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 ↓
Barley-sugar
Ingredients
Directions
Make the syrup
Combine sugar and spring water in a pot.
Add egg white to clarify the mixture.
Boil until it begins to whiten and thickens.
Stir in lemon juice and boil quickly until ready.
Shape and store
Pour onto a lightly oiled marble slab or shallow dish.
When edges harden, shape into sticks, lozenges, or balls.
If needed, reheat gently in a water bath to liquefy.
Store in dry canisters to prevent moisture.
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.
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Sugar + lemontop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
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Egg + lemontop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
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Sugar + eggtop 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
- Sugar
- Forms the body of the candy as it cools into a hard, glassy sugar mass.
- Egg white
- Helps clarify the syrup, collecting impurities so the candy is clear.
- Lemon juice
- Adds acidity that brightens flavour and helps limit sugar crystallisation.
The step that matters
Boil until it begins to whiten and thickens. Sugar must reach the right concentration to set hard when cooled. Under-boiled syrup stays sticky, while overheating can scorch the sugar and give a bitter taste.
Swap the lemon
The recipe marks lemon as optional. How well each one fits the dish's main ingredients (sugar, egg):
- Vanillafits better
- Raisinfits about as well
- Lemonthe original
- Datesfits less well
Fit is the average pairing score against sugar, egg. 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.
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