Pink Grapefruit Marmalade

Finish. Measure the sugar into a big bowl and keep to one side. Wash grapefruit plus take out rinds in quarters. Discard 4 of this quarters (the rind of 1 grapefruit). Cut into thin pieces leftover quarters lengthwise, next roughly chop them across into smaller pieces. Move rinds to a big pot and add 2 cups of water and bicarbonate of soda. Bring to the boil over a medium-high flame, cover, lower the heat, and simmer till the rinds are soft and starting to turn translucent, around 15 minutes. Roughly chop grapefruit and remove any seeds while that is happening. Move grapefruit to a food processor and blitz in short bursts till coarsely chopped. Tip in fruit to pot using the rind and return the mixture in order to a simmer. Simmer, covered, till the fruit has softened a bit, around 15 minutes. Measure of the fruit mixture (5 cups), making sure in order to get a good combination of rind, fruit, plus juice. Discard the leftover fruit mixture. Return the set-aside of the fruit mixture to (5 cups) the pot. Mix in the pectin and butter and bring to the boil over a high flame, mixing the whole time. Tip in sugar all at once plus return the mixture to a full rolling boil, mixing the whole time. Boil hard for 1 minute. Take out pot from heat and skim any foam off surface of the marmalade using a cold metal spoon. Ladle marmalade in hot, sterilized jars. Clean rims, apply lids and rings, plus process in a boiling water bath for a period of 10 minutes.