Tangelo Jam - cooking recipe

Ingredients

3 1/3 lb tangelos (around 8-9), zested then chopped
1 tbsp tartaric acid (cream of tartar)
2 None lemons, halved
7 cups sugar

Preparation

Place tangelos in a food processor and finely chop. Transfer to a saucepan along with zest, tartaric acid, lemon halves and 12 cups water. Cook for 2 hours.
Add sugar and continue to cook for 40-50 mins, or until a drop of jam gels when placed on a chilled saucer.