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What Is Jam?
Jam is made from pieces of fruit, usually chopped or crushed and cooked with sugar until the pectin releases and the mixture is thickened to a spreadable consistency. The most common fruits used to make jam are berries, grapes, and stone fruit. Jam is ideal for spreading onto toast and filling pastries.
What Ingredients Do You Need to Make Jam?
- Fruit: If you’re jam making for the first time, it’s best to start with high pectin types of fruit like citrus, apples, cranberries, currants, plums, and quince. These fruits will naturally thicken easier when cooked with sugar, which is essential for good results.
- Sugar: Besides sweetening the flavor, sugar works with the pectin and fruit acids to create the gel texture that indicates a proper jam. Sugar also acts as a preservative that maintains the color of the fruit and inhibits mold growth. Low-sugar jams often require added pectin to firm up.
- Pectin: Commercially produced pectin is sometimes added to jam when the fruit doesn’t contain enough natural pectin of its own. Pectin is a naturally occurring substance found in berries, apples, and other fruit. When cooked to a high temperature in combination with acid and sugar, it forms into a gel. Learn more about pectin, including appropriate substitutes, here.
What Equipment Do You Need to Make Jam?
- A heavy-bottomed large pot or saucepan: Using a heavy pan keeps the fruit from scorching over heat, while also providing a larger surface for evaporation. The key to making jam is reducing water in the fruit, helping it to thicken with the sugar, so a thick-bottomed pot will let you cook for a longer period without burning the contents.
- Jam jars: Use heatproof sealable glass pint jars (easy to sterilize) for storing jam after cooking. Jam has to be hot when it goes into its sterilized jar and sealed, otherwise it can become moldy. Part of the preserving process is for all the air in the jam to escape and for the lid to then be sucked down into the vacuum, creating a strong seal.
- Heatproof spatula or wooden spoon: Heatproof cooking utensils don't quickly heat to high temperatures or chemically react with acidic foods as their metal counterparts do. They don't melt or release chemicals into hot food as plastic does.
What Fruits Can You Jam?
When it comes to selecting fruits to jam, the sky’s the limit. You can make fruit jam out of a large variety of fruit:
- Citrus, like oranges and kumquats. Citrus, particularly orange, is high in pectin.
- Pome fruit, including apples and pears. Pome fruit feature high levels of pectin.
- Berries, like strawberries, raspberries, and blueberries. These softer fruits are lower in pectin. Try Chef Dominique Ansel’s classic strawberry jam recipe here.
- Stone fruit, like apricot. Apricots are low in pectin and require more sugar to gel.
- Tropical fruits, like pineapple and passionfruit. Tropical fruits contain almost no pectin; combine them with high-pectin fruits or add extra sugar to reach desired consistency.
Can You Make Jam Without Pectin?
You can make jam without added pectin two ways:
- Use high pectin fruit, like apples or oranges.
- Combine a low pectin fruit with lemon juice, so the natural pectin from the citrus reacts with the sugar present in the fruit.
In general, barely ripe fruits will have higher pectin and require less sugar than ripe fruits with less pectin. You’ll need to add more sugar to the ripe fruit to help it thicken, and a little extra lemon juice to balance the sweetness.
4 Tips for Making Perfect Homemade Jam
- Clean and sterilize your jars. Making sure you clean your jars well will maintain the shelf life of the jam and protect your food from spoilage. Sterilize jars by washing in hot soapy water, rinse, and drain. Place on oven racks and heat at 250°F for 10-15 minutes.
- Use the right kind of sugar. Granulated or preserving sugar is ideal for making jam. Granulated works well with high pectin fruits, but preserving sugar has larger sugar crystals that help set low-pectin fruits.
- Check the level of pectin in your fruit. Pectin is found naturally in fruit and when cooked with sugar, it thickens and sets the jam. Citrus fruit, apples, and plums have high pectin levels. Softer fruits like peaches, cherries, and grapes have lower levels. To balance out low pectin fruit, either combine it with high pectin fruit (a few squeezes of lemon juice works), or add commercially made pectin powder. Using slightly underripe fruit will have increased pectin levels.
- The wrinkle test. The setting point for jam is 220°F. Test this with a candy thermometer or try the “wrinkle test.” Before cooking the jam, place a plate in the freezer. Once you think your jam is ready, spoon a little onto the plate. If the surface of the jam wrinkles when you nudge it with your finger, it’s done.
How to Store Homemade Jam
When jam is cooled and stored covered in clean jars, it can last up to a month in the refrigerator or up to a year in the freezer. Canning prolongs the shelf life considerably. If you process by canning in a boiling water bath, you can expect up to two years of shelf life when stored in a cool, dry place.
Homemade Berry Jam Recipe
Prep Time5 min
Total Time25 min
- 1 pound fresh berries (strawberries, blueberries, blackberries, or a mix)
- 3/4 cup granulated sugar
- 2 tablespoons fresh lemon juice
- Pinch of salt
- Place a heatproof plate in the freezer.
- Clean berries, trimming if necessary. Cut into 1-inch chunks. Combine berries, sugar, and salt in a large heavy-bottomed pot. Place the pot over low heat, dissolving the sugar. Increase to a high heat, bring to a full rolling boil while stirring and mashing fruit with a potato masher or fork. Add lemon juice; lower heat to a simmer, stirring often, until thickened and mixture clings to a spoon, about 20 minutes. Skim any scum that rises to the surface.
- Take the pot off the heat and spoon a little jam onto the plate. Let sit for one minute, then push the blob of jam with a finger. Once the surface of the jam wrinkles, then it has set. If it’s still liquidy, then continue to cook for a few minutes until testing again.
- Ladle finished hot jam into two clean 8-ounce jars, let cool completely to room temperature if storing in the fridge (up to one month), otherwise proceed with a canning method for longer storage. Learn how to can with our guide here.