How to Make a Gurgling Kettle

Any witch needs a gurgling kettle, right? See more pictures of Halloween candy.
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Halloween is one of those times of year when people tend to go all-out. At any Halloween party supply store, you can fill your cart with things like full-sized skeletons, dismembered limbs, fake blood, plastic rats and bugs, monster heads and spooky black lights. To lend an even creepier element to your d├ęcor, you can buy a gurgling witch's kettle or cauldron -- a black kettle that bubbles out smoke or fog. It's a pretty cool prop, but it can run you $100.

Fear not, though. You can make your own witch's cauldron at home for much less money. Here's how.


First, buy a kettle. Unless you're going for complete authenticity, the kettle doesn't need to be cast iron. Just pick up a large plastic cauldron at a Halloween supply store, or even use a large cooking pot, if you have one on hand. It should be big enough to hold several gallons of water, half-full.

You'll also need dry ice, which is how you get the gurgling smoke effect. Dry ice is actually frozen carbon dioxide. It's able to turn from a solid to a gas without going through a liquid stage, which is why it's called "dry." Some grocery stores sell dry ice, but you may have to call around to find a supplier. Pick up your dry ice as close as possible to the time you want to use it. Ten to 15 pounds (4.5 to 6.8 kilograms) should be enough for your cauldron, and the ice costs a dollar or so per pound. Bring the dry ice home in a Styrofoam cooler, and keep it there. Don't put it in the freezer -- dry ice will actually cause your freezer's thermostat to stop working!

Before we continue, you should know a few things about dry ice:

  • Do not handle dry ice with your bare hands. It will burn your skin.
  • Handle dry ice with tongs or gloves.
  • Never put it in your mouth.
  • Don't store dry ice in an airtight container. (The Styrofoam cooler is fine.)
  • Store dry ice in a well-ventilated area.

While your dry ice is safe in its cooler, prepare your cauldron. Fill it about halfway with hot water. You need hot water to get the maximum effect. To make a real "witches brew," add spices to the hot water (cayenne pepper, patchouli) to give it a "magical" smell. You could add some food coloring, too. To make real bubbles, put in a few squirts of dishwashing liquid.

Next, break up the dry ice with a hammer. Using tongs or gloves, place the ice into the cauldron a few pieces at a time. The cauldron will slowly start gurgling and smoking, and the soap will start bubbling over the sides. You'll see the most fog and smoke from the cauldron for the first 10 minutes or so. However, it will continue to gurgle and bubble for quite some time. As the water cools down over the course of the evening, you can add more hot water and dry ice.

Remember that the area around your kettle will end up damp and possibly slippery from the bubbles. Exercise safety precautions.

William Shakespeare said it best: "Double, double toil and trouble; Fire burn, and cauldron bubble."


Lots More Information

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  • "Dry Ice Information." 2005. (July 23, 2009)
  • Gray, Theodore and Wallich, Paul. "Scare Tactics." Popular Science. Sept. 26, 2006. (July 23, 2009)
  • "Special Effects." 2005. (July 23, 2009)
  • "Superstitions." 2008. (July 23, 2009)