Classic lagers or ancient ales?

The "brothers" of the Tasman Brewing Company

It never ceases to surprise me how many people – often beer drinkers – don't understand the difference between ales and lagers, beer's two major families.

Contrary to popular belief, you can't determine a beer's parentage by its colour. Ales and lagers both range from the palest shade of yellow to inky black and everywhere in between. The difference is determined by the type of yeast selected by the brewer and the temperature and environment in which fermentation occurs.

When a brew ferments in an open vessel, it warms and develops a thick foaming head. By collecting the foam – which contains millions of yeast cells – and adding it to the next batch, medieval brewers found they could achieve consistent fermentation. The effect of their action was to isolate and preserve the most prolific yeast strains. This technique of "top fermentation" is still used by brewers of most wheat beers and all true ales, porters and stouts. Working anywhere from about 18 to 30 degrees Celsius, "ale" yeasts typically produce fruity and spicy aromas and flavours.

English ales often have a fruitiness reminiscent of orange, strawberry or dessert apple, while Belgian ales often exhibit suggestions of clove, white pepper and vanilla. All these flavours are the result of fermentation with ale yeasts. In Germany, Bavarian brewers isolated a family of ale yeasts that produce banana, bubblegum and clove flavours in their wheat beers.

German brewers were also responsible for the development of lager brewing. Before the advent of refrigeration, the atmosphere during summer was so alive with wild yeasts that fermentation became uncontrollable. Brewers in Bavaria found that by storing their beer in the icy caves of the Alps, they could preserve their beer by making the yeast "hide" at the bottom of the vessel.

Be they black, brown, copper, bronze or gold, all bottom-fermented beers are known as lagers, a term derived from the German verb lagern, meaning "to store". Germany's classic lagers are fermented at about 5degC to 9degC and gain their clean, rounded, flavours only after a lengthy cold maturation of several weeks or even months at about 0degC.

Today golden-coloured lager beers dominate the world beer market, but most are fermented much warmer and given a shorter maturation. Here in New Zealand, our largest brewers employ lager yeasts in almost all their beers regardless of colour or name. Tui (which is labelled an East India Pale Ale) and Speight's (Gold Medal Ale) are, in fact, both amber coloured lagers.

There's also a third family of beers. Thousands of years before the discovery of the existence of yeasts, brewers knew only that if they left a sugary solution of grain and water in an open vessel, it would in time turn, into beer. We now know that these fermentations were triggered by wild yeasts that were either airborne or resident in the brewery's structure or vessels. This seemingly haphazard way of making beer suggests the brewer has little control over the choice of yeast or the fermentation, creating a technique which is known as spontaneous fermentation.

Today spontaneous fermentation in brewing is rare. Its most famous exponents are a handful of artisanal producers in and around Brussels, in Belgium. The style of wheat beer they produce is called lambic and is usually acidic and wine-like, tasting like a cross between beer, cider and dry sherry. In order to soften the intensity of these ancient beers and broaden their appeal, lambic brewers traditionally re-ferment them by adding seasonal soft fruit like cherries (kriek) and raspberries (frambozen).

Most of the lambic beers found in New Zealand are heavily sweetened, but look out for drier, more traditional, examples from the likes of Boon, 3 Fonteinen and Cantillon. They're beers all right, but they're unrecognisable as such to most lager drinkers!

Cheers!

- The Marlborough Express

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