How to... Sterilise Jars

Jars must always be sterilised before jams are put in them for storage, or bacteria will multiply. Always use sterilised containers with the correct lid or seal. The jars can be sterilised in an oven or in boiling water.

To sterilise jars in the oven, preheat the oven to 160°C (315°F/Gas 2–3). Place clean, dry jars and lids on a tray and heat in the oven for 10 minutes. Cool slightly, then fill with the warm jam or preserve and put the lid on. As the fruit cools, it will form a vacuum, which will help preserve them.