Make strawberry jam using just sun light
Solar cookers are not just for making the meal of the day: you can use your solar cooker to conserve food by making jam, chutneys and other preserved foods. If you grow your own soft fruits, try this recipe tested on SolSource solar cooker.
2lb granulated sugar or caster sugar
½ lemon, juice only
A little butter
The day before
The day before you wish to make the strawberry jam, hull and halve the strawberries. Check for soft spots (which must be removed) and discard any berries with bruises or that are overripe.
Place the strawberries into a large bowl with 1 lb of the sugar. Turn carefully to mix and coat well, then cover with cling film and place somewhere cool overnight.
Making the strawberry jam
Sterilise the jam jars – first wash the jars in soapy water and rinse well. Placed them in a deep saucepan, cover with water and bring to boil on your SolSource solar cooker – then boil for 10 minutes. Cover until ready to use.
Pour the strawberries, their juice and any residual sugary juices into a very large pan or preserving pan, remembering that the mixture will rise as it boils, and add the remaining 1 lb sugar and the lemon juice. You may prefer to do this in two batches.
Put pan onto SolSource solar cooker and stir over until the sugar has completely dissolved.
Checking the setting point
Bring the strawberries up to the boil (usually about 10-15 minutes with strong sun light) then boil hard until the jam reaches setting point. Check the setting point every ten minutes, although it may take up to an hour to reach setting point – depending on the water content and acidity of your fruits. Also re-adjust your SolSource Solar Cooker to follow the direction of the sun.
To test the setting point, remove the pan from the heat. Place a drop of jam onto a cold plate. After a few seconds push the jam with your finger. If the jam surface wrinkles then it has reached setting point and is ready. If it slides about as a liquid, then it hasn’t reached setting point and should be returned to the heat and boiled for a few more minutes before testing again.
When setting point has been reached, remove the pan from your SolSource solar cooker. Stir in the butter. Skim off any scum on the surface of the jam with a large spoon. Let the jam cool and thicken in the pan for 10-15 minutes, so that the strawberries don’t all sink to the bottom in the jam jars.
While the jam cools, put the deep saucepan containing your sterialized jam jars on your SolSource solar cooker and bring it back to the boil.
Filling the jam jars
Carefully remove the sterilised jars from the saucepan with tongs – try to avoid touching the insides of the jars which might introduce unwelcome bacteria.
Stir the jam, then ladle it into the sterilised jars. Use a jam funnel, if you have one, to avoid spilling too much jam. Optionally, cover the top surface of the jam in each jar with waxed paper discs that have been cut to size – they should cover the entire surface of the jam. Press the wax disc down to create a complete seal.
Cover with a lid while still hot, label and store in a cool, dark cupboard for up to a year.
Water bath canning
If you want to store your jam for up to two years, you can follow standard water bath canning process with your SolSource solar cooker to enhance the shelf life of your jam.
Of course, you can conserve other fruits too – raspberries, blackberries, red currants and black currants. For fruits with low water content, you can mix the fruits and sugar, and cook them straight away without the need to soak them overnight. Also, the cooking time will be shorter due to higher concentration of pectin and acidity. You can also use your SolSource solar cooker to make chutney, relish and other condiments to go with stews and cheeses.