During the development of sourdough, a natural phenomenon is used: fermentation. And in the course of this fermentation, two major acids develop, helping both to develop flavors and improve the final texture of the bread made with this sourdough: lactic and acetic acids. But what are their roles in practice, and why are these acids so important for the baker who wants to master sourdough? In this post, BRO takes a closer look at lactic acid and acetic acid in sourdough.

Lactic acid in sourdough: role and particularities

Lactic acids in sourdough are first and foremost produced by bacteria, the best known of which are Lactobacillus, Streptococcus and Bifdobacterium. The latter play a central role in natural sourdough fermentation. Indeed, it is these same bacterias that are responsible for converting sugars into lactic acid.

And the reason they’re so important is that lactic acid’s role in sourdough is not insignificant! Once the sugar has been converted into lactic acid, it helps acidify the dough used to make bread and other specialties. This acidification process transforms the carbohydrates and proteins naturally contained in the dough, improving their digestibility.

In addition, the lactic acid in the sourdough develops its flavors through its slight acidity, improving the overall texture of the sourdough, both in terms of elasticity and structure. When sourdough bread is baked, lactic acid is what gives the specialty an airy crumb and a truly crisp crust.

What you need to know about acetic acid in sourdough

In addition to lactic acid, another less important acid also plays a role in sourdough’s unique profile: acetic acid. Also formed from lactic acid bacteria, acetic acid helps to lower the pH of the dough and thus plays a role in the transformation of carbohydrates and proteins. But as an added bonus, acetic acid stabilizes the pH and prevents overfermentation. Like lactic acid, it helps to develop the sourdough’s flavours by adding acidity, but also a slightly piquant taste.

But acetic acid’s real advantage lies in the dough. Acetic acid contributes to the production of carbon dioxide, which is useful for giving a more airy texture to the final bread as the dough rises.

So, if you were wondering about the roles of lactic and acetic acids in sourdough, you can rest assured that they are partly responsible for sourdough’s unique properties and help develop its characteristic flavor.