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Facts about Raising Agents. Raising agents work by incorporating a gas into a mixture. When you heat the gas it expands and then it rises. So the mixture has alight open texture. Raising agents maybe added by mechanical means such as sieving.
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Facts about Raising Agents • Raising agents work by incorporating a gas into a mixture. • When you heat the gas it expands and then it rises. So the mixture has alight open texture. • Raising agents maybe added by mechanical means such as sieving. • Can be included in the ingredients such as yeast and bicarbonate of soda. • Raising agents can be natural and chemical.
Natural raising agents. • The three gases which make products light are • air, • Steam, • carbon dioxide • In most mixtures you use more than one raising agent. • So in a cake it would be self raising flour but air would also be trapped when creaming.
Air • Air is added mechanically to food when you are • Whisking • Sieving • Creaming • Beating • Rubbing in • Rolling and folding
Steam • Steam is a raising agent when a mixture has a high proportion of liquid which is then cooked at a high temperature . • As the water is then turned into steam. Such as • Yorkshire puddings • Choux pastry • Flaky and rough puff pastry.
Carbon Dioxide • Carbon dioxide is used as a raising agent when • A biological raising agent like yeast is used. • Or a chemical raising agent like bicarbonate of soda is used.
Biological Raising agents • Yeast is a micro-organism. • When it reproduces it gives off carbon dioxide gas.
The following conditions are needed for reproduction. • Warmth between (25 and 28C) At low temperatures it slows down and at high temperatures it is killed. • Liquid
The following conditions are needed for reproduction. Food • Sugar added to the mixture or obtained from flour Time • The mixture must be covered and left to rise in a warm place.
Chemical Raising Agents • Chemical raising agents produce carbon dioxide when they are heated with a liquid. • Self raising flour is very convenient as the raising agent is already added. • Bicarbonate of soda produces carbon dioxide and washing soda when heated. The washing soda is hidden by the flavours added to the cakes. • Bicarbonate of soda plus acid, such as soured milk used in scones. The acid prevents the washing soda being made. • Baking powder is a convenient mixture of bicarbonate of soda and an acid.