TWO BREWING PLANTS RI. W. BRESSER Schwars Laboratories, Inc., New Y o r k , 4.Y.
Kettle
Mash Tub and Rake
Mashing Figure 1. Queens College Brewery, Oxford
T w o pilot breweries of %-gallonand 5-barrel capacity are described. The smaller plant has proved particularly useful for the evaluation of brewing materials and processes. The larger plant, a moderate-sized replica of a typical commercial brewery, is used for more extensive tests on materials and processes which give indication of promise in the 2-gallon plant. These two plants bridge the gap between analytical laboratory scale and commercial brewing in steps of about 75 to 1.
B
REWING is a n ancient art; its origins are obscured by the
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mist of antiquity. But there is ample evidence that men of education, men of science, have believed that a t least a passing acquaintanceship with the intricacies of the a r t and the properties of the product was a part of the education of man. As an example, the archives of Queens College, Oxford, record the establishment of a brewery and the appointment of a brewer in 1340, the year of the foundation of the college itself ( I ) . Three views of this brewery, which is still in working order, are shown in Figure 1. The college has not drifted away from the brewery in the past 6 centuries. Actually, universities and other scientific institutions have worked closely with the brewing industry at all times, and numerous advances in the a r t have resulted from this liaison. Research in brewing is continuous, and some of the tools for this work will be described in this paper. The modern brewery has been termed a beer factory by some practitioners of the art, because relatively recent changes in equipment and method have enabled a single plant t o produce over 4,000,000 barrels of beer (over 120,000,000 gallons) in a single year, and the scientific approach t o brewing and packaging
has resulted in the transformation of the brewery t o a modern industrialized food plant. As part of this change, the size of the equipment has increased, so that 10,000 t o 25,000 gallons are produced in a single brew. Yet the brewer is beset with a multiplicity of variations in the agricultural materials he uses. Some crops require major changes in processing, and any single batch received from a supplier may bring minor alterations, which force the brewer away from his goal of perfect product uniformity. Several large breweries in this country have installed pilot plants to enable their brewers t o gain experience in dealing with new materials and new methods on a small soale before they risk thousands of dollars for materials and labor in commercial brews. Incidentally, such pilot plants are fairly common in Europe. These plants are designed t o enable the operators t o reproduce the beer made in full scale production. However, the vast majority of breweries, and of the processors of brewing materials, do not have such facilities. Schwarz Laboratories has had a 5-barrel pilot plant brewery for over 50 years; it has recently been enlarged and modernized. I n addition, a new 2-gallon pilot plant, particularly designed for preliminary evaluation of materials and processes and for basic research, has been installed. Both plants have been planned t o give flexibility of operation, so that any normal brewing process or product, and some unusual ones, can be reproduced and evaluated. TWO-GALLON BREWERY
The 2-gallon brewery, which provides facilities for simultaneous production of four brews, is set up in a single room with a floor area of about 250 square feet. The general layout is shown in Figure 2, and the brewing table (almost equivalent t o the brewhouse of a commercial plant) is illustrated by Figure 3.
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I-HOT WATER HEATER AND TANK 5-SINK 2.DESK 6 UTLITY TABLE 3BREWING TABLE 7- STORAGE REFRIGERATOR 8 -FERMENTATION REFRIGERATOR +WORK BENCH 9-STORAGE CABINETS
-
Figure 2.
Floor Plan of Two-Gallon Brewery
The provision for four concurrent brews enables one to test, for example, two different processes in duplicate, and to obtain some index of both intraprocess and interprocess differences with minimum labor and XTithout time lag
Figure 3.
