Bread made from 100% rye flour, popular in northern Europe, is typically
leavened with sourdough rather than baker’s yeast, as rye lacks sufficient
gluten to support yeast leavening. Instead, rye bread’s structure relies
on the starch in the flour and other carbohydrates known as pentosans.
However, rye amylase remains active at higher temperatures than wheat
amylase, which can cause the bread’s structure to weaken as the starches
break down during baking. The lowered pH of a sourdough starter
inactivates the amylases when heat alone cannot, allowing the
carbohydrates to gel and set properly in the bread structure."
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Coded by Johanna Häusler