Vanilla is a flavoring derived from orchids of the genus Vanilla, primarily from the Mexican species, Flat-leaved Vanilla (V. planifolia). The word vanilla derives from the Spanish word "vainilla", little pod.[1] Pre-Columbian Mesoamerican peoples cultivated vanilla and Spanish conquistador Hernán Cortés is credited with introducing both vanilla and chocolate to Europe in the 1520s.[2]
Attempts to cultivate the vanilla plant outside Mexico and Central America proved futile because of the symbiotic relationship between the tlilxochitl vine that produced the vanilla orchid and the local species of Melipona bee; it was not until 1837 that Belgian botanist Charles François Antoine Morren discovered this fact and pioneered a method of artificially pollinating the plant. The method proved financially unworkable and was not deployed commercially.[3] In 1841, Edmond Albius, a 12-year-old slave who lived on the French island of Réunion in the Indian Ocean, discovered the plant could be hand-pollinated. Hand-pollination allowed global cultivation of the plant.[4]
There are currently three major cultivars of vanilla grown globally, all of which derive from a species originally found in Mesoamerica, including parts of modern day Mexico.[5] The various subspecies are Vanilla planifolia (syn. V. fragrans), grown on Madagascar, Réunion, and other tropical areas along the Indian Ocean; V. tahitensis, grown in the South Pacific; and V. pompona, found in the West Indies, Central, and South America.[6] The majority of the world's vanilla is the V. planifolia variety, more commonly known as Bourbon vanilla (after the former name of Réunion, Île Bourbon) or Madagascar vanilla, which is produced in Madagascar and neighboring islands in the southwestern Indian Ocean, and in Indonesia.[7][8] Leptotes bicolor is used in the same way in South America.
Vanilla is the second most expensive spice after saffron,[9][10] because growing the vanilla seed pods is labor-intensive.[10] Despite the expense, vanilla is highly valued for its flavor, which author Frederic Rosengarten, Jr. described in The Book of Spices as "pure, spicy, and delicate" and its complex floral aroma depicted as a "peculiar bouquet".[11] As a result, vanilla is widely used in both commercial and domestic baking, perfume manufacture and aromatherapy.
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The Totonac people, who inhabit the Mazatlan Valley on the Gulf Coast of Mexico in the present-day state of Veracruz, were the first to cultivate vanilla. According to Totonac mythology, the tropical orchid was born when Princess Xanat, forbidden by her father from marrying a mortal, fled to the forest with her lover. The lovers were captured and beheaded. Where their blood touched the ground, the vine of the tropical orchid grew.[3]
In the fifteenth century, Aztecs invading from the central highlands of Mexico conquered the Totonacs, and soon developed a taste for the vanilla bean. They named the bean "tlilxochitl", or "black flower", after the mature bean, which shrivels and turns black shortly after it is picked. Subjugated by the Aztecs, the Totonacs paid tribute by sending vanilla beans to the Aztec capital, Tenochtitlan.
Until the mid-19th century, Mexico was the chief producer of vanilla. In 1819, however, French entrepreneurs shipped vanilla beans to the islands of Réunion and Mauritius in hopes of producing vanilla there. After Edmond Albius discovered how to pollinate the flowers quickly by hand, the pods began to thrive. Soon, the tropical orchids were sent from Réunion Island to the Comoros Islands and Madagascar, along with instructions for pollinating them. By 1898, Madagascar, Réunion, and the Comoros Islands produced 200 metric tons of vanilla beans, about 80% of world production. According to the UN Food & Agriculture Organisation, Madagascar is currently responsible for the vast majority of the world's bourbon vanilla production[12] and 58% of the world total vanilla bean production.
The market price of vanilla rose dramatically in the late 1970s after a tropical cyclone ravaged key croplands. Prices remained high through the early 1980s despite the introduction of Indonesian vanilla. In the mid-1980s, the cartel that had controlled vanilla prices and distribution since its creation in 1930 disbanded.[13] Prices dropped 70% over the next few years, to nearly US$20 per kilogram; prices rose sharply again after tropical cyclone Hudah struck Madagascar in April 2000. The cyclone, political instability, and poor weather in the third year drove vanilla prices to an astonishing US$500 per kilogram in 2004, bringing new countries into the vanilla industry. A good crop, coupled with decreased demand caused by the production of imitation vanilla, pushed the market price down to the $40 per kilogram range in the middle of 2005. By 2010, prices were down to US$20/per kilo.
