Fresh Watermelon Jello Slices (Without Gelatin)

5 from 4 votes
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How to make fresh watermelon jello without gelatin, using watermelon juice and agar-agar for a healthy, delicious, all-natural, vegan jello! Serve in the rind for show-stopping watermelon jello slices, pour into watermelon jello shots, or simply set in a large jello mold for a fruity, summery treat!

Watermelon jelly cut into slices

As the end of watermelon season edges nearer (albeit slowly right now), I’m trying to make the most of this fruit as its sweetest and most ripe. So far this summer, I’ve enjoyed fresh watermelon salsa with tortilla chips, watermelon feta salad, and watermelon juice (for delicious summer mocktails/cocktails). Then again this week – with yet another melon to use, I turned to fresh watermelon granita (a simple and refreshing semi-frozen dessert) and this watermelon jello (without gelatin).

This vegan watermelon jello recipe ditches the sugary unnatural store-bought jello. Instead, it relies on fresh watermelon juice and agar-agar to make a simple, fresh, and flavorful sugar-free watermelon jello. Of course, if your melon isn’t particularly sweet (or you just have a sweet tooth), then feel free to add a little sugar, unrefined sugar, or even sweetener – like erythritol.

A slice of wateremelon jelly

No matter what you decide, this homemade version is still miles healthier than any store-bought chemical-filled, artificially flavored version. There are even several ways to adapt the recipe with extra ingredients, whether you want a boozy twist, slightly floral notes, or just a little “zing”!

Even better, once mixed up, you can decide whether or not to serve this up as jello-filled watermelon slices, jello shots, or simply in a large jello mold. Either way, this is a great way to impress at parties, BBQs, potlucks, and cookouts!

For more fruity, summery dishes, you might also like this grilled peach burrata salad, pineapple cucumber salad, pineapple lemonade, or mango or peach ice cream!

The Ingredients

  • Watermelon: use a fresh, ripe watermelon. Seedless varieties are best, as you avoid having to sieve the mixture, but seeded varieties are fine too! Yellow watermelon will work too.
  • Agar-agar: this watermelon jello has been made vegan by substituting gelatin for agar-agar. I recommend using powdered agar, not the flakes (as flakes require more and affect flavor more). However, if you only have flakes, you’ll need to increase the amount. Remember 1 tsp agar powder = roughly 1 Tbsp agar flakes.
Ingredients for watermelon jelly

Looking for more ways to experiment with agar-agar? I love to use it to set my tart recipes like this vegan earl grey blueberry tart, two-layer strawberry coconut tart, and chocolate cherry ‘black forest’ tart!

Optional Add-Ins and recipe variations

  • Sugar: if the watermelon is sweet enough, you may not need any at all (I didn’t). However, you can add sugar (or a sugar-alternative like erythritol/Stevia) to the juice when heating. Use cane sugar, coconut, etc. However, each will affect the flavor in different ways.
  • Lemon/Lime: a little lime zest and juice added to the jello mixture will enhance flavor and add a little zing.
  • Rosewater: just a little rosewater will help to subtly fragrance the watermelon jello recipe. I recommend adding 1 tsp and only then increasing to taste. Alternatively, you could add a few drops of rose extract.
  • Alcohol: for boozy watermelon jello shots, you could use vodka, tequila, or rum. Just note that you’ll need to add extra agar agar to make up for the excess liquid. Use around ½ tsp agar powder for ½-3/4 cup alcohol (otherwise, the watermelon jello slices won’t be stiff enough). If you want vegan watermelon jello, make sure your alcohol is vegan!

How to Make Watermelon Jello

Step 1: Prepare the watermelon

First, slice the watermelon in half and juice it. To do so, just scoop out the watermelon flesh from the rind, place it in a large bowl and use an immersion blender; or use a large blender/food processor. Blend until smooth.

If you plan to use the watermelon rind for the jello, use a spoon to gently scrape all the flesh from the melon until the light rind.

Then strain the juice to remove any seeds/pulpy bits. I use a nut milk bag and manually squeeze- but a fine-mesh sieve would also work.

Step 2: Prepare the jello mixture

In a large skillet or saucepan, combine the watermelon juice and agar-agar and heat over medium, whisking constantly, until the agar has completely dissolved and slightly warmed up. This process will take just a few minutes.

Once melted, work quickly to pour the mixture into the watermelon rind OR the mold of your choice. If you’re making watermelon shots, then add to individual shot glasses.

Steps for making watermelon jelly

Then, allow the mixture to cool down and chill in the refrigerator until fully set. The amount of time this takes will depend on what mold you’ve used (i.e., watermelon jello shots will take far less time than using the watermelon rind).

Then use a chilled sharp knife (place it in the freezer for a few minutes) to slice the watermelon jello slices and serve! Serve alone, studded with mini chocolate chips (as “seeds”), or top with a bit of whipped coconut cream and berries!

How to Store?

Once prepared, the watermelon jello will store for several days (3-4) in the fridge. In fact, you don’t even have to fully slice the melon slices until you’re ready to serve if preferred.

Watermelon jelly slices

Recipe Tips and FAQs

  • For smaller slices: Instead of watermelon rind, you can pour the watermelon jello into scooped out lime halves, then slice into wedges once set. Though the jello will become tarter nearer to the rind.
  • Trim the slices: Even if you pour the watermelon jello to the top of the watermelon rind, it will shrink as it sets. For “pretty” slices, I recommend trimming off the ends of the rind after cutting the slices.
  • Leaving some flesh in the slices: it’s possible to leave a thin 1-inch layer of watermelon flesh in the melon before adding the jello. If you have any extra, you can just pour it in a separate mold. However, I’ve found that the jello is more likely to slide off the rind when flesh remains.
  • Making the perfect slice: it’s important to slice fairly substantial pieces (around 1-inch thick minimum. Slice them too thin, and the jello will flop over rather than standing.
  • What is agar-agar powder? It is a substance made from seaweed (specifically red algae) that becomes gelatinous when heated, similarly to gelatin – yet is 100% plant-based. In comparison, it sets slightly firmer than gelatin and doesn’t require being chilled to fully set.
  • Can I substitute the agar? Technically you could use veggie gel (the vegetarian version of gelatin) or gelatin (if you use animal products). However, the amounts will differ (written on the packs), and I can’t guarantee results, as I haven’t tried.

