1. Always use the best fruit for your jams and preserves. This is not the place to use substandard fruit. Fruit should be picked slightly under-ripe on a dry and sunny day, and then prepared according to type – peeled, cored, stoned and so on. Wash the fruit only if necessary. Any cores, pips, etc. can be tied up in muslin and cooked along (removed before sugar is added) with the fruit as they contain extra pectin.
2. Cook the fruit along with the acid and a little water if necessary to stop them drying out and burning on the pan. Cook until the fruit is thoroughly softened – the fruit skins will not soften further once the sugar is added. The pectin will also be drawn out of the fruit at this stage.
3. Add the sugar and heat gently in an uncovered pan until the sugar has fully dissolved. You may wish to add a small knob of butter at this stage (optional) which will help prevent any scum forming on the jam.
4. Once all the sugar is dissolved bring the jam (without stirring) to a rapid boil. Time the cooking from the point the rolling boil has reached – the surface will be covered with a mass of foamy bubbles that do not recede when stirred.
5. Once the bubble have started to recede, and the surface of the jam looks glossy and heavy, and keep testing every couple of minutes until setting point has been reached.
6. As soon as the setting point has been reached remove the jam from the heat. Stir gently (always in the same direction) to reduce the amount of scum on the surface of the jam.
7. If the jam contains bigger chunks of fruit (rhubarb, gooseberry etc.) then let the jam cool for 10 mins and then stir before potting. This will help distribute the fruit evenly throughout the jam. Other jams can be potted immediately.
8. Pour into clean sterilised jars (if you have one then just put them in the dishwasher) while the jam is still hot and seal immediately.
9. Store in a cool, dark, dry place, and the jam should last unopened for up to 2 years.