Have a blast at your next cocktail party by serving drinks topped with explosive hydrogen foam!

WARNING: Playing with explosive gases is very dangerous. You probably shouldn't do it. Especially if alcohol is also involved. The follow instructions describe exactly how to go about making this fun and exciting party drink garnish using cheap household objects purely as a theoretical exercise. It would be downright foolhardy to actually make and serve any cocktails covered in this tasty, lemon-scented, non-toxic foam, no matter how awesome they would appear or how popular they would make you*. I hope we have an understanding.

How does this all work?

It's all very simple: We'll use egg whites to make a light froth, just like when making meringues. This froth, however, won't be full of air bubbles. Instead, it will be full of a 2:1 mixture of hydrogen and oxygen gas. As I'm sure you know, hydrogen can get a little over-excited when it's around oxygen, needing little provocation to explode in a clean-burning ball of fury, producing heat, light and water (2 H₂ + O₂ → 2 H₂O). In the context of our beverage foam, this explosion will produce a bang, a flash, a splash and an ever-so-slightly diluted drink.

Unless you happen to have a tank of hydrogen sitting around at home, you'll need to make your own. The easiest way to do this is by passing an electric current through water, splitting the water molecules into hydrogen and oxygen (2 H₂O → 2 H₂ + O₂). This requires little more than a plastic bottle, some tubing, two pencil leads and a DC power supply.

I spent a long time experimenting with different methods to collect a reservoir full of hydrogen and then whip it into a drink. After building and testing a system of nested and partially submerged interlocking cocktail shakers, I eventually came to the conclusion that the best way to get a good large-bubbled foam is just to let the gas flow directly from its source (i.e. water) into the foam without any additional whisking, whipping, beating or shaking. This method is extremely straightforward, but only lets you produce a small amount of explosive foam at a time. Given how explosive hydrogen is, that's probably for the best.

This sounds complicated. How long will it take?

It's really not complicated at all. You could set this up in less than an hour. You shouldn't, because it's dangerous. But if you do, you should wear safety goggles and have a fire extinguisher to hand. Let's get cracking!

*Very awesome and very popular.

Step 1: Getting Electricity Into Water

First of all, you'll need to choose a DC power supply. I used an old laptop power brick with a 20V 2A DC output.

You'll also need to find a pair of suitable electrodes to conduct the current into the water. Ideally these should have a non-reactive surface such as graphite. Or platinum, if you're feeling fancy. I scraped the copper coating off a pair of graphite welding electrodes to produce two inanimate carbon rods. A few pencil leads bundled together would also do the trick.

Wrap a wire around the end of each electrode and connect them to the positive and negative terminals of your power supply.

Step 2: Bottling It

Poke a pair of holes into the base of a tall plastic bottle. The holes should be on opposite sides of the base so that the electrodes do not touch each other and create a short circuit. Hot glue the electrodes to the inside of the bottle, keeping any exposed metal wiring on the outside of the bottle so it doesn't get wet (better yet - cover the exposed wiring up with heat shrink tubing).

Use what will seem like an excessive amount of hot glue to completely seal the holes in the bottle, leaving the wires trailing out. You can never have too much hot glue.

Step 3: Your Shiny New Reactor

You should have something that looks a little bit like this, although perhaps more stable and with neater wiring.

Step 4: The Outflow Pipe

Now you need to a way to channel the gases from the bottle into your foam. In a typical hydrolysis set-up, you would try to collect gas from the anode and the cathode into two separate containers. Here, however, you want to collect a mixture of the two gases (hydrogen and oxygen), so you can use a single tube to collect all the gas produced from the water.

Drill a hole through the bottle's lid, insert some flexible plastic tubing and go crazy with the hot glue again.

You're almost ready to test your equipment! If you fill your bottle with pure water, you'll find that it doesn't conduct electricity all that well. Add several tablespoons of bicarbonate of soda to help carry electric charge through the water. You could also use table salt, but it carries the risk of producing small amounts of chlorine gas.

Fill the bottle with water, screw the lid on tightly and check that you don't have any leaks. Now try hooking it up to your power source and submerging the free end of the plastic tube in a cup of soapy water. You should soon see bubbles forming. If you touch a match to these bubbles (keeping the flame well away from the sealed bottle of flammable gas!), they should explode delightfully.

Step 5: Bubble Mix

Now that you have a source of explosive gas, you need something to blow it into. Egg whites are excellent at holding bubbles at room temperature, and the addition of a little acid increases their stability. Combine half a teaspoon of lemon juice with three egg whites and whisk them together with a fork. Make sure you're using a clean, soap-free bowl or jug and don't let any yolk into your mix.

Step 6: Foam Party

Clean any soap from your plastic tubing, make sure the tube is full of air* and submerge the free end in your lemony egg whites. If you have a fat separator jug, it makes an excellent tube holder. If not, just hold the tube in place by hand or by tape.

Turn on your power supply and get bubbly!

Just to drive the point home: If you're actually doing this, please be very careful. Don't use any vessels that can shatter. Keep the hydrogen/oxygen mixture away from any flames, heat sources or electrical appliances. Even static sparks from clothing could potentially ignite these gases. Make them in small amounts and make sure you know where they are. Cover any squishy parts of yourself you consider worth protecting.

*You want an air gap to make sure the liquid contents of the bottle do not mix with the egg whites.

Step 7: Serving Suggestions

After a few minutes, you should have collected a sizable clump of bubbles made of egg white and explosive gas. Carefully spoon them from their container onto the surface of your cocktails. Be sure to wipe the spoon clean each time to avoid contaminating your egg whites with your cocktail ingredients.

Step 8: Go Out With a Bang!

You're all set! If any one of these foamy cocktails comes near an open flame, it will fire like a gunshot. Expect a lot of shrieking (hopefully gleeful) and laughter (hopefully maniacal). Enjoy yourself and, as always, let me know how it goes!

General tips:

Make your guests aware that their cocktails contain raw egg whites.
Thinner cocktail glasses will allow you create a deeper foam, making for a more impressive explosion.
If you use a sparkler as a fuse, make sure it hangs down from the glass so that sparks don't hit the foam until the last possible moment.
Serve and ignite the drinks as quickly as possible; the bubbles will bust or deflate if you leave them too long.
Line up a row of explosive cocktails next to each other and light the one on the end for a chain reaction.
Warn your guests what's going on and let them take part in the fun!
Get creative! Experiment! For example, I'd love to see someone try a variant of this as a garnish to food, using a delicious savory xanthan gum gel instead of egg white.