The genus Vanilla belongs to the orchid family and has about 120 species. Fifteen of them form aromatic seed pods which are commonly referred to as vanilla pods. Only three varieties are suitable for commercial use of which the spice vanilla, Vanilla planifolia, is by far the most important. The only slightly branched shoot of the evergreen climbing plant reaches a length of at least ten, usually rather fourteen to fifteen meters. The shoot axis is only about one centimeter thick. The rather short-stalked leaves have an elongated oval shape with a pointed end and grow up to 20 centimeters long. Each leaf has a corresponding aerial root associated with it. The strongly ragrant, yellow-greenish flowers form in the axil of a small bract. They have a life span of only about eight hours - before they wither again. The seed pods of Vanilla planifolia reach a length of 10-25 centimeters, have a diameter of just over one centimeter and are also greenish-yellow before ripening. What is colloquially called "vanilla bean" is not a pod in the botanical sense, but a capsule fruit.
For optimum growth, spiced vanilla requires constantly high temperatures of around 28 degrees Celsius and high humidity of around 80 percent. The first fruits form after three to four years. The seed pods are harvested shortly before ripening, when they are still light green in color. The fruits are slightly poisonous when in constant contact with the skin and can cause allergies.
Originally, the spice vanilla comes from Central America and Mexico. Even the Aztecs are said to have appreciated the aromatic ingredient vanillin. For a very long time, Mexico held the worldwide monopoly on the coveted plant, which was mainly due to the fact that only a certain bee of the genus Melipona, native only to Central America and Mexico, pollinated the plant. It was not until 1837 that this very special reproductive mechanism was deciphered, and five years later a plantation slave managed, more or less by accident, to accomplish pollination manually. This artificial pollination with wooden sticks and/or stalks is still done by workers on many plantations today.
Cultivation is carried out in two ways: on the one hand, trees or other plants are used as supporting plants. This form of cultivation is still mainly practiced by small farmers who use coffee, orange or natural trees as support. The yield here varies greatly from 50-500kg of fruit/ha.
On the other hand, spice vanilla can also be grown in monocultures, either with supporting trees or wooden frames. The decisive factor here is the utilization of space in order to achieve the maximum yield. Suitable support trees are Erythrina sp. and Gliricida sepium, which can support about two spice plants per trunk. Although here the yield can be increased up to 4000kg/ha, the yield decreases after the fifth year due to lack of space of the plants.
Vanilla is propagated almost exclusively by stem cuttings. The plant starts flowering only in the second or third year after planting and then in the dry season (usually March-April), depending on the latitude. About 8-9 months after pollination, the capsule fruits are harvested by hand. Currently, the island of Madagascar supplies about 80 percent of the Planifolia vanilla traded worldwide.
In addition to spice vanilla, the Tahitian vanilla, Vanilla tahitensis which grows in the South Pacific region and has a slightly different, more floral aroma, and the Guadeloupe vanilla, Vanilla pompona, from the West Indies, which is preferred for perfume production, are of economic importance.
To extract the highly aromatic vanilla, the fruit capsules must first be pre-treated in a labor-intensive and time-consuming process known as black blanching. For this purpose, the capsule fruits are blanched only briefly in boiling water and then wrapped in blankets to "sweat" in the sun - before they are later uncovered to dry and acquire their typical brown color. Fermentation follows in airtight containers, which continues until the crystallization of fine glucose threads begins. Usually this happens after about four weeks. Drying and fermentation transform the precursors of the flavoring substance contained in the seed fruit into the actual vanillin.
The finished capsules are classified into three qualities: whole, split or chopped. Just the whole or split capsules are further classified into quality grades: extra, superior, good, medium, ordinary, picadura. The vanillin content, measured by dry weight, varies here from over 2.5% (extra) to under 1.5% (picadura).
To obtain vanilla powder, the whole vanilla beans are further dried and then ground into powder. The fruit must have a minimum residual moisture for the grinding process to prevent the grinder from sticking.
Vanilla extract is mainly used in industrial food production and domestic cuisine. Here it provides the typical vanilla flavor in all kinds of desserts, cakes, pastries, ice cream as well as sauces and glazes. A decisive advantage over the pods is the easier dosing and handling of the powder.
Pure vanilla powder is often made from the inferior capsules. In order to nevertheless obtain sufficient quality, it is essential to pay attention to the vanillin content.
Bourbon vanilla owes its name to its long-time main supplier, the island of Réunion, which is located in the Indian Ocean and was called Ile Bourbon until the French Revolution. Bourbon vanilla is now also cultivated on other Indian Ocean islands (Madagascar, Mauritius, Comoros and the Seychelles).
It is a widespread misconception that products containing natural vanilla, or vanillin from the laboratory, must always have a slightly yellowish color. In the case of foods, the coloration comes either from added food colorants or from the chicken egg yolk that is also contained in the product. The association of light yellow with vanilla is a successful marketing construct based on the appearance of the vanilla flower.