Watermelon Jam

A thing of beauty is a joy for my tummy

A thing of beauty is a joy for my tummy!

I first heard about watermelon jam last summer, via Pinterest. The picture looked fantastically summery and wonderful, and though I didn’t have the energy to get around to it just then, I filed it away mentally for later.

Last month, I got my chance. I pulled that pin back out, and read up on everything watermelon jam-y. The recipe in that post is based on one from another blog, and after reading them both, I was ready.

Let me just say that that experience was horrific. The recipe calls for boiling until the mixture reaches 220 degrees. At my house, that took at least 30 minutes, and by that point, the whole mess smelled strange and tasted worse. The point of the boiling was ostensibly to ensure that the jam would set, but when I poured it into my jars, it was SO thick that it could have been used to apply wallpaper. Once it had cooled, it tore through toast. We won’t even talk about the flavor. It was just terrible. (I should add that I used 4 cups sugar and 1/2 cup lemon juice, like Blondie suggests. Don’t.)

This week, I picked up a sweet and fabulous watermelon, and I decided it was time to give it one more shot. I have a strawberry jam recipe I love to pieces, and I figured just following that might do the trick. Turns out I was right! Thank you, BHG. Here’s the winner, kids:

Watermelon Jam
Based on recipes from Food in Jars and Better Homes and Gardens You Can Can


6 cups watermelon puree (about 1/2 large seedless watermelon)
1/3 cup lemon juice (bottled is fine here)
1/2 tsp butter
1 1.75-oz box pectin
5 cups sugar

5 pint or 10 half-pint jars


  1. Place jars, rings, and lids in dishwasher on sterilize or rinse/dry cycle.
  2. Fill a big, flat-bottomed pot with water, full enough to cover jars, and set it over high heat. You’ll want it boiling and ready fairly soon.
  3. While jars are sterilizing, cut watermelon into chunks and puree using food processor or smash with a potato masher or food mill. You can strain the puree if desired, to get rid of any little seeds, but I didn’t bother. Continue adding puree to make 6 cups.
  4. Check on your jars. They should be about finished in the dishwasher. When they are, leave them in the hot dishwasher, but remove the flat lids. Place them in a small saucepan with just a little very hot water. Place that pan over high heat to simmer.
  5. In a large pot (it can even be the one you plan to process your jars in, if it has to be, but then obviously remove the water), mix puree, lemon juice, pectin, and butter and bring to a rolling boil, stirring constantly.
  6. Add sugar all at once. Return to a full rolling boil for 1 minute, stirring constantly. Remove from heat and skim off foam with a metal spoon.
  7. Ladle immediately into hot, sterilized jars, leaving 1/4″ empty space at the top. Wipe any drips from the rims so that they’re absolutely spotless. Using tongs or a magnetic wand, remove a lid from the hot water in the small pan and place it on top of each jar, and then add a ring, screwing on loosely. The rings don’t need to be tight yet.
  8. Place as many jars as desired in the big, flat pot filled with water (it should be boiling softly by now–if it’s at a rolling boil, turn it down. You just barely want water movement). Once you’re finished adding jars, your water level should be at least an inch higher than the top of your jars.
  9. Allow the water to boil very softly for 10 minutes. Then remove jars from water and let them cool on a wire rack.
  10. The lids will pop if they’ve sealed correctly. Sometimes they pop while they’re in the water bath, sometimes right after being removed, and sometimes not for up to a few hours later. If it’s been 24 hours and one hasn’t popped, something bad happened–stick it in the fridge and eat it right away.
  11. After the jars have cooled, tighten up the rings and store at room temperature for up to 1 year.

Note: there was some discussion in the original recipe about how this could take up to a week to set. Obviously, that wasn’t the case with my first attempt. We’ll see how it goes this time. I’ll update you when I find out!

5 thoughts on “Watermelon Jam

  1. Good timing, Nicki! So, it didn’t gel after a week. Just yesterday, I dumped it all back in a pot and added another package of pectin and boiled it for 5 minutes and tried again. It’s definitely thicker this time, but still not as thick as my jams usually are? It seems thicker today than it was yesterday, though, so I’m going to give it a few more days and see what happens. This is one crazy experiment, but I’m dying for it to turn out–it tastes so fabulous!

  2. I just tried this and altered it slightly, it worked and set when cooled🙂 After reading the comments I used two boxes of pectin and 1 cup of UltraSet. What a unique taste! It reminds me of a watermelon jolly rancher candy😛 I have 4 yr old daughters that are going nuts over this!

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