This marmalade combines a spirit of your choice with grapefruits, lemons and oranges. For best flavour select a good quality spirit.
Juice the fruit and pour the juice into a large, lidded pan with a capacity of 6-8 litres/10-14 pints. Add the water.
Scrape out the inner membranes and pips from the fruit with a small sharp knife. Put the membranes into a food processor or mini-chopper and chop finely. Put the chopped membranes, and any pips, into a muslin bag or a piece of muslin tied with string. Add to the pan.
Shred the peel to your preferred thickness and add it to the pan. Set aside to allow the peel to soak for a few hours or, if possible, overnight.
Bring the lidded pan to boil, reduce the heat and simmer very gently for two hours. The peel should be very tender.
Meanwhile, preheat the oven to 140C/275F/Gas 1. Pour the sugar into a baking dish and warm in the oven for a few minutes.
Remove the muslin bag from the pan and squeeze the liquid from the bag into a bowl. Pass through a sieve and add to the pan.
Weigh the contents of the pan - it should be no more than 1.4kg/3lb 1oz. If you have more than this, return the contents to the pan and simmer to reduce the liquid until the correct weight is achieved.
Add the warmed sugar to the pan and stir until dissolved. Gradually bring the pan to a rolling boil. After seven minutes, test the setting point by scooping out a large spoonful of the marmalade. Allow the mixture to cool a little, then slowly pour it back into the pan. If it is at the setting point, the drops will run together to form a hanging flake (this is known as the flake test). It can take up to 30 minutes to reach setting point, so keep testing.
Leave the marmalade to cool for 5-10 minutes (a skin should form on the surface). Remove any scum from the surface and add the spirit of your choice to the pan. Gently stir the marmalade to evenly distribute the peel and the alcohol.
Pour the marmalade into sterilised jars and seal. Leave the jars upright and undisturbed to set.