Grapefruit Marmalade

Directions

1. 1
   Peel grapefruit and lemon and cut away 1/2 pith from rind. Cut rind into slivers. Chop the fruit and reserve, along with any juice.
2. 2
   In an 8-quart non-reactive heavy pot, simmer rind, chopped fruit, reserved juice, water and sugar uncovered on low heat, 10 minutes.
3. 3
   Pour into a large heatproof glass bowl and let stand, covered, in a cool place overnight.
4. 4
   Return grapefruit mixture to a pot, and heat on medium-high heat until a sugar thermometer registers 220 degrees F, about 20 to 25 minutes.
5. 5
   Remove from heat, skim off the foam and ladle into sterilized half-pint canning jars, leaving 1/4-inch space at the top Wipe rims, seal jars and process in a boiling water bath for 15 minutes.