Makes 500ml
400g sugar
500g fresh or frozen raspberries
Juice of one lemon

1 Mix all the ingredients in a pot and chill overnight to draw out the pectin from the raspberries. Pectin is a gelling agent for jams that is found in some fruits.

2 Cook the mixture over low heat for one hour, stirring every 10min to prevent it from sticking to the bottom.

3 While the jam is cooking, wash empty jars and their lids with warm, soapy water. Sterilise by heating in a 110 deg C oven for 10min, until they’re dry.

4 To test if the jam is ready, dip a spatula into it, then run your finger over the spatula. The jam is of the right consistency when the two lines that were parted by your finger don’t merge. 

5 Transfer the jam to a jug, then pour it into the jars, filling each up to the collar.

6 Seal the jars while the jam is still hot. The hot air between the jam and lid creates a vacuum that seals the bottle. The jam can last up to six months at room temperature. Once opened, chill and consume within a month.

This article was originally published in Simply Her January 2014.