A choice flavoring obtained from a climbing orchid,
Vanilla fragrans, a native of tropical American
forests. The vanilla plant belongs to the orchid family
and is indigenous to southeastern Mexico, where it
was used by the Aztecs to flavor their cocoa. In 1510
vagnuila first appeared in Spain. Its fruits are pods
called vanilla beans (see illus.). These are picked at
the proper time before they have fully matured.
Vanillin (4-hydroxy-3-methoxybenzaldehyde) is
the principal component of vanilla, although other
components contribute to the distinctive flavor of
the extract compared to synthetic vanilla. When they
are harvested, the beans contain no free vanillin; it
develops during the curing period from glucosides
that break down during the fermentation and sweating
of the beans. The sweating process consists of alternately
drying the beans in sunlight and bunching
them so that they heat and ferment. Sweating boxes
are used in Mexico, whereas the shorter Madagascar
method starts out by wilting green pods in hot
water and uses blankets on which the beans can first
be spread out and later rolled up for the enzymatic
reactions and fermentation to take place. Further curing
and dehydration occur in a warehouse. Periods
of 4 weeks to 4 months may be required to develop
the proper flavor and reduce the moisture content
of the beans sufficiently to prevent molding. Beans
can be artificially dried in ovens, but frequently an
inferior-quality product results. See FERMENTATION;
FOOD ENGINEERING.
After curing, the pods are sorted into grades based
on quality. The best cured beans are 8–10 in. (20–
25 cm) long, with drawn-out ends and curved bases.
They are soapy or waxy to the touch, dark brown,
and coated with fine crystals of vanillin, termed frost.
Vanillin constitutes 1.2–3.5% of the bean, but other
compounds contribute also to the aroma. In addition
to the flavoring materials, vanilla beans contain
fat, wax, sugar, gum, resin, and tannin. Vanilla
is used in cookery, confectionery, and beverages.
Vanilla extract, most used, is prepared by extracting
the crushed beans with alcohol. A synthetic vanillin
is made from eugenol occurring in clove oil, but the
natural product is preferred. Several plants have been
used as substitutes for true vanilla but these are of
little value. See ORCHIDALES; SPICE AND FLAVORING.
Perry D. Strausbaugh; Earl L. Core
The principal types of commercially used vanilla
beans are the Mexican, Bourbon [Bourbon comes
mainly from Madagascar, but was named after the
island of Bourbon (now Island of R´eunion) in the
Indian Ocean, where the French started the cultivation
of vanilla], South American, Javan, and
Tahitian.
Vanilla extract is prepared from vanilla beans with
or without one or more of the following added: sugar,
dextrose, glycerol. Vanilla extract contains the soluble
matters from not less than 3.3 oz of vanilla
beans in 1 qt (10 g/100 ml). To be legally called
vanilla extract, 1 U.S. gal (3.785 liters) of vanilla extract
must contain the soluble matter from not less
than 13.35 oz (378.5 g) of vanilla beans. The finished
flavoring should contain at least 35% alcohol
by volume to keep the solubles in solution.
In the alcoholic extraction of the vanilla flavor, the
color of the extract is influenced by the quality of
the beans, the strength of the alcoholic menstruum,
the duration of the extraction, and the presence of
glycerin, which is added to retard evaporation and
to retain the flavor of the extract. Best results are
obtained with three consecutive extractions at room
temperature, each requiring a minimum of 5 days.
The first should have a maximum alcohol content
of 65%; the second, 35%; the third, 15%. To improve
aroma, extracts are aged, using stainless steel or glass
containers.
A standard vanilla extract is equivalent in flavoring
strength, though not in quality, to a 0.7%
vanillin solution. The vanillin content of pure extracts
range from 0.04 to 0.12 oz/qt (0.11 to
0.35 g/100 ml), with the average at about 0.06 oz/qt
(0.19 g/100 ml). Ash content, soluble ash, lead number,
total acidity, and acidity other than vanillin are
among the conventional indices used to detect adulteration.
