Boil five half-pint jars to sterilize them. When they're ready keep your pot of hot water because you'll need it later.
Combine sugar and pectin in a small bowl. Make sure you have Pomona's Universal Pectin — this low-sugar recipe won't work with other kinds.
Whisk together and set aside.
Nice and small like this.
You should have about two cups of kiwi.
Juice a lemon. You need one tablespoon of juice.
You should end up with about 1.5 cups of strawberry purée.
Calcium water! Make it according to the directions on the pectin box and store the leftover water in your fridge. You need two teaspoons of it this time.
Put the fruit, lemon juice, calcium water, and ginger in a pot and turn the heat up to high.
Let it get to a boil, then add the sugar and pectin mixture and the butter. Stir to combine.
Let it return to a full boil and boil it for a minute. STIR CONSTANTLY.
Skim the foamy bits off with a cold metal spoon.
Jar it and seal them up tight.
Back in the pot of water they go. Boil these for ten minutes, then take them out and let them cool and you're done!