Madagascar (especially the fertile Sava region) accounts for much of the global production of vanilla. Mexico, once the leading producer of natural vanilla, with an annual 500 tons, produced only 10 tons of vanilla in 2006. An estimated 95% of "vanilla" products actually contain artificial vanillin, produced from lignin.[14]
Vanilla was completely unknown in the Old World before Cortez. Spanish explorers arriving on the Gulf Coast of Mexico in the early sixteenth century gave vanilla its current name. Spanish and Portuguese sailors and explorers brought vanilla into Africa and Asia later that century. They called it vainilla, or "little pod". The word vanilla entered the English language in the 1754, when the botanist Philip Miller wrote about the genus in his Gardener’s Dictionary.[15] Vainilla is from the diminutive of vaina, from the Latin vagina (sheath) to describe the way the pod must be split open to expose the seeds.[16]
The main species harvested for vanillin is Vanilla planifolia. Although it is native to Mexico, it is now widely grown throughout the tropics. Madagascar is the world's largest producer. Additional sources include Vanilla pompona and Vanilla tahitiensis (grown in Tahiti and Niue), although the vanillin content of these species is much less than Vanilla planifolia.[17]
Vanilla grows as a vine, climbing up an existing tree (also called a tutor), pole, or other support. It can be grown in a wood (on trees), in a plantation (on trees or poles), or in a "shader", in increasing orders of productivity. Its growth environment is referred to as its terroir, and includes not only the adjacent plants but also the climate, geography, and local geology. Left alone, it will grow as high as possible on the support, with few flowers. Every year, growers fold the higher parts of the plant downward so the plant stays at heights accessible by a standing human. This also greatly stimulates flowering.
The distinctively flavored compounds are found in the fruit, which results from the pollination of the flower. One flower produces one fruit. Vanilla planifolia flowers are hermaphroditic: They carry both male (anther) and female (stigma) organs; however, to avoid self-pollination, a membrane separates those organs. The flowers can be naturally pollinated only by a specific Melipone bee found in Mexico (abeja de monte or mountain bee). This bee provided Mexico with a 300-year-long monopoly on vanilla production, from the time it was first discovered by Europeans and the French first transplanted the vines to their overseas colonies, until a substitute was found for the bees. The vines would grow, but would not fruit outside of Mexico. Growers tried to bring this bee into other growing locales, to no avail. The only way to produce fruits without the bees is artificial pollination. And today, even in Mexico, hand-pollination is used extensively.
In 1836, botanist Charles François Antoine Morren was drinking coffee on a patio in Papantla (in Veracruz, Mexico) and noticed black bees flying around the vanilla flowers next to his table. He watched their actions closely as they would land and work their way under a flap inside the flower, transferring pollen in the process. Within hours, the flowers closed and several days later, Morren noticed vanilla pods beginning to form. Morren immediately began experimenting with hand-pollination. A few years later in 1841, a simple and efficient artificial hand-pollination method was developed by a 12-year-old slave named Edmond Albius on Réunion, a method still used today. Using a beveled sliver of bamboo,[18] an agricultural worker lifts the membrane separating the anther and the stigma, then, using the thumb, transfers the pollinia from the anther to the stigma. The flower, self-pollinated, will then produce a fruit. The vanilla flower lasts about one day, sometimes less, so growers have to inspect their plantations every day for open flowers, a labor-intensive task.
The fruit, a seed capsule, if left on the plant, will ripen and open at the end; as it dries, the phenolic compounds crystallize, giving the beans a diamond-dusted appearance, which the French call givre (hoarfrost). It will then release the distinctive vanilla smell. The fruit contains tiny, flavorless seeds. In dishes prepared with whole natural vanilla, these seeds are recognizable as black specks.
