This strawberry jam recipe uses an overnight maceration (soaking time) and homemade pectin to keep the sugar amount moderate and the cooking time low. The result is a brightly colored and flavored jam that honors the fruit it is made with.
Strawberries are a low pectin fruit, which means that they don't gel well on their own. But adding commercial pectin often requires adding huge amounts of sugar. The alternative is a super long cooking time.
This recipe is an excellent way to make strawberry jam without having to buy pectin or rely on heavy sugar content or long cooking times that result in loss of flavor and color.
- Wash the strawberries and slice off their hulls (the green bits). If the strawberries are very small, leave them whole. Otherwise, slice into halves or quarters. It is also fine to use frozen berries for this recipe.
- Put the cleaned strawberries into a non-reactive pot. That means no unenameled cast iron, aluminum, or copper, which could result in a dark, discolored jam. Enameled pots, stainless steel, and Pyrex or other heat-proof glass are fine.
- Add the sugar and mix well. Cover and refrigerate for 8 hours or overnight. This long maceration reduces the cooking time later, resulting in a fruitier, more brightly flavored and colored jam.
- Sterilize the canning jars by immersing them in boiling water for 15 minutes. Do not boil the canning lids but rather drop them into the hot water with the jars after you have turned off the heat.
- The strawberries will have released a lot of their juice during their maceration. Stir the macerated berries and their juice to liquefy any still-undissolved sugar.
- Stir in the homemade pectin and the lemon juice or cider vinegar.
- Place the pot with the strawberry mixture over high heat and cook, stirring frequently, until the mixture reaches the jell point.
- Ladle the jam into the sterilized jars, leaving 1/2-inch head space between the surface of the jam and the rims of the jars. Screw on the canning lids.
- Process in a boiling water bath for 5 minutes. If you used 2-piece canning lids, remove the jars from the boiling water bath and let cool completely, undisturbed. If you used 1-piece canning lids, do not remove the jars from the pot but rather let them cool completely in the water.
The sealed jars can be stored at room temperature, but once opened, keep them in the refrigerator just as you would with store bought jam. Sealed, the jam will keep for 1 year. The jam is still safe to eat after that, but the quality declines.