Starting the starter
Baking sourdough bread starts with a so-called starter. This is a mixture of microbes responsible for the fermentation of the bread. In short, the yeasts and bacteria in this starter ensure that the dough rises and that it gets the well-known sourdough taste. The starter is made with water and flour. You then grow the microbes that were already present in this flour, for example by regularly refreshing parts of it. Because you are working with 'wild' microbes, the bread often needs longer to rise, but this means that starters can also differ a lot from each other.
Smelling the microbes
With this knowledge, the researchers went to work. They have made starters with 10 different types of flour. All these starters were treated exactly the same. They then looked at the DNA, the genetic material, that could be found in the starters. The acidity (pH) and odour of the starters were also closely monitored. And guess what? After about 14 days, different types of bacteria were present in the different types of flour. These bacterial species can handle the nutrients just better, which are also slightly varying between each type of flour. Because every bacterial species has their own metabolism, every bacterium also produces different substances that end up in the starter. As a result, a specific bacterial composition in your starter also results in specific odours.
Get to work
This research is not only interesting for microbiologists, home bakers can also get started with it. The researchers described the smell of different starters. For example, the use of rye gives a fruity scent and buckwheat an earthy scent. Because smell is very important for people to taste flavours, they could also taste very different. The best thing, of course, is to test this out yourself and make the sourdough starter that suits you best. It may take some trial and error, but then you can bake many loaves of bread with your ideal starter. Which flour will you try first?
Author: Eline van Bloois