Sugar syrup and its stages

Why

Sugar dissolved in water raises the boiling point, and the more water boils off, the more concentrated the syrup becomes and the higher the temperature climbs; the temperature therefore tells you how much water is left and how the syrup will set once cool. For a long time it stays just above 100 °C, but towards the end, as the water runs out, it rises faster and faster and one stage follows the next in moments. As a guide: thread about 110–112 °C, soft ball 112–116 °C, firm ball 118–120 °C, hard ball 121–130 °C, soft crack 132–143 °C and hard crack 146–154 °C; above about 160 °C the sugar caramelises (see the Caramel card). Thin syrups for soaking pastries such as baklava or revani are only boiled briefly; the traditional rule is to pour cooled syrup over hot pastry, or hot syrup over cooled pastry, because if both are hot, crisp pastry easily turns soggy. Syrup is 10 to 50 °C hotter than boiling water, sticks to the skin and burns deeper.

How to do it

• Check the thermometer in boiling water; if it doesn't show 100 °C, shift the target by the same difference, which also covers altitude (at 600 m water boils at about 98 °C).
• First dissolve the sugar completely while stirring, and only then let the syrup boil without stirring; wash crystals off the sides of the pan with a wet brush (see the Caramel card).
• Clip the thermometer so it does not touch the bottom of the pan, and don't walk away towards the end: the last degrees climb fastest.
• Without a thermometer, drop a little syrup from a spoon into a glass of cold water and feel the cooled drop: thread, soft or hard ball, or brittle crack.
• For baklava and similar crisp pastries, pour cooled syrup over the hot pastry, or hot syrup over the cooled pastry; gulab jamun, by contrast, are traditionally soaked hot in warm syrup.
• Use a deep, heavy-based pan, keep children away from the stove, and never taste or touch hot syrup.

If it goes wrong

Overcooked syrup can be saved: take it off the heat and, keeping your distance, add a little hot water, as it boils up and spits; dissolve it over gentle heat and boil it again to the right temperature. Dissolve crystallised syrup with a little water and boil it again without stirring. Boil runny syrup a few degrees higher. Cool a burn at once under cool, not icy, running water for at least 20 minutes and don't peel set sugar off the skin; see a doctor for a burn larger than a palm, with white or charred skin, on the face or hands, or in a child.