STERILISING BOTTLES

For all preserving you need to have your bottles, jars and other equipment free of bacteria or moulds or anything that could prove harmful if allowed to stay in the jar and affect the food. All jars and lids should be spanking clean AND sterile.

A dishwasher will not only clean the jars and lids, but the heat of the water will sterilise them. If you’re hand washing jars, or using jars that have been stored for a while, you’ll need to sterilise them using boiling water or a hot oven. Many people take the clean jars and place in cold water then bring to the boil. (The risk of jars shattering comes when there is a great change in temperature; hence the cool jars in cool water to start.) The difficult thing is removing the hot jars from the water and keeping them sterile without dropping them, though you can buy special tongs for this purpose.

Clean jars can also be put into a cool oven and heated to 100°C (200°F). You need to be careful when you heat the lids because if you heat them much past 100°C the rubber seals can melt or harden. The simplest sterilising method is the microwave; you can kill bacteria and spores by placing empty, clean and dry jars in the microwave for about 30 seconds per jar. However, this won’t work for metal lids.

There are commercially available chemical sterilisers, often called sanitisers, which kill bugs too, and these are useful for sterilising lids, as well as the tools used for making salami or cheese. They’re often found in the baby section of supermarkets. We try to avoid chemicals, so tend to use a big pot of boiling water to sterilise most utensils, and a mix of dishwasher and boiling water for sterilising jars and their lids. Remember, when you go to fill the jars, the heat of the jar should be about the same as the heat of the ingredient; so hot liquids should go into hot jars, cold liquids into cold (again, to avoid the risk of the glass shattering).