The Science of Sourdough

 
 
A common misconception about sourdough bread is that it must taste sour. Yet as David Deblauwe, regional product manager, Bakery Flavors & Yeast, for Puratos Corp., explains “there are as many sourdoughs as there are sourdough makers.” Time, temperature and know-how of the individual baker all contribute to the unique flavor of one sourdough from the next.
 
“I think we are at the tip of the iceberg as to what we know about sourdoughs,” he says. “We currently have 102 sourdoughs in the Puratos Sourdough Library. They are all unique in some way.”
 
Lactic acid bacteria and wild yeasts are present everywhere in the world. To create sourdough, “either you let nature do its work,” as Deblauwe explains, or you add things like yogurt or green coffee beans (which is what a baker in India is doing with success). The method that Deblauwe says will be most consistent involves using pure blends of lactic acid bacteria and yeast.
 
Temperature has a definite influence; warmer temperatures will lead to a milder, more lactic flavor, while colder temperatures will produce a zesty, more acidic flavor.
 
“Time and temperature will start to influence the flavor you will get,” he says. “One of the challenges for bakers is that you will, for sure, have a different sourdough in the winter or summer. That’s where our solutions can play a role in bringing that consistency.”
 
And there is the influence of human hands. The Puratos Center for Bread Flavour is working to analyze the hands of bakers in different countries to determine the influences on flavor of sourdough bread. “Now we will have scientific evidence. We want to make sure we protect the future of sourdough.”
 
The purpose of the Puratos Sourdough Library, a physical library where sourdough samples are stored, is threefold: preserve the biodiversity of sourdough, serve as a backup, and conduct research. The library was launched in 2013 at the Center for Bread Flavour in Belgium. New sourdough cultures are collected each year from around the world, and every year Puratos conducts extensive study on the sourdoughs of a specific region. All this research creates a wealth of knowledge on the science of sourdough. 
 
“We are analyzing 24 sourdoughs every year,” Deblauwe says. “We want to protect the past for future generations. We also don’t know yet how many platforms there are in the world.”
 
Scientists know that certain microorganisms are present in certain regions. There are many variables to study. Puratos, for instance, has discovered two “very similar” sourdoughs that come from areas that are a thousand miles apart. The common variable? They are maintained at the same altitude.
 
In the end, Deblauwe says that the valuable research conducted by Puratos with bakers from around the world will lead consumers to understand and enjoy the many different flavors that are possible when creating sourdough bread. “I think you can really create big differences,” he says. “I don’t want to make the same sourdough every weekend.”