After the wort has run off, the solid substances remaining in the mash tub, called grains, are washed out or sparged with water in order to recover as much of the wort contained in them as possible. The grains are then thrown out of the mash tub and sold as cattle feed.

Boiling the Wort in Kettle.- The kettle consists of a pear-shaped copper vessel having a double or jacketed bottom for heating the wort,

AIR VENT

FALSE BOTTOM

VENTILATION PIPE

Hop Jack, Sectional View.

and a vent pipe to roof for conducting off the vapors generated during boiling. The steam outlet of the coil or jacketed bottom is connected to a steam trap which automatically discharges the water condensed in the coil or jacket without materially reducing the pressure of the steam. The wort as soon as it runs clear from the mash tub is collected in the kettle. Steam is turned on in the kettle as soon as the jacketed bottom is covered with wort. This wort, and that continuously running in is then heated to and kept at about 70° R. (190° F.) in order to destroy the action of the diastase and prevent further saccharification in the wort taking place. When the kettle is full or nearly so, steam is further turned on and the wort brought to boiling and boiled for one hour when it should show a good "break." During this boiling the undesirable albuminoids are precipitated in finely divided form, rendering the wort turbid. Upon continued heating these albuminoids unite or lump together and leave the wort between these lumps clear and transparent. This clarification is called the "breaking" of the wort.

Hops are now added, usually about two fifths of the total amount used, after which addition the wort again becomes turbid due to the further precipitation of albuminoids by the tannic acid contained in the hops. After about 40 minutes further boiling the wort should again clarify or show its second break when another two fifths of the hops are added and the wort boiled about 20 minutes. The remaining one fifth of the hops are added and the wort run out of kettle into hop jack immediately. This last quantity of hops is usually of a better quality and is not boiled with the wort as its addition is for the purpose of imparting the hop aroma to the wort. This aroma is due to the hop oil of the hops which is volatile at boiling Vol. 3-20

temperature and would escape, and be rendered useless, if the wort were boiled for any considerable time. All or part of this last hop addition is sometimes placed in the hop jack and the boiling wort run upon it.

Wort in Hop Jack.- The hop jack consists of a round or square iron tank, having a perforated false bottom or strainer and a sparger or sprinkler similar to that of the mash tub. The wort, with the hops, is run into the hop jack and allowed to rest until the hops have settled so as to form a filtering material for the clarification of the wort. As soon as this takes place the wort is pumped to the surface cooler or beer tank located at the top of the cellars. After the wort has all been removed the hops are washed out or sparged with hot water in order to recover as much of the absorbed wort as possible.

Surface Cooler and Beer Tank.- The surface cooler consists of a shallow iron pan of a length and width very large in proportion to its depth so as to give the wort as much surface as possible. Hereby the wort is cooled quite rapidly and aerated.

The beer tank, an iron cylindrical vessel closed at the top, is rapidly supplanting this cooler, since the latter, by the large surface it presents, endangers the wort to infections by impurities or germs always more or less present in the air. As soon as the wort on the surface cooler or in the beer tank cools to about 50° R. (145° F.), the danger of its infection by impurities, bacteria, etc., begins. From this stage until the beer is finally marketed, months later, it requires the daily, almost hourly vigilance of the brewer to keep it pure and free from contamination.

Baudelot Cooler.- This consists of a series of pipes or tubes arranged in vertical tiers, over the outside of which the wort flows, while through them the cooling medium is circulated.

one and a half pounds to the barrel of wort, is usually given, not in its natural state, but first mixed with an equal quantity of wort and thoroughly aerated.

The fermentation now begins. Within 15 to 24 hours white bubbles appear on the surface around the sides of the tub. The wort at this time is covered with a head of thick, lumpy consistency composed largely of albuminoid matter. The whole surface now soon becomes covered with a fine white froth, which soon changes to a frizzled appearance called "kraeusen" stage. The froth head then moves toward the centre, the fermentation becomes more active, the froth head rises higher and becomes darker and the fermentation now passes into the "high kraeusen" stage, generally after about 70 to 80 hours. This stage is maintained for about 48 to 72 hours when the head begins to collapse and deepens in color to the end of the fermentation. The temperature is then gradually reduced by means of cooling attemperators to 3° R. (39° F.) in the next 3 or 4 days. Total duration of fermentation, 10 to 11 days.

