Sour Beers: Do They Contain Wheat?

Sour beer is a broad category of beer that is intentionally soured or acidic. Some sour beer styles contain wheat, while others do not. Belgian lambic and gueuze sour beers traditionally contain 30-40% unmalted wheat. Berliner weisse is another classic wheat-based sour beer. However, many American sour styles like gose and American wild ales are brewed with barley and do not contain wheat.

Lambic, Gueuze, and Berliner Weisse are traditional wheat-based sour beers

Lambic is a type of beer brewed in the Pajottenland region of Belgium, southwest of Brussels, and in Brussels itself since the 13th century. Lambic differs from most other beers in that it is fermented through exposure to wild yeasts and bacteria native to the Zenne valley, rather than exposure to carefully cultivated strains of brewer's yeast. Lambic is generally brewed from a grist containing about 60-70% barley malt and 30-40% unmalted wheat. The wort is cooled overnight in a shallow, flat, metal pan called a coolship, where it is left exposed to the open air so that more than 120 different types of microorganisms may inoculate the wort.

Gueuze is a type of lambic beer. It is made by blending young (one-year-old) and old (two- and three-year-old) lambics. Because the young lambics are not yet fully fermented, they undergo secondary fermentation in the bottle and produce carbon dioxide. Gueuze is given at least a year to carbonate in the bottle but can be kept for 10-20 years. Like lambic, gueuze contains unmalted wheat as it is a blend of young and old lambics.

Berliner Weisse is a low-alcohol German wheat beer. Traditional recipes call for at least 50% malted wheat in the grist, along with pale barley malt. Some versions use up to 70% wheat. The high proportion of wheat gives Berliner Weisse a hazy, light gold colour and provides proteins for a frothy head. It also contributes to the beer's characteristic tart and acidic palate. Berliner Weisse is traditionally accompanied by fruit syrup, such as green woodruff or a berry syrup, that is added at serving for a shot of sweetness and additional complexity.

American sour styles like Gose and Wild Ales are brewed without wheat

Wheat is a common ingredient in many sour beers, adding haze and cloudiness, enhancing acidity, and providing nutrients for fermentation. However, not all sour beers contain wheat, and this includes American sour styles like Gose and Wild Ales.

Gose is a German ale that traditionally contains wheat, but contemporary American Gose beers are brewed with 100% barley malt and do not contain wheat. The use of wheat is not a requirement for this style of beer, and brewers may choose to use small amounts of raw or flaked wheat or exclude it entirely.

Wild Ales are a diverse category of beers fermented with wild or natural yeasts, resulting in a range of funky flavours. While some Wild Ales may contain wheat, it is not a mandatory ingredient. American Wild Ales, in particular, can be brewed with a wide variety of ingredients, including domestic 2-Row barley and various other grains and adjuncts. The choice of ingredients depends on the brewer's preferred recipe and the characteristics they aim to achieve.

It is important to note that while American sour styles like Gose and Wild Ales are typically brewed without wheat, other sour beer styles such as Belgian Lambic, Gueuze, and Berliner Weisse traditionally contain significant amounts of wheat. These beers are known for their hazy appearance and tart flavour, which is enhanced by the presence of wheat.

In summary, while wheat is commonly used in sour beers to add body and enhance certain characteristics, it is not a requirement for all sour beer styles. American sour styles like Gose and Wild Ales are often brewed without wheat, showcasing the flexibility and creativity of brewers in crafting unique and distinctive sour beers.

Sour beers are made with wild yeasts and bacteria like Lactobacillus

The use of wild yeasts and bacteria in sour beers is a result of traditional brewing methods, where the starter used from one batch to another often contained wild yeast and bacteria. This is in contrast to modern brewing, which is done in a sanitary environment to prevent the intrusion of wild yeast.

Sour beers can be made through either wild or mixed fermentation, where multiple yeasts and bacteria work together to create the unique flavour profile. While Saccharomyces, or brewer's yeast, is responsible for fermenting all clean beers, sour beers typically use a combination of wild yeasts and bacteria such as Brettanomyces, Lactobacillus, and Pediococcus.

