Sterilising Jars
My preferred method of sterilising jars is by washing thoroughly in hot soapy water with a drop of optional Milton steriliser added to the jar.
I add a little water to the washing up liquid and the steriliser and close the lid. Shaking the jar and emptying the soapy suds and rising well.
If you have used Milton steriliser don't spray your clothes as it will bleach them.
Then place the jars onto a baking sheet and turn the oven onto120C degrees or gas mark for 5 minutes. I tend to leave them in oven until I am ready to bottle the jam.
Even though the fruit is weighed out the water content of the individual fruit may differ, which will yield a different amount of jam. I tend to wash and sterilise more jars than I need. That way if the mixture makes more jam you have the jars ready, if it makes less, you can cool and keep the jars for your next jamming session.