Key factors

1. Maturity: more acid producers (LAB) means more sour
2. Temperature: higher temperature means more sour
3. Type of flour: more whole grain or rye means more sour

Mother Culture

The balance between yeast and lactobacilli (LAB) influences the sourness. More LAB means more acid producers, so a more sour bread.

When feeding the motherdough, influence the balance with:

• Less sour: 22C, white flour, 1:5 ratio of motherdough vs flour, use at peak maturity
• More sour: 29C, <20% rye flour, 1:2 ratio of motherdough vs flour, use after peak maturity

Maturity

Maturity is about when to use the mother culture for the dough. A dough should be active when used for baking. Use it at it's peak rise for less sourness, or let it shrink again to develop more LAB and increase sourness.

Sources

1. Brod and Taylor Part 1
2. Brod and Taylor Part 2

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