Icing (food) desired colour. Sprinkles, colouring mist, edible ink designs, or other decorations are often used on top of icing. The simplest icing is a glacé icing, containing powdered sugar and water. This can be flavoured and coloured as desired, for example, by using lemon juice in place of the water. More complicated icings can be made by beating fat into powdered sugar (as in buttercream), by melting fat and sugar together, by using egg whites (as in royal icing), and by adding other ingredients such as glycerin (as in fondant). Some icings can be made from combinations of sugar and cream
Continuous foam separation of gas into the bottom of the liquid column. The amount of gas flow into the apparatus is measured and maintained through a flow meter. As the foam rises and becomes drained of the liquid, it gets diverted into a separate container to collect the foamate. The height of the foam column is dependent on the application. The diverted foam is liquefied by collapsing the foam bubbles. This can usually be achieved by mechanical means or by lowering the pressure in the foamate collecting vessel. Foam separators for different types of applications use the basic set up shown in the