Picture of Kryptonite Candy
The only thing standing between you and your plan to rule the world is superman? Despair no more, just follow this Instructable in order to succeed. Because as you probably know Kryptonite is one of the few things known to hurt or kill superman.

OK, ok I'm exaggerating a bit... In this Instructable I'm going to show you, how to make candy that "glows" under UV light and looks like the fictional mineral from the superman myths.

For some time now, I've been playing around with Fluorescein, which is a dark red powder soluble in water and alcohol. It is commonly used as a fluorescent tracer. Though it is used e.g. in eye drops and biochemical research, it can cause adverse reactions (like nausea or vomiting). Because of this, even though only very small amount are needed I don't think it is safe enough for candy (and it is not easy to get).

Sadly most phosphorescent substances aren't classified as "food grade" (even though they are not toxic). In most "glow under a black light" food Quinine is being used, which is in Tonic Water (in very small quantities). In my opinion for candy it is not suitable thought, because of two major reasons: 1. the bitter taste and more importantly 2. it's melting point is very close to the temperature you will need to make the candy.

So I had to find an other easy to get food grade chemical with a high melting point. My solution: Riboflavin, better known as vitamin B2 or additive E101. It can be found in most vitamin pills, is not toxic and fluorescents yellow under UV light (and even under direct light). The only set back is, that it is destroyed by exposure to light, but in our case it should matter because the process is pretty slow. Btw. that is the reason why you should buy your milk rather in opaque containers and not in glass bottles.

OK enough with the boring science stuff, lets go kill superman ;-)

Becky Stern from MAKE Magazine made an amazing video, on how to make the candy:

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this is very neat you are very creative lol

8bitMisfit1 year ago
ya. thanks for english version. I greatly appreciate it. once again still a great instructable.
Hey! Did you make that uv led kryptonite or bought it?
Hey! Did you make that uv led kryptonite or bought it?
How much oil did you use? drams? drops? oz? or just experimentation?
BrittLiv (author)  fightclub1312 years ago
Just a few drops (about 3-5), the amount I used varied, because everything is going so fast.
tinker2343 years ago
wow do you know where i can get a sour flavor or make
You can add citric acid powder to make things taste more sour.
BrittLiv (author)  craftknowitall2 years ago
Yes, truffleshuffleboi suggested this, too. But adding it might be a bit tricky, because it is not a fluid. If you add it after the cooking process is done, I'm pretty sure it will result in crystallizing the sugar. It could be possible though to solve it in water and cook it with the sugar, but the melting point of citric acid is very close the boiling point of the sugar.
BrittLiv (author)  tinker2343 years ago
I'm afraid you will have to experiment a bit. I don't think that substituting the water with lemon juice will work, because it will probably result in crystallizing the sugar. Maybe you can find an oil with a sour taste.
use your fave OIL based flavor (dont use a water based one or the candy will seize up) you want sour (apple. watermelon. lemon. lime)

then add any of the following
*malic acid
*tartaric acid
*citric acid (easiest to fins at health food/candy/baking stores)

use a 1/4 teaspoonof citric acid and put in during the flavoring stage and mix well.

SOmehow I imagine Kryptonite should be toxicly sour and not toxicly minty...no offense BrittLiv.

I'm definitely gonna make these and I'm gonna make them toxicly sour. thanks for the reipe!
thanks i was thinking toxic sour too
Also found outabout ascorbic acid...look up the intructable on sour gummy candies by sfhandyman....its just vitamin c and trader joe's sells a straight vitamin c powder u could try for the outside combined with a lil sugar to balance the tartness
thansk wow you do your reasearch
jet_ski4 years ago
nice instructable, not sure it counts as cooking though
it sure does, Brittliv did you notice the andy cooking on a hot stove...lol
lmulvehill4 years ago
This is just awesome - My nephews will love this! Thanks for sharing!
I have a friend that is really big into superman, nearing on obsessive. I am So gonna make these for him :p.

You said you can use any type flavoring, correct?
BrittLiv (author)  Keira_Yagami4 years ago
Correct. What are you planning to use? I would love to see some pictures, if you are making it
These sound and look AMAZING! How do they taste though?? Is the flavor only really coming from the mint?
BrittLiv (author)  BrianneMichelle4 years ago
The vitamin B has kind of a weird taste, luckily you don’t need much, so it can be easily masked with any kind of flavor you would like it to have.
philosofree4 years ago
How strong is the flavor from the B2? Or does it have any flavor? I'd like to try adding it to jello mix.
BrittLiv (author)  philosofree4 years ago
It has a flavour, which is hard to describe. You don't need much, though. So you should be able to mask the taste.
All righty then! Thanks for the heads up.
saber11914 years ago
how long does it take to dry and is it hard like rock candy? thanks big smallville fan and am doing for season ending thank
BrittLiv (author)  saber11914 years ago
Hi, it depends a lot on the thickness, I just left them for about an hour. If you want to make sure, that it is hard just wait for a bit longer.
lord_kian4 years ago
HI, i'm concern about using medicine to make candies because even if it's only vitamin this also is a medicine with a recommend doses according to a doctor.
BrittLiv (author)  lord_kian4 years ago
Your concern is right for the vitamins A and D. Vitamin Bs though are water soluble and are eliminated through the kidneys. There can be side effects though, if they are taken in a very high dose for a long time, but this shouldn't be possible with the candy.
Yep, friend of mine almost died from overconsumtion of vitamin B but she's okay now :)
Also, kryptonite isn't entirely fictional anymore ;)
Also, also, nice instructable.
BrittLiv (author)  omnibot4 years ago
Are you sure it was because of vitamin B? Yes, pretty cool, but the fluorine is missing.... thanks!
Well, I'm no doctor but the guy who told me in the ER at the time was. Apparently it overloads the kidneys. But that was a whole yar at the same time.
To continue with what BrittLiv said, consuming Vitamin B in larger-than-dose quantities is no different from consuming Vitamin C - you typically get your %DV of that in a single meal sometimes!
In fact, I would recommend the Vitamin B variety over the tonic water, as quinine has a few side effects as well.
BrittLiv (author)  thalden4 years ago
Thanks for mentioning, I wrote about that but deleted it later because the intro text was getting to long
im trying to do the right now and it all just seems way to easy but it is that easy and im amazzeled
Sara alv4 years ago
Hi! I was just reading this and it's kind of confusing to me to get it completly, I still don't know if there are two ways of doing this the powdering sugar with quartz crystals way and the aluminium foil or if they work together to make the candy... Help please.... I really want to do this!!
BrittLiv (author)  Sara alv4 years ago
Hi, there are two ways of making the mould, you can decide which one you prefer.
Mongpoovian4 years ago
Congratulations on the win! I think this candy project was my favorite. :)
mary candy4 years ago
es sieht sehr lecker aus. ;)
BrittLiv (author)  mary candy4 years ago
Vielen Dank, bei deinem Namen hätte ich gedacht, dass du selber mitmachst... Sehe gerade, dass du Deutsch Lehrerin bist... Da muss ich mich ja anstrengen keine Fehler zu machen ;-)
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