialised yeast.”

It’s not just the yeast that’s different.

Because the maltose won’t get broken down, Bircham must carefully consider what goes in the original mix. Alcohol helps with the sweetness and mouthfeel of beer, and some of the extra maltose left behind in the non-alcoholic beers helps to compensate for this. But too much and they end up tasting too sweet.

Plus, the alcohol produced in fermentation, along with the acidity of beer, normally helps to protect the beer from nasty bacteria growing inside it. In the absence of the alcohol protection, the finished beer becomes a sugar-rich liquid ripe for bacteria to grow in. Hence why Garage Project also take the additional step of pasteurising all their non-alcoholic beers.

Bircham also holds an adjunct research position at Te Herenga Waka, Victoria University of Wellington. With collaborators there, he’s been exploring the possibility of creating a new non-alcoholic yeast strain, either from wild native New Zealand yeast, or from ‘reverse domestication’ of beer yeast.

By blocking the yeast’s ability to break down maltose, they’ll attempt to push evolution in the direction they want, to create a new strain with potential for commercial opportunities.

Alongside the lab efforts, Dr Fandy Tjiptono, of the school of marketing and international business, is running a survey to better understand why people choose non-alcoholic beer. Is it for short-term hangover relief or long-term health goals? Is it a trend, or here to stay?

Bircham is keen to learn the answers – but what they're hearing from their customers has been positive so far.

“It's amazing how many people just say, ‘we love that these are available now’. We get far more feedback around these kind of things than we do some of the other alcohol beers. People just really appreciate that they've got serious non-alcoholic options now.”

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