Wash blackberries, and transfer to a large bowl or pot
Crush, and stir in sugar
Let berries and sugar mixture sit for 10-15 minutes to start dissolving the sugar crystals
Meanwhile, combine 3/4 cup of water and packet of Sure Gel in a small sauce pan, and bring to a boil while stirring. Note: it may be lumpy at first, but it will smooth out as it heats
Boil for 1 minute
Remove from heat, and add to blackberry mixture
Stir for 3-4 minutes until sugar is dissolved, or mostly dissolved
Pour into refrigerator or freezer safe containers, and fit with lids
Let rest at room temperature for 1-2 days
Store in refrigerator for up to 3 weeks, or the freezer for up to a year.