Why it works: Sugar and lemon are a kitchen classic. They rank in the top 18% of all ingredient pairs, and cooks put them together in 53,532 recipes. Both carry 2-nonenal, which smells fatty, green. The science ↓
Clear Soup
Ingredients
Directions
Clarify the stock
Skim the grease from the soup-jelly in the crock, leaving meat and sediment behind.
Heat the grease in a soup kettle until it boils.
Stir in the beaten egg white.
Remove the scum as it rises.
Add the soaked gelatin.
Add a little boiling water to the sediment and meat in the pot.
Strain off the liquid.
Ensure the meat is clean before adding it back to the soup.
Colour and finish
Prepare colored water by burning sugar.
Add boiling water to the colored water.
Stir until clear.
Add the colored water to the soup.
Simmer for a few minutes without boiling.
Serve with sliced lemon.
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.
Photo for illustrative purposes only · Contact us to use it
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.
-
Sugar + lemontop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
-
Egg + lemontop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
-
Egg + sugartop 21% of all pairsSmell alikemoderateCooked together122,807 recipes
Shared aroma: 2-nonenal (fatty, green).
Sugar and lemon barely smell alike, yet cooks put them together in 53,532 recipes: they work on texture and structure more than aroma.
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Beaten egg white
- Gathers impurities and clouds as it cooks, so they can be removed, clearing the soup.
- Coxe's gelatine
- Adds body and a light jelly-like texture to the soup.
- Colored water (made from burning sugar)
- Adds a brown colour to the soup.
The step that matters
Simmer for a few minutes without boiling. Boiling a clarifying soup breaks up the egg white raft and cloudies the broth, so it should only simmer gently.
Swap the lemon
How well each one fits the dish's main ingredients (egg, sugar):
- Vanillafits better
- Raisinfits about as well
- Lemonthe original
- Datesfits less well
Fit is the average pairing score against egg, sugar. Candidates are from the same food group and used in at least 100 recipes.
“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.
More clear soup recipes
You might also like
The free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.
Prefer an account? Create a free account to save pairings and unlock the full chemistry.

Lemon Sauce236 recipes
Tomato Soup526 recipes
Brown Bread461 recipes
Mutton Broth292 recipes