Like other orchids' seeds, vanilla seed will not germinate without the presence of certain mycorrhizal fungi. Instead, growers reproduce the plant by cutting: they remove sections of the vine with six or more leaf nodes, a root opposite each leaf. The two lower leaves are removed, and this area is buried in loose soil at the base of a support. The remaining upper roots will cling to the support, and often grow down into the soil. Growth is rapid under good conditions.
The term French vanilla is often used to designate preparations that have a strong vanilla aroma, contain vanilla grains and may also contain eggs (especially egg yolks). The appellation originates from the French style of making vanilla ice cream with a custard base, using vanilla pods, cream, and egg yolks. (The egg yolks are essential to French vanilla ice cream, as they provide its signature pale yellow color; whereas ordinary vanilla ice cream contains no eggs and, thus, is white.) Inclusion of vanilla varietals from any of the former or current French dependencies noted for their exports may in fact be a part of the flavoring, though it may often be coincidental. Alternatively, French vanilla is taken to refer to a vanilla-custard flavor.[20] Syrup labeled as French vanilla may include custard, caramel or butterscotch flavors in addition to vanilla.
Though there are many compounds present in the extracts of vanilla, the compound vanillin (4-hydroxy-3-methoxybenzaldehyde) is primarily responsible for the characteristic flavor and smell of vanilla. Another minor component of vanilla essential oil is piperonal (heliotropin). Piperonal and other substances affect the odor of natural vanilla. Vanillin was first isolated from vanilla pods by Gobley in 1858.[22] By 1874, it had been obtained from glycosides of pine tree sap, temporarily causing a depression in the natural vanilla industry.
Vanilla essence comes in two forms. Real seedpod extract is an extremely complicated mixture of several hundred different compounds, including acetaldehyde, acetic acid, furan-2-carbaldehyde, hexanoic acid, 4-hydroxybenzaldehyde, 2-methoxy-4-(prop-2-en-1-yl)phenol, methyl 3-phenylprop-2-enoate, and 2-methylpropanoic acid. Synthetic essence, consisting basically of a solution of synthetic vanillin in ethanol, is derived from phenol and is of high purity.[23]
| Country | Production (tonnes) |
% |
|---|---|---|
| Indonesia | 4,362 | 58% |
| Madagascar | 2,830 | 23% |
| China | 1,382 | 9% |
| Mexico | 524 | 2% |
| Tonga | 263 | 2% |
| Turkey | 215 | 1% |
| French Polynesia | 74 | 2% |
| Comoros | 65 | 0.6% |
| Uganda | 48 | 0.5% |
| Malawi | 23 | 0.2% |
| Kenya | 20 | 0.2% |
| Réunion | 10 | 0.09% |
| Guadeloupe | 8 | 0.08% |
| Zimbabwe | 5 | 0.03% |
| Source: UN Food & Agriculture Organization [24] |
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In general, good vanilla will only come from good vines and through careful production methods. Commercial vanilla production can be performed under open field and "greenhouse" operations. Both production systems share the following similarities:
Vanilla grows best in a hot humid climate from sea level to an elevation of 1500 m. The ideal climate has moderate rainfall, 150–300 cm, evenly distributed through 10 months of the year. Optimum temperatures for cultivation are 15–30 °C (59–86 °F) during the day and 15–20 °C (59–68 °F) during the night. Ideal humidity is around 80%, and under normal greenhouse conditions it can be achieved by an evaporative cooler. However, since greenhouse vanilla is grown near the equator and under polymer (HDPE) netting (shading of 50%), this humidity can be achieved by the environment. Most vanilla processing is done in the region within 10 to 20 degrees above and below the equator.
Soils for vanilla cultivation should be loose, with high organic matter content and loamy texture. They must be well drained, and a slight slope helps in this condition. Soil pH has not been well documented, but some researchers have indicated an optimum soil pH of around 5.3.[26] Mulch is very important for proper growth of the vine, and a considerable portion of mulch should be placed in the base of the vine.[27] Fertilization varies with soil conditions, but general recommendations are: 40 to 60g of N, 20 to 30g of P2O5 and 60 to 100g of K2O should be applied to each plant per year besides organic manures like vermicompost, oil cakes, poultry manure and wood ash. Foliar applications are also good for vanilla, and a solution of 1% NPK (17:17:17) can be sprayed on the plant once a month. Vanilla likes a lot of organic matter; therefore 3 to 4 applications of mulch a year are adequate for the plant.
