We've already taken a peek into Belgium's rich brewing culture, but we simply couldn't ignore the weird and wonderful sour side of Belgian beer. Spoiler alert: there's going to be lots of wild yeast floating around!

Lambics are traditionally brewed in the Brussels area, with a grain bill which is part malt, part wheat. The lambic brewing process is quite different to other beers, as the wort (unfermented beer) is left open to the air so it can be infected by the wild yeast in the environment, which start it fermenting. The yeast is also thought to live in the brewery's wooden timbers, vessels and barrels. Sounds grim, but it's a good thing!

In most beers, infection by yeasts such as Brettanomyces would be seen as a bad thing, but lambic brewers prize the resulting dry, funky and tart notes that sour beer fans adore. Fruit lambics such as Timmermans Strawberry, Kriek and Framboise, Lindemans Framboise and Liefmans Fruitesse are popular, and Timmermans even brew a seasonal Pumpkin Lambicus! Young and old lambics are often blended together and bottled for a second fermentation, resulting in dry, sharp gueuze like Lindemans Cuvee Rene.

Another popular sour Belgian style is Flanders red ale. Brewed with red malt and fermented with Lactobacillus, this vinous style has a lactic tang and is often aged in oak barrels to allow its sour, tannic character to develop. The fruity sweet and sour character of Rodenbach has its delightfully sharp acidity intensified and deepened in Rodenbach Grand Cru, while Brouwerij Verhaeghe Duchesse de Bourgogne is marvellously complex and tart. Less widespread but still brewed is the Oud Bruin style, similar to Flanders red but darker and less sour.

So there you have it: wild yeast isn't always the enemy of beer! Even one of the few Trappist breweries, Orval, uses Brettanomyces to ferment their beer, so why not check out the sour side of Belgian brewing? Cheers!

- Rowan