Sour beer is a broad style of beer that is intentionally soured or acidic. The sour flavor in these beers comes from bacteria and wild yeasts that produce acids like lactic acid during fermentation. Two common methods used to produce sour beers are kettle souring and mixed fermentation.
Quick Answer
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.
What is Sour Beer?
Sour beer refers to any beer that intentionally has pronounced tart, acidic flavors. The sour taste comes from increased levels of acids like lactic acid, acetic acid, and citric acid. These acids are produced during fermentation by wild yeast strains and bacteria.
Traditionally, most sour beer styles originated in Germany and Belgium. However, craft brewers around the world now produce all kinds of sour and wild ales. Some classic examples include:
- Lambic – Spontaneously fermented Belgian ale
- Gueuze – Blended lambic beer
- Flanders red ale – Oaky reddish sour beer from Belgium
- Berliner weisse – Low-alcohol German wheat beer
- Gose – Tart and salty German ale
- American wild ale – Mixed fermentation sour beer using wild yeast and bacteria
While traditional sour styles have a long history, the variety of sour beers has exploded in recent years. Brewers are constantly experimenting with new recipes, aging methods, fruit additions, and wild fermentation techniques to produce creative and unique sour beers.
Sour Beer Production Methods
Brewers use two main methods to make beer sour – kettle souring and mixed fermentation.
Kettle Souring
The kettle souring technique involves adding lactic acid bacteria like Lactobacillus to the wort in the brew kettle before fermentation. During a sour mash, the bacteria rapidly produce lactic acid, lowering the pH and souring the wort. This sour wort is then boiled to kill the bacteria and fermented with conventional brewer’s yeast.
Kettle souring is faster than mixed fermentation. It takes about 24-48 hours to sour the wort. This method allows brewers to control the souring process. They can decide when the wort is sour enough before boiling and fermenting it. Kettle souring is commonly used to produce German-style sour beers like gose and Berliner weisse.
Mixed Fermentation
A more traditional technique is mixed fermentation with wild yeast and bacteria. The most famous example is Belgian lambic, which is spontaneously fermented by airborne yeast and bacteria in open vats.
For most modern mixed fermentation beers, brewers inoculate the wort with cultures of wild yeasts like Brettanomyces and lactic acid bacteria. Common bacteria used include Lactobacillus, Pediococcus, and Brettanomyces. The beer ferments and sours over a period of months or years in barrels or foeders. Cultures can also be “re-pitched” between batches to maintain the house flavor profile.
Compared to kettle souring, this wild fermentation method usually results in a more complex sourness. However, it requires significantly more time for aging. Flanders red ale and many American wild ales use mixed fermentation techniques.
Does Belgian Lambic Contain Wheat?
Yes, Belgian lambic beers traditionally contain 30-40% unmalted wheat in the grain bill along with 60-70% malted barley. The wheat content gives lambics their characteristic hazy appearance and adds to the tart flavor.
The wheat is not malted or roasted. Raw wheat grains are added directly to the mash. Unmalted wheat provides fermentable sugars for the wild yeasts and bacteria, but little color or flavor compounds.
Using a high percentage of wheat is a key part of the lambic style. The wheat becomes highly digestible during mashing, allowing for thorough fermentation by the wild microbes. The wheat also provides nutrients for the yeasts and bacteria during aging.
Reasons for Using Wheat in Lambic
- Adds haze and cloudiness
- Provides fermentable sugars for wild yeasts
- Contributes to tart flavor
- Serves as a nutrient source for microbes
- Traditional ingredient in lambic recipes
While lambic brewers could make beer without wheat, the wheat is considered essential for producing the classic lambic flavor profile.
Does Gueuze Contain Wheat?
Yes, gueuze beers also contain unmalted wheat because gueuze is a blend of young and old lambics. Gueuze undergoes the same spontaneous wild fermentation and wheat-heavy grain bill as traditional lambic.
Producing gueuze involves blending 1, 2, and 3 year old lambic beers. The older lambics contribute funky and acidic flavors, while the younger lambic provides natural carbonation. This blend of ages results in the distinctive balanced flavor of gueuze.
But since lambics all contain 30-40% wheat, a gueuze will also inherit that high wheat content from the lambics used in the blend.
Does Berliner Weisse Contain Wheat?
Yes, Berliner weisse is another classic wheat-based sour beer style. 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 color and provides proteins for a frothy head. It also contributes to Berliner weisse’s characteristic tart and acidic palate.
Wheat malt is mashed very lightly to preserve enzymes for the kettle souring process. During boiling, Lactobacillus bacteria are added to rapidly sour the wort before fermentation with ale yeast. So wheat is a necessary ingredient to produce the soured wort.
Reasons for Using Wheat in Berliner Weisse
- Provides hazy, straw color
- Contributes to thick, frothy head
- Adds tart and acidic flavors
- Has enzymes needed for kettle souring process
- Traditional ingredient in Berliner weisse recipes
Do Flanders Red Ales Contain Wheat?
