How to Make Jam

Mixed Berry Jam — Photo:
Sophia Yartseva / Getty Images

Active Time:

45 mins

Total Time:

2 hrs

Yield:

4 half-pints

Making jam is a time-honored cooking tradition that may sound more complicated than it actually is. The hands-on time and canning equipment needed are minimal, and the reward is well worth the effort of prepping your favorite fruit and simmering it until it thickens.

This jam recipe is an excellent place to start. You can use any combination of berries you prefer here. Keep in mind that strawberries have less pectin than blueberries and other berries, and won’t set as thick on their own without adding pectin. I call for a range of sugar, because the amount needed will depend on how sweet the fruit is. Start with two cups of sugar, and add a bit at a time as you taste the jam until it tastes the way you want.

I use bottled lemon juice in this recipe; it has a consistent acidity level that conforms to USDA guidelines for making shelf-stable jam. But if you are storing your jam in the refrigerator and using it within a month, feel free to use fresh lemon juice instead.

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Ingredients

6 half-pints blueberries, blackberries and/or raspberries (about 3 pounds)
2 to 3 cups granulated sugar
1/4 cup bottled lemon juice
1 vanilla bean, sliced in half lengthwise (see NOTE)

Directions

Macerate the berries

Matt Taylor-Gross / Food Styling by Debbie Wee

Taste berries before getting started to determine how much sugar to use; if fruit is on the tart side, use 3 cups of sugar. Place berries in a large container or bowl. Add sugar and lemon juice, stirring until evenly mixed. Split vanilla bean pod lengthwise; scrape seeds with the back of a paring knife. Add seeds and vanilla pod halves to fruit mixture. Cover berries and refrigerate for 1 hour or up to 24 hours.

Cook the fruit

Matt Taylor-Gross / Food Styling by Debbie Wee

Pour steeped berries along with any syrup and residual sugar into a wide, heavy-bottomed pot or a large (14-inch) skillet. Remove vanilla pod. Bring berries to a boil over medium-high heat. Have a heavy-duty spoon or spatula at the ready. For the first few minutes, it will seem like nothing is happening. But as the sugar dissolves, you’ll notice more syrup and mixture will begin to bubble. Stir mixture regularly and reduce heat as needed to minimize splattering. For several minutes, the mixture will bubble like crazy. A foam may form; skim it and discard. Keep stirring. As the water evaporates and the temperature rises, the jam will thicken.
As you mix, feel free to mash the mixture, depending on your preferred final texture. Continue cooking until jam thickens and gels, about 20 minutes. Jam will have a sheen and any foam will have moved to edges.

Test your jam’s readiness

Matt Taylor-Gross / Food Styling by Debbie Wee

There are three ways to see if your jam is ready. Take its temperature; jam will be 220°F on a candy or instant-read thermometer when it is ready. Drag a wooden spoon or rubber spatula through the jam; if it recedes like a low tide exposing the surface of the pan, then it is ready. Finally, you can do the “zip line” trick: Lift a wooden spoon or rubber spatula out of the cooked fruit and turn it on its side, allowing it to drip. When the drops slowly meet “along the line” and form one or two thick globules, the jam is ready.
Remove pot from the heat and let sit for 5 minutes. Jam is ready to eat and can be stored in glass jars in the refrigerator for up to 1 month. Let jam cool completely before storing in the refrigerator. Keeps for about 1 month.