Make fruit jam with Jun Jun de Guzman
You only need three ingredients to make fruit jam: flesh from fruit in season, white sugar, and an acid. The basic ratio is 100 percent fruit (processed until chunky), 80 to 90 percent sugar, and two to three percent acid (like lemon or calamansi juice).
You can also add pectin to the mix (about 10 grams). Pectin is naturally present in fruits, and is also available in powdered form in specialty shops. Adding pectin to jam while cooking will make it thicken and set. If the fruit you are using already has a good amount of pectin in it, there is no need to add powdered pectin to make jam. Fruits high in pectin include apples, guavas, and citrus fruits. If you don’t want to use pectin when making jam using low-pectin fruit (like strawberries, pineapples, and other soft fruits), simply boil the fruit mixture until reduced and thick (about 220ºf).
To preserve your jam, can it! Boil the canning jar and lid for 10 minutes then fill with warm jam. Screw on the lid, but not tightly (the contents will expand and the jar could break if the lid is screwed on too tightly). Simmer jar for 15 to 20 minutes, making sure it is completely submerged in water. Remove from water and cool completely. Press the top of the lid; it should stay put, which means the jar is sealed airtight. Store at room temperature for up to one year.