Stopping Toffee from Crystalising

Stopping Toffee from Crystalising

15 Oct 2019 - Anneka Manning

Toffee is often used to embellish or complement bakes (think praline, spun toffee and toffee shards). But there is nothing more frustrating than when it crystalises and becomes a horrid grainy mass making it unusable.

The crystalisation of toffee starts when it contains a ‘seed’ which can be either an undissolved sugar crystal (like those that form as the syrup splatters on the side of the pan during boiling) or something foreign in the mixture like a small crumb. As the toffee cools and the molten sugar crystals become solid again, they are attracted to the ‘seed’ forming new lumps of tiny crystals – hence the grainy texture.

This can also happen if the toffee is stirred, or agitated, after it has begun to boil or on cooling (as happened with this pink-tinted toffee). This agitation not only helps in the formation of the ‘seed’ crystals but also encourages the cooling syrup to be attracted to them and hence the development of crystal clusters and a grainy mass.

So how do you stop crystalisation? There are three main rules to follow for smooth, glass-like toffee:

  1. Stir the combined sugar and water over a low or medium heat until the sugar dissolves completely before it comes to the boil.
  2. Once the syrup begins to boil, don’t stir it again while it cooks (although gently tilting the pan from side to side occasionally will be fine) or while it is coolsing.
  3. Use a pastry brush that has been dipped in clean water to brush down the sides of the pan occasionally during cooking. This will dissolve any sugar crystals that have formed from splattered syrup.