What’s Up With Sour Beer?

There’s nothing like ending the day with a pint, or two. You might like to sit down to a rich, flavorful stout, or maybe you’d prefer a hoppy, citrusy India Pale Ale, or something with more malty like a brown or red ale. There is a wide variety of beer in the world, with an incredibly diverse range of taste, texture, and aroma. It’s that feeling of anticipation and discovery that makes us look forward to the next offering at our local brewery. But what about sour beer?

There aren’t a lot of sour beer offerings out there, and if you haven’t had one, you’ll find that they definitely have a distinctive taste.

Most people either love them or hate them. Some say they are an acquired taste. But what are sour beers?

At one time sour beers were mostly the domain of Belgian brewers. There were sour beers brewed in other places, but the Belgians were the ones best known for sour brews

Sour beers are sometimes also referred to as open fermented beers. This comes from the practice of allowing wild yeast strains into the brew during fermenting. These wild yeasts can be found on fruit skins, and also floating around in the air. By leaving the wort (or unfermented beer) exposed or “open” to the air during fermentation, allowing wild yeasts to find their way into the brew. Most brewers work hard to control every aspect of their brewing process, especially the types of yeasts used, in order to produce a specific- and consistent taste. Allowing wild yeast in during fermentation can result in wild results.

There are several ways that brewers can develop sour flavors in their brews. And while a small number of brewers use the original method, other techniques have been developed.

There are two basic options available for brewers hoping to use yeast to create a sour brew. The first option is to use aging barrels that already have wild yeast in them. This is the way brewers did it in the beginning, and you’ll find this method used mostly by traditional brewers still operating in Belgium.

The second option is to intentionally introduce a particular strain of yeast to the mix known for creating the desired flavors, resulting in a tart, sour brew. This can be done by simply leaving the wort exposed to the air, to allow wild yeasts to find their way into the brew. Another way to introduce a strain of wild yeast is to use different types of fruit during the aging process, creating a secondary fermentation. Not only does the fruit add its unique flavor characteristics to he beer, but it also brings with it the wild yeasts found on its skin, which will then feed on the remaining sugars in the brew as well as the additional sugars from the fruit. Cherries are a popular fruit for this. Of course fruit can also be used mostly for flavoring by adding tartness to a brew while also increasing its sourness. Apricots are favorites for this. Of course in todays market, brewers can also just purchase the desired strain of yeast needed to impart the desired sour flavor and introduce it directly to the brew- but where’s fun is that?

Naturally there are problems when using wild yeasts during the brewing process. Cross contamination is a very real threat and can ruin a good batch of beer, so brewers making use of these particular yeast strains must keep their sours far away from their regular brews, some even house their sour beer in a completely separate building.

One of the most important aspects of brewing sour beers (besides the flavor) is that they require a much longer aging process. While ordinary beers can be age for as little as a few weeks, sour brews need to age for a much longer time, some up to three years. That can represent a significant investment for the brewer in time, equipment and space for brewers, especially if the investment doesn’t pay off. Even if the beer comes out exactly the way they wanted, some craft brewers may find that these beers are really only enjoyed by a few true sour beer lovers.

Almost any type of beer can be made sour (hence the fear of cross contamination). All you need is the right bacteria and a little bit of time. However, there are three types that are known specifically as sour brews: Flemish ales, Guezes and Lambics. Of the three, lambics are probably the most well known for their sourness. However, both German and American style sour ales are beginning to grow in popularity in the growing craft beer market.

While the name “sour” can be a turn off, you’ll find that the refreshing, tart nature of these brews can make a world of difference in your own drinking enjoyment, and can even bring non-beer lovers into the craft beer fold.

If you’ve never had a sour beer, you owe it to yourself to give them a try. You may just discover the best beer you’ve never had.