With the fourth wave of the pandemic overwhelming our health care system, I have retreated once again to the comforting seclusion of my windowless booze cave in the basement, peering through the dusty corners in search of long-forgotten tipples to wait out these increasingly apocalyptic days in hermetic solitude.
I made a welcome discovery of a cache of sour beers tucked away on a dusty shelf, which were calling out to me to be consumed. For those not familiar with the style, sour beers have an intentionally acidic or sour taste due to the introduction of certain yeasts or bacterial cultures during the fermentation process.
My first exposure to sour beers was in the carefree pre-pandemic days of 2013, while vacationing in Belgium, also known as the beeriest place on earth, with over 500 distinct beer styles calling Belgium home, most of which are entirely unfamiliar in North America.
Lambics are perhaps the most common sour beer style from Belgium, produced along a 100km stretch of the Senne Valley, with the eponymous River Senne flowing through the center of Brussels, making it an important transportation route in centuries past.
Lambic beers are fermented with naturally occurring airborne yeasts, so may differ from batch to batch. The particular airborne yeast strain used to ferment Lambic beers is called Bretanomyces Bruxenellensis, and occurs naturally only in the Senne Valley near Brussels, making this a highly regional beer style.
The taste of Lambic beer can be off-putting to the novice beer drinker, particularly those raised on a steady diet of Coors Lite. While the wild airborne yeasts can make the taste vary widely from one batch to the next, the primary flavour of a Lambic is one of sour fruit and spice.
To make the sour taste more palatable, the beer will be aged, then blended in equal parts from barrels aged for one, two, and three years prior to bottling.
The youngest barrel in the blend will still contain live yeast, so a secondary fermentation occurs in the bottle, which provides extra depth and complexity, leading to flavours of rich dried fruit.
While Lambics have been exported the world over, with many examples available here in Alberta, the limited region that the yeast is available can make Lambics hard to find.
Lacking that magical Belgian yeast here in Alberta, our locally produced sour beers tend to be kettle soured, meaning a carefully measured sample of the same lactobacillus bacteria found in yoghurt is added to the brew kettle before boiling the wort. The bacteria is killed during the boiling process, leaving behind a tart and sour flavour that can be controlled by the attentive brewmaster.
Blindman Brewing in Lacombe has long been producing sour beers in addition to their other offerings, with the Dry Hopped Kettle Sour available year-round. The pH level has been precisely controlled for just the right amount of tartness, with loads of aromatic hops added near the end of the boil giving citrus and tropical notes on the nose.
The Establishment Brewing Company in Calgary is another purveyor of sour beers, using carefully propagated wild yeast strains that they age in oak barrels using old world techniques. Differences in the bacteria strains in each barrel mean that every release is unique, with most of their small batches only available by the pint in the taproom. The Jam Rock Blackberry Sour is one of the few releases that do make it into cans, so keep your eyes open at your local beer merchant. This is a kettle soured brew, with additional tartness from a heap of blackberries added to the brew kettle, then balanced with vanilla bean to produce a jammy finish.
A little closer to home, Origin Malting & Brewing in Strathmore have put out a few seasonal sour brews, most recently the Country Orchard Sour in the pre-pandemic summer of 2019, which I remember drinking with great gusto on their patio in those carefree times. A wild yeast strain was used in this brew, together with some lactobacillus in the kettle to produce an ale with strong notes of crabapple. Origin has not produced another one-off sour batch since then, but hope springs eternal!
If you would like to give sour beers a try, ask your friendly neighbourhood booze merchant for advice, or visit one of our many fine local brewers.