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
In a large pot, combine the sugar and spring water.
Add enough egg white to clarify the mixture.
Heat until it begins to whiten and thicken.
Stir in the lemon juice and boil quickly until it reaches the desired consistency.
Optionally, add a few drops of essence of lemon just before removing from heat.
Shape and set
Pour the mixture onto a lightly oiled marble slab or shallow dish.
When it starts to harden at the edges, shape it into sticks, lozenges, or balls.
If it cools too quickly, place the vessel in a pan of water and gently reheat to liquefy.
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
- Highly-refined sugar
- Forms the glassy, hard candy base as it is cooked to a supersaturated syrup.
- Egg white
- Clarifies the syrup, binding impurities so they can be skimmed away for a clear candy.
- Lemon juice
- Adds acidity that helps prevent sugar from crystallising, keeping the candy smooth.
The step that matters
Boil quickly to the desired consistency. Sugar candy sets according to how far the syrup is cooked; too little boiling leaves it sticky, while overcooking makes it brittle or burnt. Watching the stage closely controls the final texture.
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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