FACTORY PREPARATION OF ROASTED COFFEE Page 14

Making and Filling Containers

As stated before, a large proportion of the coffee sold in the United States is put up into packages, ready for brewing. Such containers are grouped under the name of the material of which they are made; such as tin, fiber, cardboard, paper, wood, and combinations of these materials, such as a fiber can with tin top and bottom. Generally, coffee containers are lined with chemically treated paper or foil to keep in the aroma and flavor, and to keep out moisture and contaminating odors.

As the package business grew in the United States, the machinery manufacturers kept pace; until now there are machines that, in one continuous operation, open up a "flat" paper carton, seal the bottom fold, line the carton with a protecting paper, weigh the coffee as it comes down from an overhead hopper into the carton, fold the top and seal it, and then wrap the whole package in a waxed or paraffined paper, delivering the package ready for shipment without having been touched by a human hand from the first operation to the last. Such a machine can put out fifteen to eighteen thousand packages a day.

Another type of machine automatically manufactures two and three-ply paper cans such as are used widely for cereal packages. It winds the ribbons of heavy paper in a spiral shape, automatically gluing the papers together to make a can that will not permit its contents to leak out. The machine turns out its product in long cylinders, like mailing tubes, which are cut into the desired lengths to make the cans. The paper or tin tops and bottoms are stamped out on a punch press.

Coffee cans are generally filled by hand; that is, the can is placed under the spout of an automatic filling and weighing machine by an operator who slips on the cover when the can is properly filled. The weighing machine has a hopper which lets the coffee down into a device that gauges the correct amount, say a pound or two pounds, and then pours it into the can. The machine weighs the can and its contents, and if they do not show the exact predetermined weight, the device automatically operates to supply the necessary quantity. After weighing, the can is carried on a traveling belt to the labeling machine, where the label is automatically applied and glued. Then the can is put through a drying compartment to make the label stick quickly.

Complete Coffee-Cartoning Outfit in Operation
The girl is feeding the "flats" into an Improved Johnson bottom-sealer. The carton travels to a Scott weigher on the right and thence to the top-sealer on the left

Paper bags are filled much the same way as the tin and the fiber cans. In fact, some packers fill their paper and fiber cartons by the same system; although the tendency among the largest companies is to instal the complete automatic packaging equipment, because of its speed and economy in packaging. Frequently, the weighing machines are used in filling wooden and fiber drums holding twenty-five, fifty, and one hundred pounds of coffee, to be sold in bulk to the retailer.

Three Types of Automatic Coffee-Weighing Machines
Left—Duplex net weigher. Center—Pneumatic cross-weight machine. Right—Scott net weigher

Coffee Additions and Fillers

In all large coffee-consuming countries, coffee additions and fillers have always been used. Large numbers of French, Italian, Dutch, and German consumers insist on having chicory with their coffee, just as do many Southerners in the United States.

The chief commercial reason for using coffee additions and fillers is to keep down the cost of blends. For this purpose, chicory and many kinds of cooked cereals are most generally used; while frequently roasted and ground peas, beans, and other vegetables that will not impair the flavor or aroma of the brew, are employed in foreign countries. Before Parliament passed the Adulterant Act, some British coffee men used as fillers cacao husks, acorns, figs, and lupins, in addition to chicory and the other favorite fillers.

Up to the year 1907, when the United States Food and Drugs Act became effective, chicory and cereal additions were widely used by coffee packers and retailers in this country. With the enforcement of the law requiring the label of a package to state when a filler is employed, the use of additions gradually fell off in most sections.

In botanical description and chemical composition chicory, the most favored addition, has no relationship with coffee. When roasted and ground, it resembles coffee in appearance; but it has an entirely different flavor. However, many coffee-drinkers prefer their beverage when this alien flavor has been added to it.

Treated Coffees and Dry Extracts

The manufacture of prepared, or refined, coffees has become an important branch of the business in the United States and Europe. Prepared coffees can be divided into two general groups: treated coffees, from which the caffein has been removed to some degree; and dry coffee extracts (soluble coffee), which are readily dissolved in a cup of hot or cold water.

To decaffeinate coffee, the most common practise is to make the green beans soft by steaming under pressure, and then to apply benzol or chloroform or alcohol to the softened coffee to dissolve and to extract the caffein. Afterward, the extracting solvents are driven out of the coffee by re-steaming. However, chemists have not yet been able to expel all the caffein in treating coffee commercially, the best efforts resulting in from 0.3 to 0.07 percent remaining. After treatment, the coffee beans are then roasted, packed, and sold like ordinary coffee.

In manufacturing dry coffee extract in the form of a powder that is readily soluble in water, the general method is to extract the drinking properties from ground roasted coffee by means of water, and to evaporate the resulting liquid until only the coffee powder is left. Several methods have been developed and patented to prevent the valuable flavor elements from being evaporated with the water.

A typical dry-coffee-extract-making equipment consists of a battery of percolators, or "leachers", a vacuum evaporating device, and a vacuum drier. The leachers do not differ materially from the ordinary restaurant percolators, a battery usually including from three to seven units, each charge of water going through all the percolations. The resulting heavy liquid then goes to the evaporator to be concentrated into a thick liquor. The evaporator consists of a horizontal cylindrical vapor compartment connected with an inclined cylindrical steam chest in which are numerous tubes, or flues, that occupy almost the whole chest. These tubes are heated by steam. The coffee liquor is passed through the tubes at high speed and thrown with great force against a baffle plate at the opening to the vapor chest. The vapor passes around the baffle plate to a separator. The liquor drops to the lower part of the steam-chest (which is free from tubes), and is ready to be drawn out for the next process, the drying.

At this stage, the extract is a heavily concentrated syrup and is ready to be converted into powder. This is done in the vacuum drier, which consists of a hollow revolving drum surrounded by a tightly sealed cast-iron casing. The drum is heated by steam injected into its interior, and is revolved in a high vacuum. In operation, a coating of coffee liquor is applied automatically, by means of a special device, to the outside of the drum. The liquor is taken by gravity from the reservoir containing the liquid supply and is forced upward by means of a pump into the liquid supply pan, directly under the drum, with sufficient pressure to cause the liquid to adhere to the drum, the excess liquor overflowing from the pan into the reservoir. The coating on the drum is controlled or regulated by a spreader. The heat and the vacuum reduce the extract to a dry powder in less than one revolution of the drum. As the drum completes three-quarters of a turn, a scraper knife removes the coffee powder, which is delivered to a receiver below the drum. Modern vacuum-drum driers have a capacity of from twenty-five to five hundred pounds of dry soluble coffee per hour.

C.W. Trigg and W.A. Hamor were granted a patent in the United States in 1919 on a new process for making an aromatized coffee extract. In this process, the caffeol of the coffee is volatilized and is then brought into contact with an absorbing medium such as is used in the extraction of perfumes. The absorbing medium is then treated with a solvent of the caffeol, and the solution is separated from the petrolatum. Then the coffee solution is concentrated to an extract by evaporation; after which, the extract and the caffeol are combined into a soluble coffee. Five additional patents were granted on this same process in 1921.