Malt Syrup
Malt syrup or malt extract as it is sometimes called is made by selecting high grade barley and allowing the barley to sprout until the sprouts come to a definite length. After they have grown sufficiently the sprout is checked by drying it in a kiln at a definite temperature. The drying must be conducted very carefully so that the enzymes of the barley will not be destroyed.
This prepared malt is now crushed and then put into a liquid and heated to a definite temperature so that the diastase will convert the starch into sugar. There are other enzymes present in the malted barley which play an important rôle while the diastetic activity is going on. After the grain has been sufficiently extracted and the proper conversion has taken place, the liquid containing the constituents of malt is run off and then concentrated to the required consistency in large evaporators. The vacuum is drawn on these evaporators so that the moisture may be removed at a low temperature, so that the enzymatic bodies will not be destroyed. After the syrup has been sufficiently concentrated it is drawn off from the vacuum pans into a clean storage tank, from which it is drawn into barrels and other containers ready for shipment to the baker. The barrels are usually sterilized with live steam and then lined with some substance that will fill the pores of the wood to prevent leaking. The sterilizing is done to destroy any forms of yeast and destructive bacteria that may be present.
The starch of the barley must be soluble before the diastase can convert it into sugar. Sprouting barley contains an enzyme known as cytase which dissolves the cell walls of the starch granule thus converting the raw starch into soluble starch. Proteolytic action also takes place, that is, proteolytic enzymes convert the complex proteins into simpler forms of nitrogeneous matter. The conversion of the protein bodies into simpler forms of nitrogen bodies makes this protein readily available for the yeast cells. The malt extract in which this conversion has taken place will cause the yeast to work more actively than in an extract that doesn't contain much amino acids and amides. In the converting of the soluble starch into sugar the soluble starch is first converted into dextrin, then maltose which is a double sugar and finally into dextrose which is a single sugar. If the conversion has not run long enough we will produce malt extract having high dextrin and low maltose and dextrose content. On the other hand if reaction is allowed to go on for a long period, we will have a low dextrin and maltose content and the dextrose content will be high.
In making the water extraction of the malt very valuable mineral matter is extracted with the other constituents. This mineral matter is very high in phosphates which are essential for yeast. A certain amount of acid is also extracted and produced during the sprouting and conversion of the cereal. The acid reaction of a malt extract is usually due to a lactic.
Lactic acid is essential in fermentation as it accelerates the action of the yeast. Most of the malt extract will run about from 1% to 14% of acid calculated as lactic acid. On the other hand some run from 1.75 to nearly 2% of acid. Malt syrup not only furnishes the required sugars in bread doughs, but also furnishes other valuable substances which are required by the yeast plant which is responsible for the fermentation of doughs. This makes a malt extract essential in modern baking as it furnishes food for the yeast and may be termed a yeast food.