preserve · Preserve

How to Make Raspberry Jam

Raspberry jam needs just three things: raspberries, sugar, and time. Cook equal parts fruit and sugar over medium heat until it coats the back of a spoon and holds its shape when you drag your finger through it on a chilled plate. The whole process takes about 20 minutes of active cooking.

Total time: 30 min
Hands-on: 30 min
Difficulty: Easy

Ingredients

2 pounds fresh raspberries
2 pounds granulated sugar

Step by step

Prepare your raspberries. Use 2 pounds fresh raspberries. Look them over and remove any stems or leaves, but don't wash them unless they're visibly dirty. Wet berries make watery jam.
Combine fruit and sugar. Put the raspberries in a heavy-bottomed pot with 2 pounds granulated sugar. Let this sit for 10 minutes so the sugar starts drawing out the juices.
Start cooking. Turn the heat to medium and stir gently until the sugar dissolves completely. The mixture will be quite liquid at first.
Bring to a rolling boil. Increase heat to medium-high. The jam will bubble vigorously. Stir occasionally to prevent sticking. You'll see foam forming on top.
Skim the foam. Use a large spoon to remove the white foam that rises to the surface. This keeps your jam clear and bright.
Cook until set. Keep cooking for 15-20 minutes total, stirring regularly. The jam is ready when it coats the back of a spoon and doesn't immediately fill in when you draw your finger across it.
Test for doneness. Drop a small spoonful on a chilled plate. If it holds its shape and wrinkles slightly when you push it with your finger, it's done.
Fill jars while hot. Ladle the jam into sterilized jars, leaving 1/4 inch headspace. Wipe the rims clean and seal with new lids.

Tips & troubleshooting

Use a pot that's wider than it is tall. This helps the water evaporate faster and prevents the jam from cooking too long.
Keep a small plate in the freezer before you start cooking. It's the most reliable way to test if your jam has reached the proper consistency.
Don't double the recipe. Large batches take too long to cook and you'll lose the fresh fruit flavor.
The jam will thicken more as it cools, so err on the side of slightly underdone rather than overcooked.
Store unopened jars in a cool, dark place for up to a year. Once opened, keep refrigerated and use within 3 weeks.

Variations

Low-Sugar Raspberry Jam. Use 3 parts fruit to 1 part sugar, plus 1 package powdered pectin stirred in during the last few minutes of cooking. The texture will be softer but the raspberry flavor more pronounced.
Seedless Raspberry Jam. Push the cooked jam through a fine-mesh sieve or food mill while still hot to remove seeds. You'll lose about 1/3 of the volume, but get perfectly smooth jam.
Raspberry-Vanilla Jam. Add 1 vanilla bean, split and scraped, during the last 5 minutes of cooking. Remove the pod before jarring.
Mixed Berry Jam. Replace up to half the raspberries with blackberries, blueberries, or strawberries. Keep the same sugar ratio and cooking method.

Questions

Can I use frozen raspberries?: Yes, but thaw them completely first and drain off excess liquid. Frozen berries release more water, so your cooking time might be a few minutes longer.
Why didn't my jam set properly?: Usually because it didn't cook long enough or the fruit was overripe. Underripe fruit has more natural pectin. You can re-cook runny jam with a little lemon juice to help it set.
Do I need to add lemon juice?: Not with raspberries. They're naturally acidic enough. Lemon juice is more important with low-acid fruits like strawberries or sweet cherries.
How do I know if my jars sealed properly?: The center of the lid should be slightly concave and shouldn't move when you press it. You'll often hear the 'pop' of the seal forming as the jars cool.
Can I reduce the sugar?: You can, but sugar isn't just for sweetness. It helps the jam set and preserves it. Going below a 2:1 fruit-to-sugar ratio means you'll need to add commercial pectin or accept a softer set.