The science of sourdough can be key to improving the skills of the artisanal baker.

Here I will add papers of interest.


1. Redox Potential

Firstly, the concept of redox potential, a parameter of fermentations not given much attention in the context of sourdough. A stiff, high inoculation, short time cycled starter like LM is likely to be more oxidative than a regular 100% hydration starter.

Redox reactions are a normal function of living microbes but we can observe redox in a macroscopic view which can be quantified by measuring the ORP in millivolts.

From this viewpoint, reduction and oxidation potential is important as this particular parameter can determine how doughs will perform rheologically and provide insights into fermentation status.

Fermentation and Redox Potential | IntechOpen

ORP measurements as a monitoring tool in sourdough fermentations | Baking + Biscuit [PDF]

2. Hydration

Maintaining a starter culture with greater water content or higher hydration increases overall cell numbers of yeasts and LAB. Yeast benefiting more so. Stiff starters do not “slow” LAB or give yeast an advantage contrary to what you may have read. It is true that yeasts can handle lower degrees of water activity but in real terms this concept doesn’t apply since even very stiff starters have water activity values high enough to not put LAB at a disadvantage. The addition of solutes (salt and sugar etc.) will be needed to significantly reduce water activity.

The following papers independently demonstrate the above:

Liquid and firm sourdough fermentation: microbial robustness and
interactions during consecutive backsloppings

Diversity of the lactic acid bacterium and yeast microbiota in the switch from firm- to liquid-sourdough fermentation