There’s something magical about summer that makes me reach for the juiciest fruits I can find—and nothing shouts summer quite like watermelon. A few seasons ago, I found myself staring at a bowl of leftover watermelon slices after a picnic. They weren’t quite firm enough to serve again, but far too sweet and ripe to waste. That’s when the idea hit me: why not turn them into jam? This watermelon jam recipe was born out of that spontaneous kitchen moment, and now it’s a staple I return to every summer.
Why You’ll Love This Recipe
First of all, it tastes just like candy—but better. The natural sweetness of the watermelon, enhanced with just a little sugar and the citrusy brightness of lemon juice, turns into a jelly-like treat that’s both nostalgic and refreshing. Spread it on toast, swirl it into yogurt, or spoon it onto pancakes—it’s versatile, vibrant, and sure to become your summer favorite.
Versatile
This jam isn’t just for breakfast. You can serve it with desserts, spread it over crepes, or even mix it into your smoothies. Whether you love it warm over waffles or chilled on toast, it fits anywhere.
Budget-Friendly
One of the biggest benefits of this recipe is that you can use watermelon that’s a bit overripe or leftover from other meals. No waste, no fancy ingredients—just a few basics you already have at home.
Ingredients for Watermelon Jam
Here’s everything you need to create this simple, small-batch jam:
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4 cups chopped watermelon fruit – the star of the recipe, juicy and sweet
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1 cup sugar – just enough to enhance the natural sweetness
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4 tablespoons lemon juice – for that perfect tang and preservation
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2 tablespoons cornstarch – helps thicken the jam naturally
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1 teaspoon vanilla extract (alcohol-free) – adds depth and warmth to the flavor
This recipe gives you the freedom to create something delightful with minimal effort and maximum flavor. If you have an instant pot and a few extra slices of watermelon, you’re halfway there. The next steps will guide you through the easy process of turning fresh fruit into a sweet spread that brightens any dish.
Making this watermelon jam is much easier than you might think. I love how this recipe turns out every single time—reliable, simple, and bursting with flavor. Follow along with these steps to create your own small-batch watermelon jam at home.
Step 1: Prepare the Watermelon
First, chop your watermelon into small chunks. Make sure to remove any black seeds. Don’t worry if a few white seeds remain—they tend to float and can be removed later.
Step 2: Load the Instant Pot
Now, place the watermelon pieces directly into the Instant Pot. Pour in the sugar and lemon juice. Stir everything well. At this point, some remaining seeds may float to the surface—just skim them off with a spoon. It’s a small step that makes a big difference.
Step 3: Pressure Cook
Seal the Instant Pot lid and make sure the valve is in the sealing position. Select high pressure and cook for 15 minutes. This process softens the watermelon completely, releasing its juices.
Step 4: Natural Release and Mash
Once the cooking time is over, allow a natural pressure release. When it’s safe to open, carefully remove the lid. Stir the contents and use a potato masher to gently mash the fruit. Now stir in the vanilla extract (alcohol-free) for a beautiful depth of flavor.
Step 5: Simmer to Reduce
Using the sauté function, simmer the mashed watermelon mixture for about 10 to 12 minutes. Stir often and continue mashing if needed. Keep an eye out for more seeds floating up—they’re easy to scoop out during this stage. The mixture will begin to thicken slightly but still appear loose due to watermelon’s high water content.
Step 6: Make the Cornstarch Slurry
To get the jam to set properly, you’ll need to add a thickener. Take ¾ cup of the hot liquid from the Instant Pot and mix it with 2 tablespoons of cornstarch. Stir thoroughly to create a smooth slurry without lumps. This step ensures the jam sets beautifully without using pectin.
Step 7: Thicken the Jam
Now pour the slurry back into the Instant Pot. Stir immediately to combine it evenly. Continue to simmer for another 4 to 5 minutes, stirring frequently. You’ll notice the mixture thickening into a glossy, jam-like texture. At this stage, you can mash further if you prefer a smoother texture.
