Differences between brewer’s yeast, sourdough, and dough maturation time

Alongside flour, water, and salt, yeast is one of the key ingredients in pizza making. There are several types available, but the ones commonly used in pizza dough are brewer’s yeast, sourdough starter, and chemical yeast. So which one should be used for Neapolitan pizza dough?

According to the Vera Pizza Napoletana guidelines, only brewer’s yeast and liquid sourdough (Li.Co.Li.) are permitted.

Most pizzaioli prefer fresh brewer’s yeast, a selected culture that allows for greater control and consistency in fermentation times, making the leavening process more predictable and manageable.

But what are the differences between these two types of yeast? And how do they affect dough maturation?

Brewer’s yeast (either fresh or dry) consists of Saccharomyces cerevisiae, microorganisms that reproduce by budding and multiply exponentially.

In the official guidelines, the amount of fresh brewer’s yeast ranges from 0.1 to 3 grams per 1.6–1.8 kg of flour. When using dry yeast, a 1:3 ratio should be applied (1 gram of dry yeast equals 3 grams of fresh yeast). These quantities vary depending on fermentation time and temperature.

Liquid sourdough starter, on the other hand, is made from flour and water left to ferment in the presence of natural leavening agents, such as lactic acid bacteria or sugars. These sugars attract microorganisms from the surrounding environment, creating a living culture of yeasts and bacteria which, when added to the dough, drives fermentation.

Maintaining a sourdough starter requires regular “refreshments,” meaning periodic additions of flour and water. This involves both a continuous time commitment and a cost in raw materials. The amount of sourdough starter used should generally be less than 10% of the total flour weight.

Due to its more complex microbiological composition, Li.Co.Li. leads to different maturation times and contributes to the development of a richer profile of aromas and secondary compounds, resulting in a more flavorful final product.

When working at room temperature, and depending on the amount of yeast used, dough made with brewer’s yeast typically matures within 8 to 24 hours. With liquid sourdough starter, a minimum of 24 hours is required. These differences are due to the distinct microbiological activity of each type of yeast.

The guidelines do not recommend using both brewer’s yeast and liquid sourdough starter in the same dough. The Saccharomyces strains in brewer’s yeast tend to dominate over the more diverse microbial communities in sourdough. Since they multiply more rapidly, they would outcompete the other microorganisms, consuming the available nutrients and ultimately becoming solely responsible for the fermentation process.