Using beer instead of yeast to make bread is an intriguing idea, but there are several important factors to consider before substituting beer for yeast in bread recipes. In the opening paragraphs, we’ll provide a quick overview of the requirements for yeast in bread and whether beer can meet those needs. We’ll also touch on the potential impacts to taste, texture, and rise that brewer’s yeast from beer may have compared to baker’s yeast more commonly used in bread.
Yeast’s Role in Bread
Yeast is a critical ingredient in most bread recipes. Yeast feeds on the sugars in bread dough, producing carbon dioxide gas and alcohol as byproducts through the process of fermentation. The carbon dioxide gas gets trapped in the dough, causing it to inflate or rise. The stretchy gluten network in the dough then sets around the gas bubbles, giving bread its airy, spongy texture.
Baker’s yeast, or Saccharomyces cerevisiae, is the species of yeast most commonly used for bread. Baker’s yeast is specially cultivated to optimize the fermentation process and aroma for baked goods. It’s bred to produce more CO2 gas and less alcohol compared to brewer’s yeast. Brewer’s yeast, or Saccharomyces carlsbergensis, is optimized for beer production where more alcohol and less gas is desirable.
While both baker’s and brewer’s yeast are strains of Saccharomyces cerevisiae, they have been selectively bred over generations for different purposes. Baker’s yeast generally has more vigorous fermentation with optimal temperatures between 80-110°F. It can produce up to twice as much CO2 as brewer’s yeast. Brewer’s yeast grows best at cooler temperatures between 60-75°F and has a less vigorous fermentation.
The different fermentation rates and byproducts will impact the texture, rise, and flavor of bread made with brewer’s yeast. Brewer’s yeast may produce more residual sugars and alcohol, affecting the taste. The reduced CO2 production can result in denser bread with a finer, tighter crumb structure.
Using Beer as a Yeast Source
While brewer’s and baker’s yeast have key differences, it is possible to use the yeast leftover in the sediment of beer as a leavening agent for bread. However, there are some important caveats:
Low Yeast Viability
By the time fermentation is complete in beer, a large percentage of the yeast cells (up to 90%) are no longer viable. There are far fewer active yeast cells compared to the amount of yeast called for in typical bread recipes. Significantly more beer sediment would need to be used compared to baker’s yeast to get enough fermentation activity.
Other Impacts on Taste
The flavonoids, acids, and other compounds from beer will also impact the flavor of bread made with the yeast sediment. This could add interesting complexity but may not always be desirable depending on the style of beer and bread. The alcohol leftover in the beer can also inhibit yeast fermentation.
Like beer sediment, sourdough starter also contains a mix of yeast and bacteria. In contrast to beer sediment though, sourdough starter contains a robust and active culture optimized for leavening bread. The lactic acid bacteria in sourdough also produce additional acids that contribute to sourdough’s unique flavor.
When Beer Yeast Could Work
While less than ideal compared to baker’s yeast, beer yeast sediment could still potentially leaven bread in a pinch if baker’s yeast is unavailable. A greater quantity of sediment would be needed compared to the amount of baker’s yeast called for in a recipe. Expect the rise, texture, and flavor to be impacted.
Supplementing a small amount of baker’s yeast in addition to the beer sediment could help create a more active fermentation. Allowing for a longer first proof to generate more CO2 may also compensate for the reduced yeast activity.
Bottoms from bottles of active beers like IPAs or stouts could provide more viable yeast than filtered or pasteurized beer. Cloudy hefeweizens and Belgian witbiers with live yeast could also work. Dark beer sediment may impact the bread’s color. Lean towards lighter beers for aesthetics.
The yeast in beer sediment may work better in quick breads like soda bread, banana bread, or beer bread where the goal is just a bit of rise and light texture rather than large voids. The acidic pH of beer sediment can react with baking soda to give additional lift to quick breads.
While it’s scientifically possible for the yeast in beer sediment to leaven bread, baker’s yeast is better optimized for optimal rise, texture, and flavor. The lower fermentation activity and other flavor compounds from beer are likely to impact the finished bread. However, beer yeast could work in a pinch, especially if supplemented with a small amount of baker’s yeast. Quick bread recipes are more forgiving, but expect results to vary based on the type and viability of beer used. For best results, stick with regular baker’s yeast and save the beer for drinking!