Every few years a different style of beer becomes the new darling of home brewers and takes over the discussion of the craft beer world.
For a while it was the IPA, and there was a time that everybody was talking about and brewing Russian Imperial Stouts. There was even a period of Belgian beers.
Lately the trend has been sour beers.
Sour beer historically has been difficult to find and expensive to buy in the United States, so many craft beer lovers are unfamiliar with it.
1. What Is Sour Beer?
Sour beer is specifically brewed and fermented to have a sour taste, which can range from the slightly tart to the very sour. Some varieties even described as having qualities similar to the face-puckering candy “Warheads”.
These beers have a high acidity and improve with age over the course of several years.
2. What Are the Characteristics of Sour Beers?
The color of sour beers ranges from a pale golden color to brown. The hop flavor in these beers is usually subdued, coming in at only 20-40 IBUs. The carbonation is usually very noticeable, and the mouthfeel of the beer is light to medium.
There is a large range of alcohol contents between sour beers, but they usually fall between four and nine percent alcohol by volume. The beer styles most often associated with sour beers are the Flanders red ale and the Belgian lambic.
3. How Are Sour Beers Made?
There is a heftier price tag for sour beers because they are very difficult to make well, almost impossible to reproduce consistently, and take a long time to brew and ferment.
Sour beers are brewed like a normal beer but they are typically aged in a wood barrel, often a wine barrel. A strain of yeast called Brettanomyces is most often used to give the beer a unique flavor, and a couple of specific strains of bacteria are added to help the beer acquire the sour flavor.
Some brewers will even expose their beer to the outdoors to allow wild strains of yeast to work on the beer. The beer takes a long time to ferment and pick up the sour taste – at least six months, but more often between one and three years. The brewmaster will taste the beer periodically during that time and can make adjustments to the flavor by adding different strains of bacteria.
4. Why Are Wood Barrels Used to Make Sour Beers?
The wood barrels are important to the sour beer making process. The barrels contain bacteria from the wine that they had previously held, and this bacteria aids in the aging and souring of the beer.
The wood allows some air to permeate and diffuse into the barrel, which feeds the Brettanomyces yeast and helps it to do its work on the beer.
5. Why is There Inconsistency In Sour Beers from One Batch to the Next?
There are so many variables at play in sour beers – the beer ingredients, the bacteria that are added, and the bacteria in the barrels, among others – that it is tough to reproduce a sour beer consistently. Even within the same batch different fermenting barrels will produce different flavors.
The brewmaster can make adjustments with bacteria, but even then some barrels from every batch have to be dumped because they simply do not turn out well. This is what drives up the price of sour beers and makes them discouraging for breweries to produce.
Even with all of the difficulties in producing sour beers, and the long wait from brew date to enjoyment date, we are seeing and increasing demand for this style and an increased supply from breweries as a result.
Have you tried a sour beer? Which is your favorite?