Dissolving Sugar For Jam

Our answer

Nigella's Chilli Jam (from NIGELLA CHRISTMAS) is made with a base of cider vinegar and jam sugar. Jam sugar contains pectin, which makes the jam set, and also has slightly larger crystals to reduce the amount of scum that may rise to the surface of the jam as it boils. The sugar needs to be completely dissolved before the chillies are added and the mixture is boiled. If it is not completely dissolved then the jam can crystallize when it is cooled and stored.

Unfortunately the larger crystals do take a long time to dissolve completely and this needs to be done on a low heat, so some vinegary fumes will emanate from the pot. If you warm the jam sugar in the oven before you add it to the vinegar then this can sometimes speed up the rate at which the sugar dissolves. To warm the sugar, put it into a heatproof bowl and into an oven preheated to 140C/275F, stirring the sugar once or twice while it warms. The sugar should take about 30 minutes to warm up, though the time will depend on the depth and diameter of the bowl so it is best to keep an eye on the sugar. Once the sugar is warm you can use the oven to sterilize your freshly washed jam jars.