Climate change wreaks havoc on Belgian beer

One of the oldest styles of Belgian beer could soon change due to rising temperatures caused by climate change.

Lambic is a type of beer fermented through exposure to wild yeasts and bacteria native to the Zenne Valley in Belgium, rather than the traditional brewer's yeast often used in beers. This method gives it a distinctive flavour with a mouth-puckering sour aftertaste.

Brewers depend on the period between October and April, when nighttime temperatures fall between 8 and –8 C. But as temperatures around the world rise, the window for lambic production shrinks.

A new study led by brewers in Belgium shows the period for ideal production is now only 140 days, compared to 165 days a century ago.

Unwanted bugs and bacteria

Jason Meyer, co-owner of Driftwood Brewery, makes a North American lambic at his facility in B.C.

"The first step in lambic production [in Belgium] is they take the wort — the unfermented beer — and they put it in something called a coolship — a big, open vat, which allows the wort to cool down to fermentation temperature just because of the ambient temperature," said Meyer.

But rising ambient temperatures cause problems by attracting different and unwanted bugs and bacteria.

As the brewing window shrinks, supporters of the style worry authentic Belgian lambic will become harder to find and more expensive.

Solutions to the problem do exist. One idea is to move the breweries, but some of Belgium's most famous breweries have existed for centuries in one location and moving to find a slightly different environment isn't easy.

One of Belgium's most famous lambic makers is Cantillon, based in Brussels. Cantillon produces about 400,000 bottles a year and much of it ends up on store shelves in Canada. In the future, the brewery says it will either have to change production methods or move farther north to Denmark or Sweden.

'Emulating the style and stealing the name'

Changing production methods would mean adopting the approach that Meyer and other North American sour beer makers use.

Rather than using the coolship method, most North American brewers put the lambic into wine barrels and leave it to ferment and mature for one to seven years.

Sour beer purists in Belgium argue this isn't genuine lambic because North American brewers inoculate the brew with pre-selected microbes, instead of allowing more than 120 different types of micro-organisms do the work naturally.

But Meyer argues you'd be hard-pressed to find a difference.

"There is inherent value in it because it's traditional. Whether or not it's necessarily better, that's something brewers will debate amongst themselves," said Meyer.

Adam Harbaugh, one of the study's authors, said it's not better.

Referring to the brew as a lambic outside of the Pajottenland and Zenne Valley in Belgium is a huge cultural issue.

"There is no one in North America producing lambic," Harbaugh said in an email to CBC. "Anyone purporting to make lambic in Canada or [the] U.S. is only emulating the style and stealing the name outside of the cultural tradition and heritage of lambic producers."

Still, if Belgian brewers lose the perfect climate for a traditional brewing method, they may have no choice but to turn to North American ways.