Lactobacillus is a crucial component of sour beers, as it rapidly produces lactic acid, lowering the pH and creating a sour taste. This process, known as kettle souring, is commonly used in German-style sour beers like Gose and Berliner Weisse.

In addition to Lactobacillus, Pediococcus is another common lactic acid-producing bacteria used in sour beers. Pediococcus takes longer to lower the pH of the beer, allowing time for the primary yeast strain to complete its fermentation. However, Pediococcus can produce undesirable buttery flavours and is therefore often used in combination with Brettanomyces, which helps to eliminate these off-flavours.

The combination of wild yeasts and bacteria in sour beers creates a complex and unique flavour profile that has led to their increasing popularity. While the use of Lactobacillus is essential to the sour beer style, the specific combination of microbes used can vary depending on the brewer's preferred recipe and the characteristics they want to achieve.

Sour beers can be made through kettle souring or mixed fermentation

Kettle souring is a modern technique that allows brewers to rapidly sour unfermented wort in a matter of days, usually taking 24 hours to 3 days. After creating the wort and conducting a brief boil for sanitation, the wort is cooled to 75–95 °F (24–35 °C) and a cultured strain of pure lactobacillus is introduced. Lactobacillus consumes sugars in the wort and transforms them into lactic acid, providing the tart flavor characteristic of sour beers. Once the desired level of sourness is achieved, the wort is boiled again to kill off the lactobacillus, and the beer is then fermented as usual. Kettle souring is a popular method for brewers who do not want to wait for the long aging period of traditional sour beers, which can take up to 24 months. It also allows for more hop-forward sour beers since lactobacillus is sensitive to isomerized alpha-acids. Examples of beers that are made through kettle souring include Sour IPAs, Sour Stouts, and Milkshake Sours.

Mixed fermentation, on the other hand, is any fermentation that consists of a combination of Saccharomyces (brewer's yeast), Brettanomyces (wild yeast), Lactobacillus (lactic acid bacteria), Pediococcus (lactic acid bacteria), or other unconventional microbes. There are two main styles of mixed fermentation: with lactic acid bacteria (Lactobacillus and/or Pediococcus) and without lactic acid bacteria. Mixed fermentation sour beers are characterized by their higher acidity and tart flavor due to the production of lactic acid, and they generally fall within a pH range of 3.0-3.7. The primary fermentation is typically conducted by Saccharomyces, which achieves the majority of attenuation, and then a mixed culture of Brettanomyces, Lactobacillus, and Pediococcus is introduced for a secondary fermentation. This secondary fermentation converts the remaining complex carbohydrates, increasing the degree of attenuation and lowering the pH of the beer. The beer is then aged, which can take several months to a year or more, depending on the desired result. Traditional Belgian sour beer styles such as Lambic, Gueuze, and Flanders Red Ale are made through mixed fermentation, as well as some modern American wild ales.

Sour beers are known for their refreshing, acidic taste

The use of souring agents and wild yeasts gives sour beers their characteristic lemony, almost yoghurt-like tartness, with a hint of funkiness. The acidity in sour beers can range from a subtle tang to an outright acid-like, vinegar flavour. The intensity of the sourness depends on various factors, including the type of organic acids present, carbonation levels, alcohol levels, and the use of fruit or barrels during ageing.

While some sour beers are brewed with barley and do not contain wheat, others do include wheat in their recipes. Traditional German and Belgian sour beer styles, such as Berliner Weisse and Belgian Lambic, often contain wheat. These wheat-based sour beers contribute to a cloudy, hazy appearance and enhance the acidity and tartness of the beer. The wheat also provides proteins for a thick, frothy head, as well as nutrients for microbe growth during ageing.

The inclusion of wheat in sour beers is not mandatory but can lend desirable qualities to the final product. Brewers have the flexibility to choose between wheat and barley, or a combination of both, to achieve their desired flavour profile, appearance, and fermentation properties.

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