Introduction: Homemade Dippin' Dots

About: I helped start Instructables, previously worked in biotech and academic research labs, and have a degree in biology from MIT. Currently head of Product helping young startups at Alchemist Accelerator, previous…

Dippin' dots are fun to eat, and making the ice cream of the future is actually pretty easy! Use this super-simple tutorial, and you can be eating dippin' dots like a cool space-age kid in no time flat.

What are dippin' dots? They're tiny balls of ice cream (or the frozen treat of your choice), individually flash-frozen in liquid nitrogen. You can mix the balls in different ratios to make other flavors, the equivalent of "swirling" the flavors together in a soft-serve cone. It's silly, but a lot of fun.

I teamed up with sherrycayheyhey to make dippin' dots in a variety of flavors for the 2012 SF Ice Cream & Hot Sauce Takedown. We made a bunch of fun things, including frozen mixed drinks, but the crowd-pleasing favorite was cherry coke: a mix of coke dippin' dots and maraschino cherry juice dippin' dots. I'm using that flavor combo as the example in this tutorial, but feel free to use your imagination and test more bases and combinations. Special thanks to audreyobscura for the amazing photography.

Remember, it's SCIENCE!

Step 1: Tools and Ingredients

maraschino cherry syrup
other liquids-to-be-frozen of your choice (juice, ice cream base, etc - you can even mix in booze)

liquid nitrogen (usually in a dewar or other insulated container)
2 metal bowls
metal spoon
wire strainer
disposable plastic container (bowl, cup, etc)
needle, nail, knife, or other small hole punch (size depends on viscosity of liquid you're using)
insulated gloves or oven mitts

Step 2: How to Get Liquid Nitrogen

The hardest part of this project is likely to be acquiring liquid nitrogen.

First, you'll need to buy or borrow a dewar, aka a double-walled container to store liquid nitrogen. You can buy them new or used, or borrow one from a friend if you're well-connected. Dewars aren't cheap, but they are a specialized tool that works well.

Next, you'll need a source of liquid nitrogen.

  • We buy ours from Airgas or Praxair, large companies who seem to have offices all over. Check for a gas distributor near you. Note that you can also rent large (~100L) dewars - it's cheap rental per day, but generally requires a large deposit. The nitrogen itself is pretty cheap - depending on quantity, you'll pay between $1-3 USD/liter.
  • Most university chemistry, physics, and biology labs will have access to liquid nitrogen. If you know someone who works at one of these, they can probably snag you a couple of liters to make dippin' dots. They buy it in bulk, so it's almost certainly under $1/liter. Buy them a beer or a fancy coffee in return, and you're even.

Step 3: Liquid Nitrogen Safety

Warning: liquid nitrogen is COLD!

No, really cold. Whatever you're thinking of, it's likely much colder than that. It's a frigid -196C or -320F, so much colder than anything you're likely to have come into contact with before. This includes dry ice, which sublimes at a relatively balmy -78.5C or -109F.

This means your standard procedures for dealing with cold items won't quite work when dealing with LN2. To make sure your brain intuitively responds with the right behavior, try thinking of liquid nitrogen as, instead, extremely HOT.

Summary: handle LN2 as if you were dealing with boiling water or hot oil, and you'll likely get it about right.

This means:

  • Cold things are cold.
  • Things that touch cold things are ALSO cold.
  • Don't touch LN2 with your bare skin - it will burn if left there for very long. It's standardly used to freeze off warts. That said, due to the Leidenfrost effect you won't suffer damage from a bit skittering over you - but still, best practice is to avoid touching LN2 directly.
  • Don't let LN2 get trapped against or near your skin.
    • Specifically watch out for absorbent materials (some oven mitts are absorbent!) and pockets, hoods, boots, shoes, gloves, or other clothing that could catch spilled LN2 and trap it against your skin. Even with several layers between you and the LN2, it's still cold enough to do damage.
    • Especially beware of gloves! While they can protect your hands, it's easy to get a drip of LN2 inside and trapped against your hands long enough to burn while you try to rip them off.
  • Pour away from you. This one should be obvious.
  • Everything touching the LN2 will be very cold, often dangerously so. If you're not sure, check before grabbing that spoon or bowl.
  • Never put LN2 in your mouth. Beware that large frozen spheres may have LN2 trapped inside - crush or pop these bubbles before attempting to ingest them.
  • Even without trapped LN2, dippin dots will start off cold enough to burn your mouth. Allow them to come up to a sensible temperature before eating - test in your hands instead of your mouth.
  • Remember the kid in Christmas Story who stuck his tongue to the flagpole? Don't be that kid. And if you do stick your fingers or tongue to something, pour warm water over the stuck skin to remove it, never pull away.
  • Don't be dumb. Again, pretend it's hot oil and behave appropriately.

Step 4: Prep Tools & Stage

Take your plastic container, and poke a number of tiny little pinholes in the bottom. Start small and test - you can always make them bigger.

Test your holes by dumping in a bit of your liquid and bouncing the container over a bowl. You should get discrete drops of liquid, not a drizzle or pour. A thicker, more viscous liquid will require bigger holes, while a thinner less viscous liquid will drip out nicely with smaller holes. Adjust as necessary.

Stage all of your bowls, strainers, spoons, and cups - you don't want to be frantically grabbing at things while juggling ultra-cooled liquids!

Pour at least a ~1cm deep puddle of liquid nitrogen into your big bowl, and making sure your strainers and spoons are right nearby. Place a towel or pad of paper towels on the other side so you have a place to set down your (sticky) plastic container between uses.

Step 5: Dribble and Freeze!

Pour a bit of liquid into your plastic container, and jiggle it over the liquid nitrogen so individual drops drip into the liquid nitrogen.

A water-based liquid will freeze quickly, so you can jiggle (and freeze) quickly. Stir the liquid nitrogen bath with a long spoon, and poke at the frozen balls to make sure they're not sticking to the bottom of the bowl, or to each other. Note that alcohol can take much longer to freeze - the higher % alcohol by volume, the longer you have to wait between drips to avoid drops clumping together and ruining your perfect dippin' dotness.

If you want to be slow and fancy, you can use a syringe to get more perfectly-sized drips - but it takes far too long, I'd rather have irregularly-sized ice cream blobs and get to eat them sooner.

Step 6: Decant Your Dippin' Dots

You can either scoop or pour your dippin' dots out of the nitrogen.

To pour, arrange your strainers in a second bowl, and slowly pour everything (dots and LN2) through the strainer. You may have to poke at the dots a bit to ensure they're all dislodged from the bottom of the bowl before pouring.

To scoop, use a long wood or metal spoon, and drain any remaining LN2. The strainers may still be good for this. Most slotted spoons are probably not fine enough to strain your dots.

Step 7: Store Your Dots

Pour your dots into a freezer-safe container, such as a metal bowl or tupperware, and store over LN2, and/or in the freezer. (Note that alcoholic dots probably melt in the freezer, so keep them over LN2 until ready to use.)

Don't let them melt before eating, else you'll have to re-drip your dots.

Step 8: Serve and Store

Pour your dots into a shot glass or other small glass container that shows off your dots. Layer to mix flavors, and look awesome!

Remember, safety first:

If you just pulled them out of liquid nitrogen, let your dots sit at room temperature for a bit. Test them against the skin of your hands, and then once that doesn't burn test a piece in your mouth before serving to others. The dots will be at a good eating temperature for quite a while, but keep an eye out and pop them in the freezer or back into LN2 before they melt.

If you've been storing the dots in the freezer, they should be good to eat immediately, but will have a slightly shorter lag time before they start to melt and need to be re-frozen.

Have fun! These are great kid-party treats, and can be amazingly fun and nostalgic for adults. Tried it, have a favorite flavor? Let me know in the comments!

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