Step 8: Cool and Store
Press the Cancel button on the Instant Pot. Transfer the pot to a cooler area to stop cooking. Let the jam cool slightly. Then, spoon it into clean, dry, airtight glass jars. Since this is a small-batch recipe not intended for canning, refrigerate the jam and use within two weeks. You can also freeze it for extended storage.
Quick and Easy
From start to finish, this recipe takes less than an hour. It’s ideal for those days when you want something homemade without spending all afternoon in the kitchen.
Customizable
Prefer a chunkier jam? Mash less. Want a smoother spread? Blend it before adding the slurry. You’re always in control of texture and flavor. You could even add a dash of cinnamon or cardamom if you like a warm spice twist.
Crowd-Pleasing
This jam has been a hit at every summer brunch I’ve hosted. Kids love the candy-like sweetness, and adults enjoy how it’s different from traditional berry jams. One spoonful is never enough!
Whether you’re making it for your family or gifting a jar to friends, this watermelon jam captures the essence of summer in every bite.
FAQs
Can I use frozen watermelon instead of fresh?
Yes, you can use frozen watermelon. Just make sure to thaw and drain excess liquid before adding it to the Instant Pot. This helps control the moisture level and keeps the jam from becoming too runny.
Do I need to remove all the seeds?
Not all seeds need to be removed. Black seeds should be taken out before cooking, but white seeds are soft and often float during cooking, making them easy to scoop out later. A few white seeds left in won’t affect the final result.
Can I double the recipe?
This recipe is designed as a small batch, so doubling is not recommended unless you’re experienced with pressure cooking and batch adjustments. Overfilling the Instant Pot may affect cooking time and pressure release.
Why isn’t my jam thickening?
If your jam remains watery, you may need to simmer it a bit longer after adding the cornstarch slurry. Make sure the slurry is mixed well before adding, and stir continuously as it cooks to activate the thickening process fully.
How long does watermelon jam last in the fridge?
Once cooled and stored in airtight glass jars, this jam will stay fresh in the refrigerator for up to two weeks. For longer storage, keep it in the freezer and thaw in the fridge before use.
Can I use a stovetop instead of an Instant Pot?
Yes, you can. Cook the watermelon, sugar, and lemon juice in a heavy-bottomed pan over medium heat. Follow the same steps to mash, simmer, and add the slurry. Just remember to stir frequently to avoid burning.
Watermelon Jam – A Sweet Slice of Summer in a Jar
This small-batch watermelon jam is a vibrant, fruity spread made using fresh watermelon, sugar, lemon juice, and a touch of vanilla. Cooked in the Instant Pot and thickened with cornstarch, it’s a quick, simple recipe that brings summer flavor to your table. Ideal for toast, pancakes, and more—without any added pectin.
- Total Time: 55 minutes
- Yield: 32 tablespoons (approx. 2 cups) 1x
Ingredients
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4 cups watermelon (chopped, seeds removed)
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1 cup sugar
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4 tablespoons lemon juice
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2 tablespoons cornstarch
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1 teaspoon Vanilla Extract (Alcohol-Free)
Instructions
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Add watermelon, sugar, and lemon juice to Instant Pot. Stir thoroughly. Remove any seeds floating on the surface.
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Seal the lid, set to high pressure, and cook for 15 minutes. Allow natural pressure release.
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Open the lid carefully. Mash the watermelon with a potato masher. Stir in the vanilla extract.
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Use the sauté function to simmer the mixture for 10–12 minutes, stirring and mashing occasionally. Skim off any more seeds that rise.
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Remove about ¾ cup of liquid from the pot. Mix with cornstarch to form a smooth slurry.
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Pour the slurry back into the Instant Pot and stir well. Simmer for another 4–5 minutes until thickened.
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Press cancel, remove the pot from the base, and let cool.
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Transfer to clean, dry, airtight glass jars. Store in the fridge for up to 2 weeks or freeze for longer.
Notes
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This jam is not suitable for canning.
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Texture can be adjusted: mash less for chunky, more for smooth.
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Remove seeds early for best texture.
- Prep Time: 5 minutes
- Cook Time: 30 minutes