Chapter 72
In the wet roast method he will spray the coffee, while the cylinder is still revolving, with three to four quarts of water to every 130 pounds of coffee. In the dry method he depends altogether upon his cooling apparatus.
Roasters generally are not in favor of the excessive watering of coffee in and after the roasting process for the purpose of reducing shrinkage.
"Heading" the coffee, or checking the roast before turning it out of the roasting cylinder, is quite another matter and is considered legitimate.
Where coffees are watered in the cylinder at the close of the roast to reduce the shrinkage, it is possible to get back only about four percent of the shrinkage by such treatment and the practise is frowned upon by the best roasters.
Generally speaking, water is turned into the roasting cylinder to quench the roast. The amount varies with the style of machine, whether gas or coal. Usually the water turns to steam, and the result is not an absorption of the water but a momentary checking of the roast with a tendency to swell and to brighten the coffee. This is, comparatively speaking, a "dry roast", but not an absolutely dry roast. It is doubtful if more than one percent of American coffee roasters employ an absolutely "dry" roast--it does not give satisfactory results. The word has been abused for advertising purposes. Of course, a dry roasted coffee is a better article for making a satisfactory beverage than one that has been soaked with water; but the word "dry" must be given a definite meaning, which the trade generally will agree to uphold, if it is to have any real meaning or value to the consumer. Until some standard for roasted coffee shall be established, it is to be feared the term "dry roast" will continue to be used for coffee roasted by almost any other process.
[Ill.u.s.tration: UPPER-STORY VIEW OF A JUBILEE PLANT, SHOWING ROASTER, COOLER, AND STONER EQUIPMENT
The parts under roasting-room floor are shown in the ill.u.s.tration below]
[Ill.u.s.tration: LOWER-STORY VIEW OF THE SAME PLANT FROM ABOUT THE SAME ANGLE
Showing connection from floor hopper to stoner on the left, and suspended bucket-elevator boot with four-bag dump hopper on the right]
[Ill.u.s.tration: COMPLETE GAS COFFEE-PLANT INSTALLATION]
The Bureau of Chemistry held a hearing in 1914 at Was.h.i.+ngton, at which the question of a ruling on watering coffees was discussed. The trade was well represented, but no agreement was reached. It was deemed inadvisable to make a definite rule on the watering of coffee; because the water content can not be controlled, as the bean starts to absorb moisture as soon as it leaves the roaster.
_On Roasting Coffee Efficiently_
A.L. Burns, New York, is well qualified to speak on this subject. He says:
Roasting coffee is not so difficult a matter as is often claimed by operators and "experts" who seek thus to magnify their importance; but it is nevertheless a process about which a great deal may be learned in the school of practical experience. With one of our modern machines anybody with ordinary intelligence and nerve can take off a roast after one trial which
Modern coffee roasting machines provide for easy control of the heat (from coal, c.o.ke, or gas fuel), for constantly mixing the coffee in such a manner that the heat is transmitted uniformly to the entire batch, for carrying away all steam and smoke rapidly, for easy testing of the progress of the roast, and for immediate discharge when desired. The operator's problem therefore is the regulation of the heat and deciding just when the desired roasting has been accomplished.
If all coffees were alike, roasting would soon be almost automatic.
In some plants most of the work is on one uniform grade or blend.
But coffees which vary greatly in moisture-content, in flinty or spongy nature, and in various other characteristics, will puzzle the operator until he establishes a personal acquaintance with them in various combinations in repeated roasting operations. The roasterman therefore must be able to observe closely, to draw sensible conclusions, and to remember what he learns. Roasting coffee is work of a sort which anybody can do, which a few people can do really well, and no one so well but that further improvement is possible.
There is no absolute standard of what the best roasting results are. Some dealers want the coffee beans swelled up to the bursting point, while others would object to so showy a development. Some care nothing at all about appearance as compared with cup value, while others insist on a bright style even at some sacrifice of quality. Business judgment must decide what goods can be sold most profitably.
The loss of coffee in weight in the roasting operation, or shrinkage as it is called, is a matter which offers opportunities for false claims of advantage in roasting processes. Anybody can see that if just as good roasted coffee could be produced with a lessened shrinkage there would be a chance for a decided increase in profits. It is a sort of finding-money proposition which always turns out to be too good to be true. The purpose of roasting coffee is to produce an article entirely different from green coffee, which is accomplished mainly by driving out moisture. If coffee is roasted thoroughly, inside as well as outside, so as to give the greatest roasted coffee value, it must sustain a proper loss in weight which there is no legitimate way to avoid. The amount of shrinkage varies a great deal with the kind of coffee and its age, also with the kind of roasting desired.
Adding a little water to the coffee at the end of the operation has the advantage of checking the roast at the desired point and helping to swell and brighten the coffee, but it is a practice which is sometimes abused by soaking the coffee with water so as to reduce the shrinkage. This is done either dishonestly, to steal coffee which belongs to somebody else, or foolishly; for the heavier coffee has a lessened cup value which more than counterbalances the apparent gain.
