Note, everyone who makes marmalade will have their own trusted method, and preferred flavour. This one works for me, and is thick, tangy and spicy.
It's probably not as frugal a jam as many others because traditionally it is made from Seville oranges, which are not the sort of fruit that you are likely to have a surplus of. However it is as much fun to do as to eat.
Step 1: Choosing the fruit
You can also add other types of oranges. This version used seven Seville oranges, three lemons and two grapefruit.
Step 2: Washing jars
Wash them, remove the labels (this is easier for some jars than others) and dry them.
Step 3: Peeling the fruit
Here the skins has been scored, so that the fruit is not broken underneath, and a spoon used to ease the skin off. This can be used to scrape excess pith off the peel too.
Step 4: Chopping the peel
Step 5: Separating the juice from the pulp
This is quite therapeutic. If you chop the fruit in half (across the equator so to speak), it stops segments exploding when you throttle them. Do not throw away the pulp, you will need to boil this up to extract the pectin.
Step 6: Boiling the juice, peel and pulp
To prevent the pulp getting in, you need to contain it in a mesh bag. Here a mesh cloth is used, doubled up, and secured with a plastic cable tie. You can get mesh bags in brewing and cooking shops.
Once contained, add 500ml (or just under a pint) of water, and bring to the boil. The whole mixture is then boiled for between 45 minutes to an hour, when the peel will be soft and transluscent. From time to time, squeeze the pulp carefully in the bag (with a wooden spoon) to release the pectin into the mix.
Step 7: Sterilising the jars in the oven
Step 8: Adding the sugar
Once you have squeezed out the sticky juice, you have finished with the pulp and it is not used any more. This leaves you with a strong flavoured thick juice full of pectin and peel.
At this stage add 1Kg of plain white sugar. If you want the best orange taste, do not use unrefined cane, demerara or brown sugar as these have too strong a flavour and can overpower the orange. Of course if you like it more caramelly, you could add tastier sugars, but I prefer it orangey.
You now boil the mixture. Make sure all sugar is dissolved before bringing to a hard boil. Ten minutes should be enough, but this can take longer to reach the point at which it sets. The longer you boil the thicker and darker it will get.
Step 9: Testing if the marmalade is ready to set
Repeat the test every 10 minutes or so, until the marmalade is as thick as you like it. Note it will get darker as it is reduced too.
Step 10: Pouring the hot marmalade into the jars
This can get messy, and you may have to wipe down th jars. Using a thin spoon can be done, or a very wide holed funnel, but this is not essential.
Put the lids on while the marmalade is still hot, and this will create a partial vacuum as it cools. The marmalade will be sterile, and should keep for a very long time.