DIY Sugar Cubes Pour about 1/2 cup of sugar into a bowl. Use a teaspoon to pour small amounts of water on the sugar, little by little, and mix until it is a paste-like consistency. Make sure the sugar doesn’t melt during this process. Fill the sugar-water-paste into ice cube trays, about half-way full, and press tight into the mold. Let dry overnight. Carefully remove the sugar cube from the ice cube tray.