How to Make Rainbow Jello

Co-authored by wikiHow Staff

Last Updated: June 13, 2021 References Tested

The next time you’re looking for a unique dessert idea, try making your own edible Jello rainbow. While the process is a little time-consuming, it couldn’t be simpler, and the finished product makes a fun, vibrant treat for kids and adults alike. All you have to do is layer different colors of Jello in a baking dish, wait for it all to set, then cut it into squares and watch your guests’ faces light up!

Ingredients

1 box each of red, orange, yellow, green, blue, and purple Jello, 3 oz (85 g)
1–2 cups (8.0–16.0 fl oz) whipped topping (optional)
1 canister plain unflavored gelatin, 16 oz (450 g) (optional)
1-2 cans sweetened condensed milk, 14 fl oz (410 mL) (optional)

Makes one 9 in (23 cm) x 13 in (33 cm) dish of Jello

Part 1

Part 1 of 2:

Preparing the Jello

1
Pick up several boxes of Jello in multiple colors. To make a true rainbow, you’ll need one 3 oz (85 g) box each of red, orange, yellow, green, blue, and purple Jello. However, you’re free to use any colors in whatever order you want.
- You may need to double or triple the amount of Jello you buy and use a larger serving dish if you plan on preparing the dessert for a large crowd. Alternatively, you could scale down the recipe by using only a portion of each box of Jello.
- Rainbow Jello isn’t just a dazzling, delicious dessert—it’s cheap, too. All in all, this recipe shouldn’t cost you more than a few dollars!
Tip: Shop around for fun flavor alternatives for each color. For example, you could use watermelon in place of cherry for your red layer, or pineapple instead of lemon for your yellow layer.
2
Bring a kettle of water to a low boil. Fill your kettle with water and set it on the stove over medium-high heat. While it’s warming up, you can begin unboxing your Jello and gathering the other tools and utensils you’ll be using.^{[1]
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- Jello dissolves and sets best when you use boiling water. However, you can also simply run some hot water from your tap if you don’t feel like waiting for it to boil.
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3
Pour your first color of Jello into a medium-sized mixing bowl. Tear open the packet and shake the powder out into the bottom of the bowl. For a realistic-looking rainbow, you’ll want to start with either red or purple Jello and work your way through the color spectrum from there.^{[2]
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- Make sure the bowl you’re using is roomy enough to hold 2 cups (470 mL) of water along with the Jello powder. This will allow you to mix your ingredients more easily.
4
Add 1 cup (240 mL) of boiling water and stir. Use a spoon or whisk to thoroughly mix the Jello powder into the hot water. As you stir, the powder will dissolve and form a thin, colorful liquid. Check to confirm that there are no bubbles, lumps, or dry pockets in your liquid Jello mix.
- Pour your hot water into a liquid measuring cup before adding it your mixing bowl to make sure you’re using just the right amount.
- Let the hot Jello mixture sit for 3-5 minutes to cool slightly before you continue.^{[3]
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5
Stir in an additional ³⁄₄–1 cup (180–240 mL) of cold water. As you add the cold water, the liquid jello mix will begin to thicken somewhat. Keep stirring the mixture until the second cup of water has been completely incorporated.^{[4]
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- Adding a few ice cubes to your cold water can help the Jello begin setting faster. If you decide to do this, make sure you only use ³⁄₄ cup (180 mL) of water to account for the extra volume.^{[5]
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- Be careful not to incorporate too much water, as this could affect both the flavor and texture of your finished Jello.

Part 2

Part 2 of 2:

Layering and Refrigerating the Jello

1
Transfer the liquid Jello to a casserole dish or walled baking pan. Pour the mixture into the dish slowly to avoid making a mess. This will be the first layer of Jello in your rainbow. For best results, choose a dish that’s around 9 in (23 cm) x 13 in (33 cm), which will allow each layer to come out about ¹⁄₂–1 in (1.3–2.5 cm) thick.^{[6]
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- You could also pour your Jello into drinking glasses, parfait cups, or other small containers to make single-serving treats that don’t require cutting. For this recipe, you'd most likely need 12-15 individual containers.^{[7]
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- Be sure to grab a clean mixing bowl or rinse out the one you used before starting your next flavor to prevent your colors from bleeding into one another.
2
Chill the first layer of Jello in the refrigerator for 25-30 minutes. Slide your casserole dish or baking pan onto one of the upper shelves in your refrigerator where you’ll be able to keep an eye on it. Make sure the shelf you pick out is perfectly flat so the Jello sets in an even layer.^{[8]
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- There’s no need to wait for your Jello to set completely—you just want to leave it in long enough to let it solidify to the point where you can add another layer without the colors mingling.
- If the shelf you use is crooked, your Jello layers may come out thicker on one end than the other, which could throw off the look of your rainbow.
3
Spread whipped topping between the layers if you want to add contrast. If you like, you can spoon 2–3 cups (470–710 mL) of whipped cream onto each layer of Jello after it sets. This will make the colors in your Jello rainbow pop even more and give it an extra sweet, creamy finish.
- For the sake of efficiency, use a tub of whipped topping rather than a spray can, which will take longer to apply evenly.
- Another option is to use plain, unflavored gelatin to make thin white layers that blend better with the Jello. Mix 2 oz (56 g) of gelatin with ¹⁄₂ cup (120 mL) of sweetened condensed milk, ¹⁄₂ cup (120 mL) of hot water, and ¹⁄₂ cup (120 mL) of cold water to make a single layer. Allow each layer to set for 20-30 minutes before adding your next color.^{[9]
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4
Repeat the process with your other Jello colors. Once your first layer has had time to firm up, mix up your next color and pour it into your dish directly on top of your first color or layer of whipped topping. You’ll do this for each color you want to include.^{[10]
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- Don’t forget to alternate with your whipped topping or plain white gelatin if you’ve decided to separate your layers.
- To save time, start mixing your next color of Jello while the previous layer is chilling in the refrigerator.
- You can make as few or as many layers as you like. A full rainbow will have 6 uniform layers, but you could stack up as many as a dozen, as long as you have a big enough dish, or stick to the primary colors (red, yellow, and blue) to keep things simple.
5
Place your rainbow Jello in the refrigerator 2-3 hours to finish setting. After you’ve assembled all of your layers, cover the dish with a piece of plastic wrap and stick it back in the refrigerator one last time. This time, let your Jello sit for the full amount of time specified in the directions.^{[11]
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- You also have the option of simply leaving your finished Jello rainbow in the refrigerator until you’re ready to serve it, since you’ll need to keep it cool anyway.
6
Cut your rainbow Jello into squares before serving it. Use a table knife to carefully slice the single sheet of Jello into precise squares. Aim to make each square the same size so you won’t be left with any thin slivers or oddly-shaped pieces. Enjoy!^{[12]
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- If you’re serving bigger kids and adults, measure your squares to be about 2–3 inches (5.1–7.6 cm) apiece. For smaller children, 1–2 in (2.5–5.1 cm) servings should be plenty.
- Cover your leftover Jello and store it in the refrigerator. It should stay good for a week or longer.^{[13]
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Tip: Use cookie cutters to slice your rainbow Jello into all sorts of fun shapes. Discard the edge pieces, or nibble them on their own when you're done cooking.

Community Q&A

Question

How can I make a slushie?

Qamar

Top Answerer

We have an article on that! Check out how to Make a Slushie.
Question

Can I make my own Jello at home using gelatin crystals?

Qamar

Top Answerer

You can, but it takes longer to make when you're trying to make many different colored Jellos.
Question

Can I put it in the freezer?

Community Answer

You can, but you may end up with a different texture, and the taste is not as good.