Storage of Beer-After the wort is fermented the beer is filled into storage vats (closed at the top) where it is stored at a temperature near the freezing point for about two or three months. During this storage period there is a slight progress of secondary or after fermentation and the yeast settles, and, what is most important in bottle beer that is to be pasteurized, there is a further precipitation of albu

minoids.

Chip Cask Treatment.-When sufficiently matured in storage the beer is run or pumped into the chip casks, so called because in them wooden chips are placed to retain the sediment produced by the finings. In the chip cask, two properties must be imparted to the beer that it did not possess during storage, namely, life or proper amount of carbonic acid gas contents, and brilliancy. Life is given the beer by addition of 8 to 10 per cent of kraeusen, (that is, young beer in the first, or kraeusen stage of fermentation). This when added to the old "flat" storage beer continues to ferment, and, as the casks are closed the gas generated gives life to the whole amount of beer contained.

many compartments or cells filled with filter mass or pulp (a substance similar to blotting paper) through which the beer is forced. The filter mass or pulp can be used again and again, being washed after each use to remove the beer and sediments it collects during filtration. The operation of filtration is as follows: The bunging apparatus is disconnected and air pressure (15 to 20 pounds) is put on the chip cask and the beer thereby forced through the filter.

Racking of Beer.- From the filter the beer passes to the racking bench which must be placed at a higher level in order to cause a back pressure upon the filter and prevent foaming. The racking device consists of two or more faucets of which one is always open so as to give a steady flow of beer.

Carbonating.- Beer is often carbonated. This is the mechanical forcing of carbonic acid gas into the beer by which time, labor, space, and cost of chip casks are saved, besides obtaining a more durable beer.

Pitching and Varnishing.- In order to prevent the beer in wooden vessels from soaking into the wood, they are coated on their insides with an inert or insoluble substance. This is shellac varnish for the large brewery vessels, and pitch for the trade packages.

Bibliography-Relating to American Beers and Malting, and Americanized Methods of Producing English Beers: Robert Wahl and Max Henius, The American Handy-Book of the Brewing, Malting and Auxiliary Trades' (Chicago, 2d ed. 1902); in German, Hantke, 'Handbuch für den amerikanischen Brauer u. Malzer (Milw. 1897).

English Beers and Malting as Practised in England and English Colonies: Walter J. Sykes, Principles and Practice of Brewing (Lond. 1902); Frank Faulkner, Theory and Practice of Modern Brewing (Lond. 1888); Herbert E. Wright, A Handy Book for Brewers' (Lond. 1897); E. R. Southby, Practical Brewing) (Lond. 1889); Frank Thatcher, Brewing and Malting) (Lond. 1898); Lawrence F. Briant, Laboratory Textbook for Brewers) (Lond. 1898); Moritz and Morris, Textbook of the Science of Brewing' (Lond. 1896).

In German Language on German Brewing and Malting: Julius E. Thausing, 'Die Theorie und Praxis der Malzbereitung und Bierfabrikation (5th ed., Leipsic 1898); Eugen Prior, Chemie und Physiologie des Malzes und Bieres (Leipsic 1896); W. Windisch, 'Das Chemische Laboratorium des Brauers' (Ber. 1902); Franz Fasbender, Mechanische Technologie der Bierbrauerei und Malzfabrikation (Vien. 1881-90).

English Translations: Julius E. Thausing, 'Theory and Practice of the Preparation of Malt and the Fabrication of Beer) (Translated from addition of American methods by A. Schwarz the German by William T. Brannt, revised with and H. A. Bauer) (Phila. 1882); Alfred Jörgensen, 'Micro-organisms and Fermentation' (translated from the Danish by Alex. K. Miller and A. E. Lennholm) (Lond. 1900); Emil Chr. Hansen, Practical Studies in Fermentation' (translated from the Danish by Alex. K. Miller) (N. Y. 1896). ROBERT WAHL, Wahl-Henius Institute of Fermentology,