Okay, so I've seen it done but having never attempted to use dry ice before I'm not really sure how it behaves.
I'm making a cauldron cake and was wanting to have the dry ice effect across the top of the cauldron. I was thinking of an acrylic tube down the center of the cake, through the cake base which would be elevated and I could put the dry ice in a container there. Will the dry ice smoke 'float' up the tube? or will it just swirl around the bottom? Any ideas??
Dry ice is a frozen gas, however when it evaporates it is heavier than air and sinks, it will most likely just pool at the base.
I would cut a depression in the center of the cake for a small cup or bowl and put a bit of warm water and ice in the bowl. The warmer the water the more "smoke" from faster ice melt. The ice will cool off the water pretty rapidly as well. While the effect won't last long, it will be very cool.
Remember: Dry Ice will burn skin so never touch it bare handed. It also keeps better outside the freezer. Just store in a cooler (in a cool location) with a towel over the ice. Depending on how much you get it should last at least 24hrs this way.
Thanks! I didn't realize it was heavier....I'm not sure about putting it at the top as there will be lots of kids at the party and I don't want little fingers trying to touch. Might have to forego it this year
You could experiment with putting a small bit of screen over the opening, I think it would still let the smoke through but keep small fingers out.... However I understand your concern.
I just put in my order for dry ice this morning, picking up Saturday (rubbing hands together gleefully)!!!!