Sterilising jars ready for filling with preserve.

Whenever you’re making jams, jellies, marmalades, chutneys, whatever, one of the secrets of success is to always make sure your preserves go into very clean, sterilized jars. This is to prevent any growth of mould and will also help with the shelf life of your preserves.

Sterilizing Jars in the Microwave

It’s actually quite straightforward to do, and it is something you should never omit when making preserves. So, if you’re just using plain, simple jam jars, the quickest, easiest method of sterilizing is to rinse them in cold water, leave them damp, pop them into the microwave for about 30-45 seconds, perfect.

Don’t Put Metal in Microwave

However, if like me you like to make your preserves in bulk, you’ll notice they have metal fixings on them, not a very good idea to put them in the microwave. So the best way of sterilizing these jars is to use the tried and tested method, in the oven. Before you do that, check that you have removed any rubber seals from these jars before they go in the oven.

Place Jars in the Oven

All you need after that is a pair of oven gloves and a thick wad of newspaper. Firstly, heat the oven to about 130 degrees Celsius. Don’t be tempted to turn the oven up any higher, this is a sufficient temperature to sterilize the jars. Then on the lower shelf of the oven, lay the newspaper. The newspaper acts as an insulator between the jar and the metal shelf, which prevents cracking during sterilising. Place the jars on the newspaper, making sure the jars are not touching each other. They will expand during heating, keeping them separate prevents them from cracking. Close the oven door and leave the jars for about 30 minutes, until the jars are lovely and hot.

Let Sterilized Jars Cool

When you are ready to use your hot, sterilized jars, use your oven gloves to remove them from the oven one at a time, putting them onto a heat-proof surface. Fill immediately with hot preserve, seal with a rubber ring. Just one final note, never heat the jar for sterilising until you’re actually ready to use them and only ever put hot preserves into hot jars, this is to prevent them shattering and causing accidents.