While recipes using pectin are my favorites for making quick batches of tasty jams or jellies with less sugar and less fuss, the flavor of jam made the old-fashioned way, with lots of sugar and cooking time, is a delicious occasional indulgence.
8 cups strawberries, crushed
6 cups sugar
Lemon juice (optional)
Rinse (do not soak) berries and drain well. Remove hulls. Crush berries using a pastry blender or potato masher, but don’t puree them–jam has chunks of fruit in it.
Measure berries into a large, heavy-bottomed saucepan. If fruit is very ripe and sweet, add 1 tablespoon lemon juice for every cup of crushed berries.
Over medium heat, stirring occasionally, bring fruit to a gentle boil. Add sugar, stirring constantly until sugar dissolves. Then, increase heat to bring the mixture quickly to a boil. Keep mixture at a rapid boil, stirring constantly to prevent burning, until mixture passes one or more of the tests for doneness (see sidebar).
Remove from heat and skim off any foam. Using a wide-mouthed funnel and a ladle or measuring cup, fill hot, sterilized jars, leaving a one-quarter-inch headspace. Use a damp (not wet) paper towel to wipe the rims.
How to prepare canning jars
Wash canning jars, new lids and bands in hot, soapy water and rinse well. (Use new jars or inspect used jars well, choosing only those free of cracks and chips.) Dry bands and set aside.
Follow the manufacturers’ directions for preparing the lids.
Time this next step so that jars are dry but still hot right before you are ready to fill them. Using a wide, metal saucepan with a flat bottom or a metal cake pan, heat 2 to 3 inches of water until just simmering. Invert clean, rinsed jars in the water and simmer for 10 minutes.
Shortly before you are ready to ladle the jam into the jars, remove them from the water, turn right-side up, and allow to dry before filling. They should still be quite hot when you fill them.
Has my jam jelled?
Thermometer test: To use a candy, deep-fat or jelly thermometer, first determine the jellying point for your altitude first. Boil some water, noting the temperature at which the water boils. Add 8 degrees Fahrenheit to find the jelling point for your jam or jelly (usually around 220 degrees).
Spoon test: Dip a large metal spoon into boiling jam or jelly. Hold it at least 12 inches above the saucepan, out of the steam, and hold the spoon upside down. If the jam is done, it will sheet from the spoon (run off evenly, leaving a syrup behind).
Refrigerator test: Place a small spoonful of jam onto a chilled plate and place in the refrigerator. If the jam sets up (becomes thick and somewhat firm) after two or three minutes, it is done.