This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
This is occasionally required on the dispensing counter. Prepare as follows: Take well-prepared malt, grind or bruise it in a mortar. Upon one pound of the powdered malt, contained in a vessel, pour one pint of cold water, and macerate for five hours. Then add four pints of water heated to about 30 °C. (86° F.), and digest for an hour at a temperature not exceeding 55° C. (131° F.). Strain the mixture with strong expression. Finally, by means of a water-bath or vacuum apparatus, at a temperature not exceeding 55° C. (131° F.), evaporate the strained liquid rapidly to the consistence of thick honey. Keep the product in well-closed vessels in a cool place.
. It is by all means of the greatest importance that the temperature should never exceed 65° C. (149° F.), and it is safer, for the preservation of the diastase, to keep it at or below 55° C. (131° F.) until the starch of the malt has been converted into glucose and dextrine. It is absolutely necessary, when preparing malt extract, to have an acurate thermometer, and ascertain exactly the temperature. The rapid evaporation of the infusion does not act injuriously upon diastase.
The concentrated extract of malt is a brown-yellow or light amber-colored semi-liquid, having a slight peculiar odor, and a sweet mucilaginous taste. It dissolves in water in all proportions, the liquid being nearly transparent. An admixture of alcohol produces a milky turbidity, after a short time becoming clear, separating a floculent precipitate.
Good extract of malt contains, besides water, maltose, dextrine, albumen and salts. The commercial extract is frequently mixed with glycerine, syrup, etc., some a merely glucose, and again others consist of a stronger or weaker beer.
Professor Lloyd proposes to macerate four parts of ground malt with a mixture of one part of alcohol and four parts of water, percolating, until three parts of percolate are obtained. It is a thin yellow or brownish liquid, containing the malt sugar and diastase, the latter being destroyed on the application of heat.
This is made after the P. G. by dissolving two parts of pyrophosphate of iron in three parts of water, and incorporating the solution with ninety-five parts of extract of malt. Hager recommends the use of three parts of saccharated iron rubbed up with seven of glycerine, and ninety of extract of malt.
Incorporate some of the extract of hops (page 698) with the malt, which will make another variation.
Saccharated pepsin incorporated with malt extract is of medicinal value in case of dyspepsia, and may be dispensed at the soda-counter. A proper dose of pepsin consists of about ten grains.
A good method of dispensing malt extracts is to put a small quantity of the extract in the tumbler, and draw on the soda water. They are not adapted to prepare bottled beverages, as the diluted malt extract would ferment; however, an enterprising bottler may be inclined to make something out of it for a family trade, especially in the dull season.