Knox Gelatine is a colorless, odorless, tasteless protein-based substance used as a gelling agent in foods. Knox gelatin is unflavored and sugar-free and therefore will not give off any scent when mixed with water. Other brands of gelatin contain sugar and artificial flavors or colors. Knox gelatin's versatility makes it the choice of ballistics labs at the FBI, which melt and reuse the gel to test wound penetration. You can make a gel at home similar to the ballistic gel made in professional laboratories by following a basic recipe.
Pour cold water into the bowl. Use 2 qt. of water for 8 oz. of Knox gelatin or a gallon of water for 1 lb. of Knox gelatin.
Mix in the Knox gelatin powder into the water all at once using a wooden spoon. Stir the powder in carefully and moisten all of it without adding too much air to form a consistency of thick grits.
Place the bowl with the Knox gel mixture into a refrigerator so it can cool and hydrate for about two hours. This is known as blooming.
Remove the bowl from the refrigerator and set on the stove over a pan. Heat the gel to a temperature at or below 130 degrees F until the gel mixture melts. Stir carefully to get as little air as possible trapped in the gelatin. Use a candy thermometer to check the temperature of the gel.
Mix in the food coloring to create a colorful gel. Add as much as you like to create a customized color or mix more than one food coloring for a mixed color. Keep on stirring carefully until color is distributed evenly throughout the gel.
Spray the insides of plastic containers with non-stick cooking spray to imitate the silicone-coated molds professionals use for storing the gel.
Pour the gel into the containers and close the containers by placing the lids on them tightly. Chill gel in the refrigerator for about 36 hours so it sets.
Remove containers with gel from refrigerator and store in room temperature. Cut the gel blocks using a knife if desired. This gel can be remelted and remolded if desired.