Blackberry jelly-no pectin

Well, it's that time(in Tennessee). To make jelly without adding commercial pectin, just pick 1/4 of your blackberries under-ripe, that is, with some red on them. Crush one layer at a time just like you normally would. Don't add any water. Bring to a boil then simmer 10 min. Strain out the juice. It doesn't matter how many or how few, this works for 1 cup to one gallon!
Now you have your juice made, measure 2 pints juice and 2 pints sugar in a 4-quart pot. Bring to a boil for 2 minutes. Pour in sterilized jars, add lids, turn upside down for 1 minute then return upright and let cool. Set will be a little looser than store-bought. It will firm up during storage.