ity, which is known as "wine-making
ripeness." This stage of ripeness is determined by means of a
must-scale or saccharometer. The wine-maker squeezes the juice from a
number of bunches of grapes into a receptacle into which he drops the
must-scale, whereupon the sugar-content of the juice is indicated on
the scale, determining whether the proper stage of ripeness has been
reached. Suitable varieties of grapes having been grown, it is
necessary that they be permitted to hang on the vine until the proper
degree of ripeness is developed, after which they are delivered at the
winery as free as possible from injury or decay.

The second stage is the preparation of the grapes for fermentation.
The grapes are weighed on arriving at the winery and are then conveyed
either by hand or more often by a mechanical conveyor to the hopper or
crusher. The ancient method of crushing, which still prevails in some
parts of Europe, was to tramp the grapes with bare feet or wooden
shoes. Tramping has been superseded by mechanical crushers which break
the skin but do not crush the seeds. The best mechanical crushers
consist of two-grooved revolving cylinders. As the grapes pass through
the crusher, they fall into the stemmer, a machine which tears off the
stems, discharging them at one end, while the seeds, skins, pulp and
juice pass through the bottom to the presses usually on the floor
below. There are several types of wine-presses, all of which, however,
are modifications of screw, hydraulic or knuckle-joint power. In large
wineries, the hydraulic press has almost driven out the other two
forms of power and when great quantities of grapes must be handled a
number of hydraulic presses are usually in operation. The grape
pomace is built up into a "cheese" by the use of cloths and racks
variously arranged. The "cheese" is then put under heavy pressure from
which the juice or "must" is quickly extracted.

The third stage is fermentation. The "must" is carried from the press
into open tanks or vats which hold from 500 to 5000 gallons or even
more. The yeast cells which cause fermentation may be introduced
naturally on the skins of the grapes; or in many modern wineries the
"must" is sterilized to rid it of undesirable micro-organisms and a
"starter" of "wine-yeast" is added to start the fermentation. Yeast
organisms attack the sugar and must, breaking it up into alcohol and
carbonic acid gas, the latter passing off as it is formed. When acti