Sugar glass is a prop for theater and films that looks like real glass, but it is safer because it is softer and not as sharp. If you have ever seen somebody get thrown through a window or hit over the head with a bottle, you have seen sugar glass. The recipe for sugar glass used in big-budget Hollywood films is a closely-guarded secret, but you can make a low-cost version for your next fake fight.
Oil the mold. Non-stick spray works well, but be sure that the alcohol evaporates before you pour the mixture into the mold or it will boil and leave bubbles in your sugar glass.
Mix the water, sugar, corn syrup and cream of tartar in the saucepan and bring it to a boil.
Place the candy thermometer in the pot so that the bulb is in the liquid.
Let the mixture boil, stirring constantly, until it reaches 300 degrees. This takes about 45 minutes. The mixture will be thick, with most of the water will boil off.
Pour the mixture, when it reaches 300 degrees, very quickly into the oiled mold and let it cool.
Pop the mixture very carefully out of the mold, when it has cooled.
Use the sugar glass soon after you make it, or it will become sticky and won't last long. Keep it out of direct sun and moist areas. Keep the sugar glass wrapped in plastic until you're ready to use it. This recipe can also be used for gingerbread houses or Christmas candy. Add food coloring of your choice as soon the mixture is removed from the heat. If desired, add flavoring such as peppermint or cinnamon oil. Break the glass into small pieces and store in an airtight container. The size of the sugar glass will be only limited by the size of the mold. A large cookie sheet works well for small sheets of glass.
Use a pot holder or kitchen gloves when pouring the mixture into the mold. It will be very hot and can stick to the skin, causing severe burns. Handle the sugar glass with care. Although it's candy, it will still have sharp edges and points.