Dry ice can help create a spooky effect at your next Halloween party, but if it isn't properly stored, it will dissipate into a fog before you actually need it to. Dry ice is the frozen form of carbon dioxide, which is why, instead of melting into a liquid when heated, it instead turns into a gas. Because it's so cold (an extra-frigid -109.3°F, to be exact), it sublimates into a gas pretty quickly.
So if you go to the trouble of obtaining dry ice for Halloween, here are a couple tips to follow that will ensure it stays frozen until you need it to billow spooky fog long into the night.
Where to Buy Dry Ice
You can find dry ice at some grocery stores, as well as at ice cream shops (who use it to pack ice cream for shipping). Want to find a retail outlet in your area? Check out this directory and enter your area code:
How Long Does Dry Ice Last?
As a rough rule, five pounds of dry ice will turn from a solid to a gas in 24 hours. It's best to pick up the block of ice just a few hours before your party so it's as frozen as possible when the bash starts.
How to Store and Safely Handle Dry Ice
Once you get it home, do not store inside a freezer. It can damage your freezer and the dry ice will melt quickly since the freezer is so much warmer than the dry ice itself. Instead, store it in a styrofoam or an insulated cooler.
The air inside the cooler will get very cold and slow down the time it takes for the ice to change into a gas. Just be sure to keep the cooler lid slightly ajar, as any dry ice that does turn into a gas can build pressure and cause the lid to pop off.
Wrapping the outside of the dry ice block with a few layers of towels or newspaper is another way to help insulate it. Do this before placing it in a cooler and you've got double the insulation. Pack any empty space in the cooler with towels or newspapers and you've got triple the insulation.
For safety, never let dry ice touch your bare skin! Always handle with gloves or other layers between you and the dry ice.
Read more: 5 Mistakes to Avoid When Using Dry Ice
How to Make Dry Ice Fog!
Once you're ready to get that fog effect going, whether it's in a cauldron or a cocktail, you'll need liquid (usually water, although you can also add it to cocktails) to make it happen. Put the ice in liquid and it will instantly begin to melt into a gas, creating that smoky effect. Warm water creates more fog but it will disappear faster, while cooler water will give you less fog but will last longer.
To keep that fog flowing through the night, just keep adding dry ice to whatever vessel's holding it.
Read more: 3 Pro Tips for Using Dry Ice on Halloween