blackberry jam heaven

Today I went blackberry picking with my mum and brother.
You will need to weigh your  blackberries and the same amount of jam sugar or granulated sugar as the blackberries.

Lets get started. First put enough jam jars in a sink of hot water and a bit of soap to get the labels of.  you will need to put your blackberries in a pan with the juice of half a lemon.
The lemon is important otherwise the jam will not set.
Put on a high heat until it boils don't forget to stir it .

Then turn it down and let it simmer for 15 minutes then add the sugar stir it until it dissolves turn it up bring it to the boil. Boil without stirring until it reaches 105 degrees [setting point]. If you don't have a sugar thermometer put a plate in the freezer, then put a drop of jam on it, let it set, then put your finger on the jam and if it crinkles its ready. If not, it's not. Now to sterilise the jars and lids put the jars and lids in an oven on 100 degrees for about 1O minutes take them out and put the hot jam in the hot jars and then you are done.