Cooper starts out simple, with a basic red strawberry jam that's as right on fancy scones as on kid-friendly PB&J.
You can follow these steps for any jam that relies on liquid pectin -- let whatever is fresh at the market (or garden!) guide your decision.
One more of Cooper's pro tips: "As with all fresh fruit, use slightly or just fully ripe berries since riper fruit contains more liquid and less natural sugar, which can result in a runny jam. In winter, it may be necessary to purchase extra fruit to ensure having enough at the right stage of ripeness all at once."
1. Prepare the fruit—wash, pat dry, and hull about two quarts of firm berries. Crush them completely, one layer at a time. A potato masher works well for this.
2. Measure 3 ¾ cups crushed berries and their juice into a large saucepan or kettle. The jam will boil up as it cooks so use a good-sized pan.
3. Add to the pan:
a. 7 cups (3 pounds) of white sugar
b. ¼ cup lemon juice (fresh is best)
4. Place the pan, uncovered, on a cold stove, turn the heat high, and bring to a full rolling boil, stirring continually. Boiling fruit will rise up in the pan very rapidly, so watch carefully.
5. Lower the heat slightly and boil hard for one minute, stirring continually. Foam will develop on the surface. Carefully spoon this off into a saucer and save to spread it on bread later for a special treat. It will not hurt the jam if you keep it in the pan, but it will not make as pretty a finished jar.
6. Remove the pan from the heat and at once stir in ½ bottle of pectin or one pouch from a two-pouch box.
7. Stir the jam and skim off foam for 5 minutes. The foam will partially dissolve by itself as the jam cools, but for appearance's sake, it should be removed.
8. Gently ladle the jam into sterile jars and seal at once.
Yield: 8 to 10 half-pint jars of jam