Technology & MSG

Jun 9th, 2007 by Alex

When I was in college, we made progressive screwdrivers on two occassions. Made with vodka — frozen by liquid nitrogen (LN2) — and orange juice, the drink gets progressively stronger as the vodka melts. The concept is quite simple, easy to execute, and it’s just plain cool. The safety requirements in handling LN2 do make it a novelty for special occassions rather than a staple of every weekend, however. A recent blog entry about LN2 ice cream made me remember all of this, so here’s how to do it.

Major props to STH — a brilliant biochemist — for showing us how to do this without injuring ourselves. He also had a recipe for autoclaving turkey, although I never (unfortunately) got to partake in that. Though I haven’t kept in touch with him, remembering him make these drinks always brings out the mad scientist in me.

Disclaimer

Do not do any of what follows if you aren’t trained in the handling of ultra cold substances. LN2 isn’t meant to be a recreational substance. If you screw up, you stand a good chance injuring yourself or someone else.

Definitely do not do any of what follows if you’ve been drinking.

This should be obvious, but keep safety in mind when transporting and handling LN2. The liquid is extremely cold, can easily cause tissue damage, and can cause asphixia by displacing oxygen in the air. As an example, 1 liter of LN2 becomes approximately 25 cubic feet of gas; make sure the area is vented. To paraphrase Mitch Hedberg, you — in your natural environment — are accustomed to having ample oxygen available… so make sure you don’t deprive yourself of it, especially on your ride home.

Protect exposed skin. Wear non-canvas shoes or leather boots. Wear long sleeves and pants.

Supplies

Get yourself a pair of eye googles or a face shield. LN2 can splash, so eye glasses are not good enough.

Get yourself a pair of mid-arm cryo gloves or make friends with someone who already has a pair. These will probably set you back at least $100, so the latter might be a better idea.

Make arrangements to get a dewar of LN2. I don’t have any specific recommendations about where to obtain it aside from gas supply houses, however any biochemist should be able to tell you where their labs get it (and could probably obtain a few liters if they were so inclined).

You’ll need two three foot lengths of utility rope, like you’d use for a clothesline (if you remember those). Tie the two ends together, then repeat with the other length. You’ll be using the loops to hold the weight of the full icecube tray. To avoid dropping the tray and splashing the LN2, make sure they’re firm.

You’ll need a styrofoam cooler with detachable lid, sufficiently large to lay the icecube tray in the bottom. The smaller the better, so long as it fits the tray with a bit of room around the sides. The larger the cooler the more LN2 you’ll have to use per batch. Fill the cooler with water to insure there are no leaks. Afterwards, dry the cooler completely.

You’ll need a solid surface to work on. A countertop will do nicely, as will the floor.

And last but not least you’ll need orange juice, an icecube tray, a set of tongs, and a bottle of vodka.

The Procedure

You are essentially making ice cubes, except we’re making two substitutions. Vodka for water and LN2 for the freezer. We all know that water freezes at 0°F. Alcohol freezes at -117°F. Dry ice is 109.3°F, clearly not cold enough to freeze alcohol although if you wanted to freeze all of the additives out of your liquor I supposed you could do it that way. LN2 is -320.4°F, more than cold enough to freeze alcohol.

Fit the loops around both ends of an icecube tray.

Fill the tray with vodka, as if you were making ice cubes.

Put on your cryo gloves. Do NOT remove them until later.

Everyone will want to see, but the truth is that all they’ve see is a lot of gas escaping from the cooler. They won’t see much more even if they are closer, so get your guests to move back a few feet. Carefully pour LN2 from the dewar into the cooler until you’ve got two inches (or enough to complete submerge the icecube tray in). Cap the dewar and put aside.

Do not ever submerge your hands into the liquid at the bottom of the cooler! If you drop the ropes, just wait until all the LN2 boils off and retrieve the ropes with the tongs. Better to lose a bit of LN2 than to lose a finger to frostbite.

Use the rope loops to lift the icecube tray without sticking your head over the top of the cooler. Lower it gently into the cooler until it hits bottom, then place the remaining rope loops hanging outside the cooler. Put the top on. You’ll hear the LN2 boiling away and there will be a lot of vapors emitted. The cloudy vapor is condensed moisture from when the nitrogen mixes with the surrounding air; remember that nitrogen is colorless.

Give it a minute or two to work. Get your guests to prepare a few cups of orange juice in the meantime. Mellow in the fact that you’re behaving like a mad scientist.

Still wearing gloves, right? When the boiling dies down, remove the top and place it upside down on your solid surface. Fish the tray out of the cooler using the loops and deposit the tray on the cooler’s top. Move the loops aside and flip the tray over. Give it a few smacks and then use the tongs to deposit 1-2 cubes into each waiting cup.

Secure the cooler and dewar.

Remove your cryo gloves.

Enjoy it…

Sip at your drink. At first it will be entirely orange juice. As the cube melts, the drink mixes itself and will become stronger as time passes. Not a bad way to introduce someone to vodka, really.

Try to avoid the cubes. When immersed in orange juice, a layer of ice and frozen orange juice will instantly form around the cube. This will partially insulate your lips from the cold center, but I’d still avoid the cube. Sucking, chewing on, or swallowing it would be a bad idea and will probably involve a trip to the emergency room. Think frostbite, but internally.

Now who said science couldn’t be fun?

Note: Due to the potentially hazardous nature of this procedure, I only posted the one image. I do have more. If you’re serious about trying this, leave a comment and I’ll send the URL for the rest to your email address.