Refreshing Fruity Summer Drinks

Or browse through my complete list of 40+ summer drink recipes.

If you try this simple vegan watermelon jello recipe, I’d love to hear your thoughts/questions below. Also, I’d appreciate a recipe card rating below, and feel free to tag me in your recipe recreations on Instagram @Alphafoodie!

Fresh Watermelon Jello Slices (Without Gelatin)

5 from 4 votes
By: Samira
How to make fresh watermelon jello without gelatin, using watermelon juice and agar-agar for a healthy, delicious, all-natural, vegan jello! Serve in the rind for show-stopping watermelon jello slices, pour into watermelon jello shots, or simply set in a large jello mold for a fruity, summery treat.
Total Time: 15 minutes
Servings: 8 or more depending on how it’s served

Ingredients 
 

  • 4 cups watermelon juice use about 46 oz/1.3 kg wateremelon
  • 0.14 oz agar-agar 1.5 tsp

Instructions 

Step 1: Prepare the watermelon

  • Slice the watermelon in half and juice it. To do so, just scoop out the watermelon flesh from the rind, place it in a large bowl and use an immersion blender; or use a large blender/food processor. Blend until smooth.
    If you plan to use the watermelon rind for the jello, use a spoon to gently scrape all the flesh from the melon until the light rind.
  • Strain the juice to remove any seeds/pulpy bits. I use a nut milk bag and manually squeeze. A fine-mesh sieve would also work.

Step 2: Prepare the jello mixture

  • In a large skillet or saucepan, combine the watermelon juice and agar-agar and heat over medium, whisking constantly, until the agar has completely dissolved. This process will take just a few minutes.
  • Once melted, work quickly to pour the mixture into the watermelon rind OR the mold of your choice. If you're making watermelon shots, then add to individual shot glasses.
  • Allow the mixture to cool down and chill in the refrigerator until fully set. The amount of time this takes will depend on what mold you've used (i.e., watermelon jello shots will take far less time than using the watermelon rind).
  • Then use a chilled sharp knife (place it in the freezer for a few minutes) to slice the watermelon jello slices and serve!
    Serve alone, studded with mini chocolate chips (as "seeds"), or top with a bit of whipped coconut cream and berries!

How to Store?

  • Once prepared, the watermelon jello will store for several days (3-4) in the fridge. In fact, you don't even have to fully slice the melon slices until you're ready to serve if preferred.¾

Notes

  • For smaller slices: instead of watermelon rind, you can pour the watermelon jello into scooped out lime halves, then slice into wedges once set. Though the jello will become tarter nearer to the rind.
  • Trim the slices: even if you pour the watermelon jello to the top of the watermelon rind, it will shrink as it sets. For “pretty” slices, I recommend trimming off the ends of the rind after cutting the slices.
  • Leaving some flesh in the slices: it’s possible to leave a thin 1-inch layer of watermelon flesh in the melon before adding the jello. If you have any extra, you can just pour it in a separate mold. However, I’ve found that the jello is more likely to slide off the rind when flesh remains.
  • Making the perfect slice: it’s important to slice fairly substantial pieces (around 1-inch thick minimum). Slice them too thin, and the jello will flop over rather than stand.
  • What is agar-agar powder? It is a substance made from seaweed (specifically red algae) that becomes gelatinous when heated, similarly to gelatin – yet is 100% plant-based. In comparison, it sets slightly firmer than gelatin and doesn’t require being chilled to fully set.
  • Can I substitute the agar? Technically you could use veggie gel (the vegetarian version of gelatin) or gelatin (if you use animal products). However, the amounts will differ (written on the packs), and I can’t guarantee results, as I haven’t tried.
 
Optional Add-Ins and recipe variations:
  • Sugar: if the watermelon is sweet enough, you may not need any at all (I didn’t). However, you can add sugar (or a sugar-alternative like erythritol/Stevia) to the juice when heating. Use cane sugar, coconut, etc. However, each will affect the flavor in different ways.
  • Lemon/Lime: a little lime zest and juice added to the jello mixture will enhance flavor and add a little zing.   
  • Rosewater: just a little rosewater will help to subtly fragrance the watermelon jello recipe. I recommend adding 1 tsp and only then increasing to taste. Alternatively, you could add a few drops of rose extract.
  • Alcohol: for boozy watermelon jello shots, you could use vodka, tequila, or rum. Just note that you’ll need to add extra agar-agar to make up for the excess liquid. Use around ½ tsp agar powder for ½-3/4 cup alcohol (otherwise, the watermelon jello slices won’t be stiff enough). If you want vegan watermelon jello, make sure your alcohol is vegan!
 
Check the blog post for more helpful tips!
Course: Dessert, Snack
Cuisine: American
Freezer friendly: No
Shelf life: 3-4 Days

Nutrition

Calories: 24kcal, Carbohydrates: 6g, Protein: 1g, Fat: 1g, Saturated Fat: 1g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 1g, Sodium: 1mg, Potassium: 91mg, Fiber: 1g, Sugar: 5g, Vitamin A: 432IU, Vitamin C: 6mg, Calcium: 8mg, Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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