Name: Ferment with Compressed Yeast
Ingredients: 2½ pounds potatoes; 1 pound flour; 2 ounces sugar; 1½ ounces compressed yeast; water as needed

Why it works: Flour and sugar are a kitchen classic. They rank in the top 15% of all ingredient pairs, and cooks put them together in 92,116 recipes. Both carry phenylacetaldehyde, which smells hawthorne, honey. The science ↓

Ferment with Compressed Yeast

10 quarts

Ingredients

Directions

Prepare the potato mash

Boil the potatoes until done.
Combine a portion of the boiling water with the potatoes in a large tub.
Add the flour.
Scald the mixture well. Mash it to a fine, smooth paste.
Add more water to thin the mixture.
Cool it to about 75°F (24°C) to make 10 quarts.
Strain the mixture.

Ferment

Add the sugar and yeast.
Cover the tub tightly.
Let it sit undisturbed for 10 to 12 hours.
For a quicker fermentation, raise the temperature to 95°F (35°C).
Use more yeast to be ready in 5 to 6 hours.

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

The flavor team

The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.

Flour + sugartop 15% of all pairs

Smell alikemoderate

Cooked together92,116 recipes

Shared aroma: phenylacetaldehyde (hawthorne, honey).
Potato + flourtop 15% of all pairs

Smell alikemoderate

Cooked together5,355 recipes

Shared aroma: isobutyraldehyde (malty, green).
Potato + sugartop 30% of all pairs

Smell alikelow

Cooked together3,032 recipes

Shared aroma: beta-damascenone (apple, rose).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Potatoes: Provide starch and body that give the bread its moist, soft crumb.
Flour: Supplies gluten-forming protein and starch to build structure in the dough.
Sugar: Feeds the yeast during fermentation and adds mild sweetness.
Compressed yeast: Produces carbon dioxide during fermentation, causing the dough to rise.

The step that matters

Cool the mixture to about 75°F (24°C) before adding the yeast. Yeast works poorly in very hot liquid and can be killed by it, while a mixture that is too cool ferments slowly. Bringing it to a moderate temperature lets the yeast grow and produce gas steadily.