[Ill.u.s.tration: BURNS JUBILEE GAS ROASTER]
_A Typical Coal Roaster_
A typical United States coal roaster is shown in the accompanying cut.
It is the latest form of that type of Burns machine which requires a brickwork setting. The picture shows the roaster ready to operate, except for smoke pipe and power connections.
[Ill.u.s.tration: BURNS COAL ROASTER WITH BRICKWORK SETTING]
The front of the machine shown has a cast-iron plate having brackets which support the cylinder front bearing, and double fire doors below for the furnace and the ash pit. The movable part of the roaster is hidden by the front head, a heavy casting which stands still except when moved by hand through a half-turn for feeding and discharging.
The cylinder is driven by gears at the back, revolving constantly at uniform speed. The inside of the cylinder is arranged with reverse-spiral f.l.a.n.g.es which mix the coffee perfectly and make uneven roasting impossible; and they discharge promptly every grain of coffee when the front-head opening is turned to the lower position. The roaster is generally operated with coal fuel, but can be used with gas by installing a suitable burner under the cylinder.
[Ill.u.s.tration: OPEN PERFORATED CYLINDER WITH FLEXIBLE BACK HEAD]
COST CARD FOR ROASTERS
_Showing the value added to the cost of green coffee by roasting_
By A.C. Aborn
BASIS: 16 percent Shrinkage.
3/4 cent a pound for Roasting.
Cost Green, Cost Roasted, Cents per Lb. Cents per Lb.
5 6.85 5-1/8 6.99 5-1/4 7.14 5-3/8 7.29 5-1/2 7.44 5-5/8 7.59 5-3/4 7.74 5-7/8 7.89
6 8.04 6-1/8 8.19 6-1/4 8.33 6-3/8 8.48 6-1/2 8.63 6-5/8 8.78 6-3/4 8.93 6-7/8 9.08
7 9.23 7-1/8 9.37 7-1/4 9.52 7-3/8 9.67 7-1/2 9.82 7-5/8 9.97 7-3/4 10.12 7-7/8 10.27
8 10.42 8-1/8 10.57 8-1/4 10.71 8-3/8 10.86 8-1/2 11.01 8-5/8 11.16 8-3/4 11.31 8-7/8 11.46
9 11.61 9-1/8 11.76 9-1/4 11.90 9-3/8 12.05 9-1/2 12.20 9-5/8 12.35 9-3/4 12.50 9-7/8 12.65
10 12.80 10-1/8 12.95 10-1/4 13.10 10-3/8 13.24 10-1/2 13.39 10-5/8 13.54 10-3/4 13.69 10-7/8 13.84
11 13.99 11-1/8 14.14 11-1/4 14.29 11-3/8 14.43 11-1/2 14.58 11-5/8 14.73 11-3/4 14.88 11-7/8 15.03
12 15.18 12-1/8 15.33 12-1/4 15.48 12-3/8 15.63 12-1/2 15.77 12-5/8 15.92 12-3/4 16.07 12-7/8 16.22
13 16.37 13-1/8 16.52 13-1/4 16.67 13-3/8 16.82 13-1/2 16.97 13-5/8 17.11 13-3/4 17.26 13-7/8 17.41
14 17.56 14-1/8 17.71 14-1/4 17.86 14-3/8 18.01 14-1/2 18.15 14-5/8 18.30 14-3/4 18.45 14-7/8 18.60
15 18.75 15-1/8 18.90 15-1/4 19.05 15-3/8 19.20 15-1/2 19.35 15-5/8 19.49 15-3/4 19.64 15-7/8 19.79
16 19.94 16-1/8 20.09 16-1/4 20.24 16-3/8 20.39 16-1/2 20.54 16-5/8 20.68 16-3/4 20.83 16-7/8 20.98
17 21.13 17-1/8 21.28 17-1/4 21.43 17-3/8 21.58 17-1/2 21.73 17-5/8 21.87 17-3/4 22.02 17-7/8 22.17
18 22.32 18-1/8 22.47 18-1/4 22.62 18-3/8 22.77 18-1/2 22.92 18-5/8 23.07 18-3/4 23.21 18-7/8 23.36
19 23.51 19-1/8 23.66 19-1/4 23.81 19-3/8 23.96 19-1/2 24.11 19-5/8 24.26 19-3/4 24.40 19-7/8 24.55
20 24.70 20-1/8 24.85 20-1/4 25.00 20-3/8 25.15 20-1/2 25.30 20-5/8 25.45 20-3/4 25.60 20-7/8 25.75
21 25.89 21-1/8 26.04 21-1/4 26.19 21-3/8 26.34 21-1/2 26.49 21-5/8 26.64 21-3/4 26.79 21-7/8 26.93