No, traditional Flanders red ales do not contain wheat, they are brewed entirely with barley malt. The grist is made up of a blend of pale, Vienna, caramel, and acidulated malts.
This malt bill gives Flanders reds their distinctive reddish-brown color and provides plenty of fermentable sugars for the mixed fermentation with lactic acid bacteria and wild yeasts. The use of acidulated malt directly contributes to the beer’s sourness.
Although they do not contain wheat, Flanders red ales still develop intense sour flavors through the long mixed fermentation and aging process. Extended barrel aging introduces further acidity from the wood as well as vanilla and oaky flavors.
Do Goses Contain Wheat?
Maybe. Traditional gose beers brewed in Germany do contain wheat, typically around 50% of the grain bill. The wheat provides enzymes for mashing and gives gose its hazy appearance.
However, contemporary American gose beers are not required to contain wheat. Some brewers make goses with 100% barley malt instead. Others use small amounts of raw or flaked wheat.
No matter the recipe, all gose beers will develop a sour character from kettle souring. But only German-style goses use wheat as an essential ingredient.
Reasons for Using Wheat in Gose
- Adds hazy appearance
- Provides enzymes for mashing
- Increases tartness
- Traditional ingredient in German gose recipes
Do American Wild Ales Contain Wheat?
Sometimes. Since American wild ales encompass many different sour beer styles, their grain bills vary widely. Some may contain wheat while others use 100% barley malt.
For example, a brewer making a wheat-free wild ale may use pilsner malt, Munich malt, rye, oats, spelt, or other specialty grains. Another brewer could choose to include raw or malted wheat for protein and haze.
There are no set rules dictating that American wild ales must or must not include wheat. The choice comes down to each brewer’s preferred recipe design and the characteristics they want to achieve.
Other Wheat-Free Sour Beer Styles
In addition to Flanders red ale, here are some other common sour beer styles that traditionally do not contain wheat:
- Lambic-style beers brewed outside Belgium
- Oud bruin
- American sour ales
- Berlin sour
- Straight sour beer
While they may not contain wheat, these beers all rely on bacteria, wild yeast, extended aging, or other techniques to develop their signature sour flavors.
Using Wheat in Sour Beers
For brewers making sour beers, wheat can be a useful ingredient. Here are some of the benefits wheat can provide:
- Haze – Wheat proteins contribute to a cloudy, hazy appearance
- Head retention – Wheat encourages a thick, frothy head
- Tartness – Wheat enhances acidity and sour flavors
- Fermentability – Wheat provides sugars for yeast and bacteria to ferment
- Nutrients – Wheat supplies nutrition for microbe growth during aging
- Tradition – Required for historical styles like lambic and Berliner weisse
Of course, wheat is not essential to make a sour beer. But in many cases, wheat can help brewers achieve the appearance, flavor, and fermentation properties they desire.
Fermentation of Wheat and Barley
The choice of wheat versus barley can impact how the beer ferments and ages due to differences between the two grains:
Wheat
- Provides fewer fermentable sugars – around 75-85%
- Less nutrition for yeast growth than barley
- Protein content contributes to haze
- Imparts tart, dry, crisp flavors
Barley
- Up to 95% of sugars are fermentable
- Significant source of nitrogen for healthy fermentation
- Adds malty, bready flavors
- Higher enzyme content aids in mashing and fermentation
With their differing properties, wheat and barley each bring something unique to the beer. Blending the two grains can allow brewers to strike the perfect balance for their desired sour beer recipe.
Using Adjuncts in Sour Beers
In addition to wheat and barley, brewers can add other cereal grains and starchy adjuncts to sour beer recipes. Some examples include:
- Oats – Contribute creamy mouthfeel and proteins
- Rye – Add spicy flavor and increase head retention
- Corn – Lighten body and boost alcohol content
- Rice – Increase attenuation and dry out finish
- Spelt – Provide proteins for haze and head
These adjuncts can complement the barley malt base and influence the final character of the sour beer. The wild yeasts and bacteria will happily ferment additional carbohydrates from sources other than barley.
Conclusion
Whether sour beers contain wheat all comes down to brewer preference and style tradition. Belgium’s iconic lambic and gueuze beers famously rely on unmalted wheat. On the other hand, Flanders red ales strictly use barley malt. Contemporary American sours may go either way depending on what the brewer is aiming for.
While not mandatory, wheat can certainly lend desirable qualities to sour beers like haze, enhanced acidity, and nutrients for fermentation. Brewers must judge for themselves whether wheat or barley better suits their particular sour beer goals and recipes.
The next time you sample a sour beer, consider if you detect any wheat influences in its appearance and flavor. Checking the brewer’s grain bill may reveal why your favorite sour styles include or exclude wheat when formulating their beers.
