Making Fruit Preserves
Preserving fruit is simply a matter of cooking fruit with sugar and acid until the pectin sets and the water content reduces enough to prevent spoilage. You bring the mixture to a rolling boil, maintain it until it hits the gelling point, and pour it into sterilized jars to seal.
Consistency is your only metric.
The goal is to drive off moisture so the jam sets without turning into rubber or remaining a syrup. Keep a saucer in the freezer to test the thickness as you cook.
- Heavy-bottomed wide pot
- Canning jars with new lids
- Water bath canner or deep stockpot
- Jar lifter tongs
- Saucer
What goes in.
- 4 lbfresh seasonal fruit, cleaned and hulled
- 3 lbgranulated white sugar
- 2 tbspbottled lemon juice
Judging the Set
Place a small dollop of the bubbling preserve onto your frozen saucer. If you push the edge with your finger and the surface wrinkles like silk, it is set.
The method.
Prepare the fruit
Mash the fruit in your pot with a potato masher. Add the sugar and lemon juice, stirring over low heat until the grains dissolve completely before cranking the heat.
The hard boil
Bring the mixture to a vigorous, rolling boil that doesn't disappear when you stir it. Use a wide pot so the steam escapes quickly.
Skim and test
Skim any grey foam from the surface with a metal spoon. Begin testing with the frozen saucer after 15 minutes of hard boiling.
Jar and process
Ladle the hot preserve into warm, sterilized jars, leaving a quarter-inch of space at the top. Seal tightly and submerge in boiling water for 10 minutes to finish the seal.
Other turns to take.
Spiced Stone Fruit
Add a stick of cinnamon or a few bruised cardamom pods during the boiling stage; remove before jarring.
Citrus Infusion
Add a tablespoon of finely grated zest at the very end of the boil for brightness.
When it doesn't go to plan.
Never double a jam recipe; it takes too long to boil down, which destroys the fresh flavor of the fruit.
Use a wide, shallow pan rather than a deep one to maximize surface area for evaporation.
Listen for the 'pop' of the lids as the jars cool; it is the definitive sound of a successful vacuum seal.
The ones that keep coming up.
Why did my jam turn out runny?
The fruit likely didn't reach the gelling point, or the pectin content of your fruit was too low. Try adding another splash of lemon juice earlier in the process next time.
Can I reduce the sugar?
Sugar is a preservative and a structural component in jam. Reducing it significantly will change the texture and shorten the shelf life of the jars.
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