Name: To Purify Yeast for Bread or Cakes
Ingredients: large quantity of cold water; fresh water; small portion of brown sugar

To Purify Yeast for Bread or Cakes

A method for purifying yeast by soaking it in cold water, draining, and rinsing with fresh water, optionally adding brown sugar.

From an old cookbook · modernised transcription

From a historical cookbook (Internet Archive) · 3 ingredients

To Purify Yeast for Bread or Cakes

Ingredients

large quantity of cold water
fresh water
small portion of brown sugar

Directions

Wash the yeast

Mix the yeast with a large quantity of cold water.
Let the mixture sit overnight in a cool place.
Drain off the water.
Stir the yeast with fresh water.
Let the mixture stand for several hours until the water is clear.
Change the water daily in winter and twice daily in hot weather to preserve the yeast.

Revive before baking

If the yeast ferments less freely, stir in a small portion of brown sugar before making bread.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.

Explore the science

What each ingredient does

Yeast (in the method): Ferments the dough, producing gas that makes it rise.
Brown sugar: Feeds the yeast, giving it fuel to ferment more freely.

“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.