_General Notes._--In California the dipping of raisins in solutions of
lye is yet in its very infancy, and I do not think that in the whole
State over ten tons of lye-dipped raisins have been placed on the market
yearly. But undoubtedly this process is destined to become of
considerable importance, especially in localities where the drying of
the first crop is accomplished with difficulty in the open air. The
first and also most important condition in producing superior dipped
raisins is that the grapes should be absolutely ripe. Unripe grapes will
not produce any good raisins when dipped, but will turn reddish and
otherwise become inferior.
_Dipping Process._--A good location for dipping raisins is by the side
of an irrigation ditch, provided the water in the latter can be depended
upon to flow constantly while the operation of dipping lasts. If not,
the water must be procured by pumping or by means of pipes from
reservoirs or water-works. Flowing water is of great importance in
producing good dipped raisins, and is required for the perfect washing
of the grapes. For this purpose, if no ditch is available, a large
trough may be used to advantage, and so arranged that the water in it
can be kept changing through a continuous flow. The following is a cheap
and efficient arrangement for dipping in actual use in one of the
largest raisin vineyards, and can be recommended on account of its
cheapness and easy working: On one side of the trough is a stationary
iron kettle with a fireplace underneath. By the trough is also placed an
upright post, about five feet high, and on this balanced a horizontal
beam with a double motion. It can be raised and lowered at either end,
or swung to the left or right with ease. On one end of the beam is a
hook on which to hang the grape bucket. On the other side of the trough
is a rough assorting table. Two or more buckets are needed. These
buckets are common galvanized-iron buckets, perforated thickly with
holes, the latter not large enough to let any loose grapes through. In
the kettle is kept constantly boiling a solution of water and potash.
Soda is not suitable. The very best potash should be used in the
proportion of about one pound to twelve gallons of water. The ripe
grapes are now brought to the table and emptied in the buckets. A bucket
is then hung on the beam, the latter swung and the bucket for a second
lowered first in the pure water and then in the boiling potash; but it
is immediately withdrawn and immersed in the water-trough. When rinsed
for a few seconds, the grapes are taken out and spread on common raisin
trays. If the weather is warm, the trays are stacked one on top of the
other, and the grapes thus prepared are dried in the shade.
The rinsing of the fruit before drying is of great importance, and by
far not sufficiently understood. In Valencia the finest raisins are
treated that way and thoroughly rinsed before being dipped in the lye.
But nowhere in Spain are the grapes rinsed in water afterwards, and it
is yet an undecided question if this rinsing improves or injures the
raisins. It is certain that the washing cleanses the berries, as the
water in the kettle is sometimes dark and dirty; but if it is an
advantage to deprive the berries of the lye which more or less sticks to
them is very doubtful. It is well known here that lye-dipped raisins are
apt to mold if the rains set in while the drying lasts, while we are
told that in Spain the dipped raisins do not spoil even if subjected to
several showers of rain. From this it will seem as if rinsing after
dipping is not necessary or perhaps even injurious, but that, on the
contrary, rinsing before dipping is of the utmost importance. It may be
possible that the lye which adheres to the grapes will, in a great
measure, prevent them from molding.
In Spain no olive oil is used for mixing in the lye, and it is not
likely that the oil process will come in vogue in California until it is
fully demonstrated that it not only greatly improves the grapes, but
that it also enables the grower to realize a correspondingly better
price for his raisins. Those who care to experiment with it cannot do
better than to follow the practice as it is used in Smyrna, for a full
account of which we beg to refer to the article under that heading. We
might here only point out that the oil-dipped raisins of Smyrna bring
many times the price of the lye-dipped raisins of Valencia. The
arrangement of dipping, kettles, etc., may, of course, be greatly
varied. Steam may be used for heating the lye and the rinsing water, if
it is desired to keep the latter hot, and regular trays might be used to
hold the grapes, instead of the buckets referred to above. Every grower
will no doubt vary these appliances to suit his own fancy, and improve
upon the methods of others. As an example of the devices used by another
grower, we here reproduce the following from an essay on bleaching
raisin grapes, compiled by the chief viticultural officer, and
especially referring to the system used by Mr. Byron Jackson: “Mr.