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Brewhouse Equipment. The basic unit, around which the eutire plant is designed, is a standard 9-quart stainless steel bainmarie shown in Figure 4 inserted in a special Glas-Col heating mantle. There are t,wo heating circuits in each mantle, one coutrollable by an autotransforiner and the other by a line switch. These stainless steel pots are used for preparation of both malt arid adjunct mashes; t,he belt-driven mash agitators are shown in place in Figure 3 and are pictured in greater detail in Figure 4. A close-up of the brewing table (Figure 4) gives a better view of the recording thermometers, controls, and of a lauter tub in positiorP to drain wort, into a bain-marie, used as a kettle for boiling the wort. The lauter tub has an internal diameter of 4.75 inches, and t,he jacket permits circulation of water a t any desired temperature. This feature eliminates the hazard of falling mash temperatures during the runoff of the wort, and it enables the use of the same units to cool the wort. The lauter tubs have removable false bottoms, either stainless wire cloth in holding rings or conventional slot,tcd bronac. In usual practicc, the spent hops w e removed from the \yurt prior t o cooling. The hops may be separated in a feF 1ninute.Y with a stainless steel collander, or if slow separation is wanted, the lautering unit, with stainless wire cloth in place, is employed to reproduce the action of an old-style hop jack. When the lauter tub is utilized as a wort cooler, it may be fitted with a distributing ring and employed as an open cooler; on the other hand, it may be used as a batch cooler. Equipment is also available for effecting the wort cooling in B closed cooler, which fabricated in two sections. Each section is merely a coil of 0.25-inch stainless t'ubing. The first stage is cooled by cit,y tvater, and the sccoriti section is immersed i n an ice bat,h.
Brewing Table. Two-Gallon Brewery
Mash Agitator
Brewing Table
TABLE I. COMPARATIVE DATA-ALL-MALTA.LE BRDWS 2-Gallon Brewery Brewerv Kettle-filling rate, gal./sq. ft./hr: Yield, malt basis, TO Analysis of ales Acidity, % Etein, % Reducing sugar, '% Apparent extract, Plato Extract of original wort. O Plato
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December 1949
6.73" 73.6
5-Barrel Brewery
6.85a
73.2
0.16 4.29 0.59 1.04
4.38
2.50
2.60
0.18
0.59
1.1G
Usual Range, Commercial, Practice
6-15 64-74 0.16-0.20 4.20-4.65 0.48-0.64 0.7-1.4 2.0-3 .O
12.7
12.8
11.5-13.0
65.0
64.5
60-68
9.8 3.5
Variable
dildly aromatic, pure, hop flavor slightly more pronounced than 2-gallon brews, pleasant ale charactercomparable to commercial ales Data for 2-gallon and 5-barrel plants were obtained on parallel brews, employing identical raw materials and water treatment. N o data are available on commercial brews wlth the same materials. To date, correlations between commercial brews and those of the two pilot plants have usually involved evaluation of specific phases of brewing prooes8. Brews i n 2-gallon 0 Difficulty in runoff experienced in both pilot plants. unit bad bo be mashed up; brew in 5-barrel plant gave trouble, but i t was possible to avoid mashing up b y resorting t o very slow lautering rate.
Brewery Cellars. After cooling, the wort is pitched with brewers' yeast and fermented under controlled conditions. Bains-marie are used as open fermenters and Firestone 2-gallon stainless steel sirup tanks serve as closed fermenters (Figure 5 ) . The fermentations are conducted in an 8-cubic foot refrigerator fitted with special thermostatic controls and a recording thermometer. The controls balance a resistance heater against the cooling unit of the refrigerator and maintain any selected temperature between 40' and 120' F., within 1". Thus, a group of fermentations may be carried through any desired temperature cycle by resetting the controls twice daily, or the fermentations may be conducted a t a single temperature (3). The actual beer temperature follows the ambient temperature in the refrigerator very closely. After the fermentation is complete (in 5 to 10 days, depending on cycle desired), the fermenters are transferred to the 25-cubic foot storage refrigerator, Figure 6. This refrigerator, designed and manufactured to specifications by Koch Refrigerators, holds any selected temperature between 26' and 45 O F. within 1 Here the beer temperature is usually reduced to 32 O F. within 24 hours, and the suspended yeast settles out within the same period. The beer is decanted from the yeast into a Firestone tank, now functioning as a storage tank. The finishing operations, after a period of cold storage for maturation of the beer, are conducted along conventional lines. Various items of ordinary laboratory or small commercial equipment are used in these operations. For example, a nickel alloy and glass pipe-line sirup strainer functions admirably as a diatomaceous earth filter; an Eastern stainless steel centrifugal O.
