When making jam or other preserves it is important to have clean jars and bottles for keeping the preserves in. This prevents the quick deterioration of quality that would otherwise happen. An easy way to do this is to clean the jars thoroughly, then place them in a cold oven. Turn the heat on to 180oC and leave the jars in the oven for 20 minutes after this temperature has been reached. The glasses are now sterilised.
If you use metal lids you should follow the same process for the lids as you did for the jars, they can all go in the oven together.
Remove jars from the oven as and when you need them, using a heat proof cloth so as not to burn your fingers. Place them on a heatproof mat that can be washed, as you will probably spill some jam here and there.
Add your jam to the jar while they are both warm, and leave for a few minutes before adding the lid.
Some important points to remember are:
- Always sterilise more jars than you think you need, there is nothing worse than not having enough jars and having to repeat the process.
- Never add cold food to hot jars or hot food to cold jars, the glass will shatter and the food will be ruined.