Jackson places the grapes on a tray made with a frame of iron, which is
covered with wire gauze with a quarter-inch mesh. The frame projects
upwards on the sides to prevent the fruit floating off while in the dip,
and is made to receive, as a cover, the wooden tray on which the fruit
goes to the dryer. When dipped and rinsed, the wooden tray is placed
over the dipping tray, and two men transfer the fruit by turning over
the two.”
The length of time required for dipping can only be ascertained by
experience, and must differ with the strength of the lye, with the heat
of the solution, and with the thickness of the skin of the grapes. Thus
in different localities the strength of the lye and the length of
immersion must always be different, and may even differ from year to
year. When properly dipped, the skin of the grapes must show some very
minute cracks, similar to cracks in glass which has been heated and
suddenly immersed in or sprinkled with ice-cold water. Deep cracks are
not desirable, as they will cause the juice of the pulp to leak out,
after which the raisins will sugar. In Valencia the grapes used for
dipping are the various varieties of Muscats, while in Smyrna both
Muscats and Sultanas are used. Corinths are never dipped, as they dry
readily and make superior raisins without this process.
_Drying and Curing._--After the grapes are dipped, they must be
immediately dried either in the sun, or in sun and shade alternately, or
entirely in the shade. According to the circumstances attending the
drying of the grapes, the color of the raisins becomes more or less red
or yellow, transparent or opaque. The most perfect amber color is
attained in the shade, while in the sun the color rapidly changes to
reddish, a less desirable color in dipped raisins. The more favorable is
the weather for drying, the choicer will be the raisins, and the better
their color. If the sun is very warm and the chances are otherwise
favorable for drying, the trays should be exposed to the sun only long
enough to have their dip thoroughly evaporated, and for this purpose one
day in the sun may suffice. After this the stacking of the trays is
advisable, and only occasionally may the trays be spread if the drying
does not proceed rapidly enough. Such shade-dried dipped raisins will
assume a beautiful amber-yellow color, and bring several cents more than
those exposed to very warm sun. If, however, the weather is not very
warm, the grapes must be dried in the sun, and the grower has then to be
satisfied with the color that nature will give to his raisins. Dipped
raisins do not necessarily require turning, as they generally dry well
anyhow in from four to six days in fair weather. For this class of
raisins dryers are very useful to help finish the drying. Such dryers
must be almost air-tight, as sandstorms would invariably spoil the
raisins, which, on account of their stickiness, are almost impossible to
afterwards cleanse. Dipped raisins should always be dried on their
trays, and on special drying grounds, which should be so constructed
that no sand can blow on them, or at least so arranged that in case of
rain the sand from the ground will not be splashed over the trays. In
California we have at present no such drying-floors, but it will pay any
one who intends dipping his grapes to construct them either of bricks,
bituminous rock or lumber.
_Stemming, Grading and Packing._--Dipped raisins should be stemmed when
well dried, and then graded in two grades. The proper receptacles for
them are either sacks lined with paper, or twenty-pound boxes, in which
they may be packed without fancy paper, or in the same way as prunes or
other dried fruit. So far no uniform method of packing such raisins has
been adopted in this State.
As to the usefulness and future of dipped raisins, not much can be said
at present. Our importations of Valencia raisins, which are mostly
dipped, are considerable, and as long as this class of cooking raisins
is in demand, there is no good reason why we should not compete and
endeavor to supply the demand. We can produce them as well as Spain can,
and the only reason why we have not competed with Spain so far is that
sun-dried raisins are so readily produced here, that it has not been to
our advantage to produce anything else. There are, however, many places
in our State which will grow Muscatel grapes of good quality, but with
too thick skins to make them proper for sun-dried raisins. For all such
localities the dipping process is to be recommended, as it will enable
the growers to produce marketable raisins, and to profitably supply the
demand for this variety of raisins now imported to this country from
abroad. In localities with early and copious fall rains, the dipping
process will enable the growers to finish quickly before the rains set
in. California dipped second-crop Muscatels and Sultanas have brought as
high as seven cents per pound wholesale.