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pump handles liquid transfers; carbonation is accomplished with the aid of either a Selas filter candle (2 X 0.625 inch, Style FP-52) or by using a glass aspirator pump as a carbonating a r m during a transfer; final filtrations use a n Ertel filter (Model 11); and the carbonated beer is filled into bottles with a stainless steel choke coil ( g ) . The applications of the basic equipment in the 2-gallon brewery to the brewing process are summarized in Figure 7, which illustrates the repeated utilization of the two major functional units, the holding vessel (bain-rnarie), and the strainer (the lauter tub). General Observations. T o date, 38 brews have been made in the 2-gallon brewery. It has been found possible t o produce highly palatable beers and ales with the same degree of control as prevails in good commercial pract,ice. Data on filtration rates, yield, performance of materials, and influence of operating conditions on the quality and stability of the product h a r e been, a t least thus far, translatable t o large scale brewing. Table I gives some representative d a t a obtained on all-malt ale brevs. It requires approximately 10 to 20 man hours of applied labor per brew when several are made a t the same time, depending on the purpose of the test and the particular procedure employed. This time is exclusive of any purely analytical work required.
I
Figure 5.
Firestone Tank
FIVE-BARREL BREWERY
The 2-gallon brewery utilizes, in large measure, standard equipment which is functionally useful for brewing; to the eye, it presents a n unconventional view of brewing equipment. However, t h e 5-barrel plant shows marked resemblance t o a small commercial brewery, both in appearance and in layout, and almost all of the equipment was especially made. This plant is used also by the United States Brewers' Academy, a wholly owned subsidiary of Schwarz Laboratories, Inc., for instruction in brewing operations. Much of t h e equipment has been donated or loaned to the academy by equipment manufacturers.
PR 0C LS S
EQUIPMENT USED
Figure 7.
CQUIPMENT USLD
Equipment Utilization, Two-Gallon Brewery
The 5-barrel brewery is installed in a 3-story brick building approximately 25 X 37 feet; the arrangement of equipment is shown in Figure 8. Raw Materials Handling. The malt and cereal used for brewing are elevated from the first floor t o either the mill or t o hoppers on t h e roof by a pneumatic system. T h e mill is a conventional two-roller unit with a capacity of approximately 250 pounds of malt per hour. Brewing Vessels. The cereal cooker is a coated, dished-bottom iron tank, with a n underdriven agitator. It has a gross capacity of
Figure 6. Storage Refrigerator for Two-Gallon Brewery
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FIRST FLOOR P L A N IA-REFRIGERATION EQUIPNIENT IB-AIR COMPRESSOR IC-BEER STORAGE TANKS ID-RACKER
2 2'-6"
SECOND FLOOR PLAN 2 A - FERMENTING TANKS
WASH ROOM
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about 150 gallons and is heated by direct steam. The old-style copper mash tub is 48 inches inside diameter and 24 inches deep; mixing is effected by overdriven rakes rotating a t 25 r.p.m. (Figure 10). The new-style combination mash-lauter tub has an inside diameter of 38 inches and a depth of 32 inches. This tub has rakes on one arm of the mashing machine and knives on t h e other; the machine has a two-speed drive (approximately 1/3 a n d 15 r.p.m.) with variable speed in each range. The combination mash-lauter is made of copper and bronze and has a glass observation panel. Both mash tubs are heated by direct steam and both have slotted bronze false bottoms. The brew kettle is completely fabricated from Type 304 stainless steel and is cylindrical with dished bottom. It has both a percolator @nda steam jacket for heating. The capacity of the kettle is ample for a brew of 155 gallons (5 barrels) of hot wort. The brewhouse piping is copper, with standard solder fittings. In general, 1-inch tubing is used for wort and water lines, and 1.5inch is employed for mash transfer lines, When the kettle boiling is completed, the wort is dropped in a %inch line through the enclosed basket-type hop strainer to ~k Monel hot wort tank (Figure 9). The latter has a special baffle and a swing-arm drawoff to minimize carry-over of sediment (trub) when emptying. The hot wort piping is arranged so that the wort may be recirculated if desired. The wort may be cooled either over an open copper Morton cooler or through a closed stainless steel Paraflow plate cooler (Figure 11). The coolers have both a water and a brine (40% propylene glycol) section. Cooling capacity is ample for handling a full brew in 45 to 60 minutes. The complete brewhouse cycle requires approximately 8 hours from the start of malt grinding to the completion of cooling. This time varies in accordance with the procedure followed. With a normal mashing schedule, the grain depth in the lauter tub is about 15 inches and the wort may be run to the kettle a t the rate of about 1 gallon per minute. Fermenting Cellar. The fermenting cellar (Figures 8 and 11) has nine tanks; several are aluminum, several wooden, and two are nickel alloy-clad steel. These tanks have a working capacity of approximately 135 gallons (freeboard of 20 to 25% is required to allow for heads). Cellar air temperatures are maintained by a brine-cooled diffuser, and brine headers permit attachment of attemperator coils in each tank for cooling back as the fermentation approaches completion.
