One group of beers that has become very popular amongst craft beer conisseurs recently is sour beers. Sour beers undergo part/all of their fermentation with strains of wild yeast or bacteria, which impart a tart, acidic sour flavor to the final beer. This flavor is considered “off” in most beer styles, many homebrewers have an experience with a batch of beer that was spoiled due to improper cleaning or sterilization. There are a number of Belgian ales that are made by intentionally exposing the beer to these microorganisms, taking advantage of the unique flavor profiles created. The flavors in sour beers can be difficult to control and they are often aged for long periods of time, so it takes special care to brew great sours. I admittedly have very limited experience with sour beers. I have tried a few, but I am far from being an expert. I thought it would be a fun exercise to start trying some sours and document the journey on this blog. My friends at Craft Beer Cellar in Newton were more than happy to recommend a few “introductory” sour beers for me to start with. I’ll refrain from giving the beers a score until I get a little more experience with each sour style.
One common type of sour beer Oud Bruin (“old brown”) or Flander’s Brown Ale, originally from the Flemish region of Belgium. Oud Bruin beers typically undergo long secondary fermentations in stainless steel vessels with the addition of wild yeast or bacteria, giving them an often mild but distinct sour character. One popular Oud Bruin is Petrus, brewed by Brouwerij De Brabandere. Petrus Oud Bruin is made with a blend of aged sour beer and fresh “sweet” beer. It is sold in MA in 4-packs of 11.2 oz bottles.
Petrus Oud Bruin pours a clear caramel brown with a solid and sustained off-white head. The smell is pretty mild with some medium malt and a little funk. The taste starts with the malt flavor, a touch of caramel and some baked bread, similar to the malt profile in a very mild English brown ale. The yeast flavors are present but not overwhelming, some acidity with a little cherry and lemon flavor. There is very little hop flavor, but the tartness from the fermentation acts as a solid counterpoint to the malt sweetness. The finish is pretty clean, with just a hint of residual sourness on the tongue.