Every year I make a little more jam, a little more experimenting with seasonal fruits at their peak. And every year I wonder why I don’t do this more often. It’s really so easy, and besides a funnel, a candy thermometer, and a really large pot, there’s not a lot of special equipment involved. My little jam operation here at kitchen central is small production; sometimes only enough jam to fill two 16-ounce jars.
Jam making is essentially nothing more complicated than preserving fruit with sugar. The sugar also helps to set the gel of the jam when the mixture is heated to eight degrees above the boiling point (called, fittingly, the gel point temperature). At sea level, that equates to 220 degrees F (212 + 8 = 220). At 6500 feet above sea level where we spend a lot of time at Tahoe, the set temperature is 208 degrees F. Pectin is the other key component of getting a good set. Pectin is a natural, water-based substance present in ripe fruit which is essential for thickening preserves. It varies by the type of fruit, which is one of the drivers to adding liquid or powdered pectin to low-pectin fruit, or combining a low pectin fruit like strawberries with a high pectin vegetable like rhubarb.
A few cooking notes:
This strawberry jam doesn’t use any pectin and puts strawberries in the starring role, so it’s critical to get the jam temperature up to the gel point for your altitude unless you’re shooting for jam soup. If you’re not sure exactly what your altitude is, just bring a pot of water to a boil. Immediately take the temperature of the water using a candy thermometer and add eight degrees.
The lemon juice sharpens the fruit flavor, and is believed to activate its gelling action.
This jam is a little liquidy, but is so loaded with strawberries it feels like the right balance to me. But if you prefer a little more set to your jam, add some pectin. I don’t have a specific recommendation for how much since a) I haven’t actually done it with this recipe, and b) it depends on your personal preference for degree of set.
Lastly, I macerate the fruit in the sugar overnight, a trick I picked up from Christine Ferber in her wonderful ‘Mes Confitures’ book. She claims a gradual absorption of sugar promotes preservation of the texture of the fruit, and I’m inclined to agree. If you’re pressed for time and need to combine the ingredients and make jam immediately, feel free. No adjustment to the recipe is required.
Strawberry Balsamic Preserves
Makes two 16-ounce jars
- 2 pounds strawberries, hulled, net weight, halved (I started with 2 1/2 lbs to get to 2 lbs net wt)
- 3 cups sugar
- 2 tablespoons lemon juice (1 lemon)
- 2 tablespoons balsamic vinegar
Combine the first three ingredients together in a stainless bowl, and macerate overnight.
The following day, pour the fruit and macerating liquid into a wide-mouthed stainless or copper pot. Add the balsamic vinegar, and bring to a boil, stirring frequently to prevent the fruit from sticking to the bottom of the pot, and skimming the foam from the top using a metal spoon. The best way to remove the foam from the spoon is to dip it into a bowl of water. The spoon will immediately be ready for additional skimming.
Using a candy thermometer, bring the temperature to the gel point temperature for your altitude which is 8 degrees higher than the boiling point of liquid (220 degrees F at sea level, 208 degrees F at 6500 feet above sea level).
Boil for an additional 2 – 3 minutes.The strawberries should be somewhat translucent, but full of color. The foaming action should stop, and the bubbles from the boiling should become larger and lazier bubbles. (This is not a hard gelling jam, so traditional gel tests may not be accurate indicators that the preserves are ready.)
Immediately fill sterilized jars using a ladle and a funnel, wipe the lip of the jar clean with a clean cloth, screw on the lid. If there are any preserves on the lip of the jar, you will not get a good seal. Keep on the counter until it seals, about an hour. Enjoy!