THIRD FLOOR PLAN 3 E - C E R E A L COOKER 3F-BREW K E T T L E 3G-PLATE : T Y P E W O R T COOLER 3 H - B A U D ! :LOT COOLER 31-MALT ,,YI,LL. 431 8
3 A - H O T WATER TANK 1 ~ 3 8 - C O N T R O LBOARD 3C-MASH T U B 3 0 - M A S H 8 LAUTER T U B
I
n
t L
L
-
36'-6"
0
0
.:N,
' . Figure 8. Floor Plans of Five-Barrel Plant
Figure 9.
Hop Strainer and Hot Wort Tank, Five-Barrel Plant
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Figure 10. Brewhouse, Five-Barrel Plant
Morton Cooler
Paraflow Cooler
Fermentation Tanks
Figure 11. Coolers and Fermentation Cellar in Fire-Barrel Plant
December 1949
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Figitre
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12. S t o r a g e and Finishing Cellar, Five-Barrel P l a n t
Storage and Finishing Cellar. Thc storage cellar, which ib held at 32" t o 34" F. by brine-cooled air diffmers, is somewhat larger than the fermenter room. Figure 12, a picture of the storage area, shows most of the equipment in this cellar. There are twelve tanks; most of these are glass-lined, but mveral have a baked phenolic lining. Each holds one brew. This area is also used for filtration, carbonation, and othei Enishing operations. There is a stainled8 steel diatomaceous earth filter, with 5 square feet of filter area, and a small pulp filter and pulp cake press. Transfers are made through 1.5-inch brewers' hose, using either a rotary pump or a cent,rifugal carbonating pump Package filling is performed with a one-arm racker for kegs or a small hand-operated bottle filler Bottled beer is pasteurized in normal fashion. GENERAL COMiM ENT i
The 5-barrel plant is a moderate-sized replica of a typical commercial brewery. Although the 2-gallon plant, has been constructed on the lines of purely functional design, the equipment of the &barrel plant is, in general, a scaled-down reproduction of normal brewing equipment. Indeed, in some cases the machinery is actually the smallest unit of the item in commercial production The labor requirement for operation of the 5-barrel plant is appreciahly higher than that of the 2-gallon brewery. For normal brewing procedures, approximately 80 man hours of applied time are required for production of a single brew, exclusive of analytical work Since nor mal brewing equipment may commonly be sized for production of 300 t o 400 barrel brews, it is apparent that the two pilot plants bridge the gap betwecn analytical laboratory scale and commercial brewing in steps of about 75 to 1 This ratio is higher than usual for pilot plant work in chemical industry, but the relatively higher standardization In brewing procedures permits such high ratios without introducing appreciable difficulties in transferring from one t o the othcr
The 2-gallon b t e N ery has dernorist rated i t b utilitj 111 the e\ aluation of brewing materials and processes I t is particularly well suited to the preliminary investigation of malt from new barley crops and varieties, of n w hops and brewing adjuncts, and for determining the influenre of procedural variations on the product Each brew yields about a dozen 12-ounce bottles of finirhed beer, after withdrawal of samples during processing This quantity ie sufficient for rather complete analytical a o r k on the finished, bottled beer. The &barrel plant serves for more extensive tests on the materials or processes which give clear indication of promise in the 2-gallon brewery, prior to commercial oprraticlnq ACKNOWLEDGMENT
The facilities which have been described in this papel are the result of contributions by many members of the i t aff of Scha Hrz Laboratories over an extended period. LITERATURE CITEI)
(1) Hind, H.L.,"Brewing Science aild I-'r.aot,ic.e." V d 1, New York. John Wiley I% Sons, Ino., 1938. (2) Roberts, M., Laufer, S., and Stewart, E. 11..Proc. .4m.S o c . Brewi n g Chemists, 1947,SS. (3) Trolle,"R.,Wallerstpin Loha. ( ' n r t i r i i i i n . ~ . , 22, 226 ( 1 9 4 4 ) .
Correction. In the article on "Catalytic and Thernml Cracfriug of Pure Hydrocarbons" (Greensfelder, Voge, and Good, INI). ENG.CHEM.,41, 2573 (1949), P, was incorrectly printed instead of T on page 2578, second column, third and fourth paragraphs; page 2579, first column, fourth line from bottom, page 2581, second column, sixth line from bottom.
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