Processintermediatedraft
Sugar crystallises
Also searched as: sugar turns grainy, crystallising, fondant, fudge
In short: Dissolved sugar wants to form crystals again. Even a single grain can set off a chain reaction.
Picture it
Like dominoes: when one falls, they all fall. A sugar crystal on the side of the pan is enough as the first domino.
Level 3 · Sugar syrup cooling down≈ 0.1 mm
Simplified model
What happens
Hot syrup holds far more dissolved than it can hold when cold. As it cools, or when stirred, the sugar molecules attach to any crystal present, and the syrup turns grainy. Acid, honey or glucose syrup disrupt crystal formation and keep caramel smooth.
Why it matters
Explains why caramel suddenly turns sandy, and why with fudge you control crystallisation on purpose.
Where you meet it
Rules of thumb
- Do not stir while sugar is boiling. Swirl instead of stirring.
- Wash crystals off the side of the pan with a wet brush.
- A spoonful of glucose syrup or a little lemon juice prevents graininess.
Levers
2
Mechanical work (kneading, whisking, stirring)stirring → crystals
Temperaturecooling → crystallisation
Related entries
Caramel turns grainySources · 1
- Harold McGee: On Food and Cooking (2004), Kapitel Milch, Zucker, Schokolade