the left is a line of flexible-arm cooler cars]

For many years the regular factory machines have been of a size
suitable for roasting two bags of coffee at a time; but roasters of
larger size have recently come into considerable use.

Plants treating from fifty to a hundred and fifty bags per day are the
most common; but the daily capacity runs up to a thousand bags or more.
The minimum cost of equipping a plant is somewhere between five thousand
dollars and ten thousand dollars. The individual machines are of
standard construction; but the arrangement in a particular building,
especially for the larger plants, is worked out with great care and with
numerous special features, so that the goods can be handled from start
to finish with minimum expense for floor space, labor, power, etc.

The practical coffee roaster locates his roasting room in the top floor
of his factory building, where light and ventilation are generally best.
He usually has a large skylight in the roof, directly over the roasting
equipment. In addition to the advantage as regards good light and the
convenient discharge of smoke, steam, and odors, through the roof, the
top-story location makes it possible to send the roasted coffee by
gravity through the various bins which may be needed in connection with
subsequent operations, such as grinding, and for temporary storage
before the final packaging and shipping.

_Wholesale Coffee-Roasting Machinery_

The indispensable coffee operations are roasting and cooling; and in
practically all United States plants the cooling is followed by
"stoning". This is an air-suction operation that effects, aided by
gravity, the removal of any stones or other hard material that would
damage the grinding mill. The best commercial cleaning and grading of
the green coffee has usually left in every bag a few small stones. These
can be got rid of better after the coffee is roasted; because it is then
not only lighter, but more bulky.

[Illustration: MILLING-MACHINE CONNECTIONS FOR A TWO-ROASTER PLANT]

Besides these three operations of roasting, cooling, and stoning, the
plant may have machinery for treating the coffee both before it is
roasted and after it leaves the stoner.

[Illustration: A SIXTEEN-CYLINDER COAL ROASTING PLANT IN A NEW YORK
FACTORY

This is a view of the roasting room of B. Fischer & Co. and shows a
battery of Burns coal roasters]

Treatment of the green coffee in roasting establishments is o