How to Make Glowing Jelly

Here’s a really simple and fun experiment to do at home: make glowing jelly (or jello, American friends)! The method is really easy – you’re just making jelly – but you do need some kind of UV light source to see the effects[1].


It’s a very simple idea: you make jelly but use a 1:1 mixture of plain ol’ water and tonic water (e.g. Canada Dry). Tonic water contains quinine which is naturally fluorescent and so the resultant jelly will glow under a UV light. Here’s what I did:

  1. Boil 100ml of water and mix with the jelly so it all dissolves.
  2. Top up with cold water up to 300ml.
  3. Add 300ml of tonic water.
  4. Mix it up really well and put it in the fridge.

Quinine glows a blue-ish colour under UV light so I used green jelly to maximise the effect. I’m assuming that the jelly acts as a kind of filter to the fluorescence, so using red jelly would probably result in a very poor glowing jelly. And nobody wants that. There was no blue jelly in the shop; not much blue food in general, actually.

Fluorescence occurs in some materials when they absorb high-energy light photons and then re-emit that energy as lower-energy photons. In this case, the quinine is absorbing UV photons and re-emitting them as visible light (UV light is higher-energy than optical light).

Glowing Jelly!

The results were pretty much awesome. You can see our glowing green jelly above. It tasted great too. Lime turned out to be a good flavour to accompany the tonic water, which would normally have a bitter taste. The kids gobbled it up – under the glow of the UV lamp.

Glowing Jelly

This project was really quick and easy and the kids loved it! I think there may be glowing jelly – and maybe other glowing foods – at Halloween this year.


[1] You can buy UV torches and lights at Maplin or Amazon. There are likely other places too, of course 🙂


28 thoughts on “How to Make Glowing Jelly

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  1. Will adding alcohol to the jelly cause the UV effects to lessen? I am wondering if I could add gin or vodka to this recipe, but I want to make sure it will still glow.

    1. Pretty sure you can add some gin, it will still glow more than likely; but I’m not sure. You’ll probably just have to experiment a bit yourself with it.

  2. Do you think it’s possible to make glowing jello shots? maybe replacing the boiling water with the tonic water and 150 ml of alcohol and 150 ml of more tonic water? I may just experiment it myself and let you know the results but it you know then please let me know

    1. You should be fine to add some Vodka – some Vodka is actually fluorescent too!

      Only thing to note: alcohol might mean that you need to get the mixture colder in order to get it to set, but I’m sure with just a little extra alcohol it will be more or less the same as above. Depends how much you want to add 🙂

  3. Hi!!!
    Very interesting recipe. Do you know the wave lenght that the UV has to have? Its enough the one (not carcinogenic) used in discos?

    1. The peak wavelength is 350nm and I’m guessing it should be nicely matching the UV lamps used commonly in clubs 😉

  4. I can confirm, unfortunatly: I’ve try it with red jelly and it doesn’t glow!! You must go green! 😉

  5. Not sure which country you’re in but here in the states you can get blue raspberry jello. Don’t particularly like raspberry myself but it might be worth it to see the result.

  6. Being in the US, I’m not familiar with that brand of “jelly”. Will a 3-oz package of Jell-O work or does it need to be cut down before mixing?

    1. Any jelly or jello will do, so long you use water and tonic water to make it up ( in a 1:1 ratio). The colour matters a little: green and yellow are better than purple or red.

  7. You can make it Blue simply with food coloring. You may also can use gelatin, agar-agar, or gellan gum. the latter two is seaweed extract. Then you need the tonic water, 20 g gelatine, or 10 g agar-agar, perhaps 6 g gellan gum, and a good few drops of food coloring. if anyone need more detail, ask!

  8. Hello from Chicago. My daughter and I made this tonight using Jell-O’s Melon Fusion (green in color) with Tonic Water per recipe. We plan on using Halloween shaped cookie cutters once the gelatin solution solidifies tomorrow. We’re both excited to see how this works out! The Blue Raspberry idea is a good one as it does have an electric blue tint to it…. Next time, right? THANKS!!

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