Dissemination of vanilla can be achieved either by stem cutting or by tissue culture. For stem cutting, a progeny garden needs to be established. Recommendations for establishing this garden vary, but in general trenches of 60 cm in width, 45 cm in depth and 60 cm spacing for each plant is necessary. All plants need to grow under 50% shade as well as the rest of the crop. Mulching the trenches with coconut husk and micro irrigation provide ideal micro climate for vegetative growth.[28] Cuttings between 60 and 120 cm should be selected for planting in the field or greenhouse. Cuttings below 60 cm need to be rooted and raised in a separate nursery before planting. Planting material should always come from unflowered portions of the vine. Wilting of the cuttings before planting provides better conditions for root initiation and establishment.[25]
Before planting the cuttings, trees that will support the vine must be planted at least three months before sowing the cuttings. Pits of 30 x 30 x 30 cm are dug 30 cm away from the tree and filled with farm yard manure (FYM or Vermicompost), sand and top soil mixed well. An average of 2000 cuttings can be planted per hectare. One important consideration is that when planting the cuttings from the base 4 leaves should be pruned and the pruned basal point must be pressed into the soil in a way that the 4 nodes are in close contact with the soil, and are placed at a depth of 15 to 20 cm.[27] The top portion of the cutting is tied up to the tree using natural fibers like banana or hemp.
Several methods have been proposed for vanilla tissue culture, but all of them begin from axillary buds of the vanilla vine.[29][30] In vitro multiplication has also been achieved through culture of callus masses, protocorns, root tips and stem nodes.[31] Description of any of these processes can be obtained from the references listed before, but all of them are successful in generation of new vanilla plants that first need to be grown up to a height of at least 30 cm before they can be planted in the field or greenhouse.[25]
In the tropics, the ideal time for planting vanilla is from September to November, when the weather is neither too rainy nor too dry, but this recommendation varies with growing conditions. Cuttings take 1 to 8 weeks to establish roots, and show initial signs of growth from one of the leaf axils. A thick mulch of leaves should be provided immediately after planting as an additional source of organic matter. Three years are required for cuttings to grow enough to produce flowers and subsequent pods. As with most orchids, the blossoms grow along stems branching from the main vine. The buds, growing along the 6 to 10 inch stems, bloom and mature in sequence, each at a different interval.[28]
Flowering normally occurs every spring, and without pollination, the blossom wilts and falls, and no vanilla bean can grow. Each flower must be hand-pollinated within 12 hours of opening. The only insect capable of pollinating the blossom is the Melipona, a bee native only to Mexico. All vanilla grown today is pollinated by hand. A small splinter of wood or a grass stem is used to lift the rostellum or move the flap upward, so that the overhanging anther can be pressed against the stigma and self pollinate the vine. Generally one flower per raceme opens per day, and therefore the raceme may be in flowering for over 20 days. A healthy vine should produce about 50 to 100 beans per year; however growers are careful to pollinate only 5 to 6 flowers from the 20 on each raceme. The first 5 to 6 flowers that open per vine should be pollinated, so that the beans are similar in age. These agronomic practices facilitate harvest and increases bean quality. It takes the fruits 5 to 6 weeks to develop, but it takes around 9 months for the bean to mature. Over-pollination will result in diseased and inferior bean quality.[27] A vine remains productive between 12 and 14 years.
Most diseases come from the uncharacteristic growing conditions of vanilla. Therefore, conditions like excess water, insufficient drainage, heavy mulch, over-pollination and too much shade favor disease development. Vanilla is susceptible to many fungal and viral diseases. Fusarium sp, Sclerotium sp, Phytopthora sp and Colletrotrichum sp cause rots of root, stem, leaf, bean and shoot apex. These diseases can be controlled by spraying Bordeaux mixture (1%), Carbendazim (0.2%) and Copper oxychloride (0.2%).
Biological control of the spread of such diseases can be managed by applying to the soil Trichoderma (0.5 kg per plant in the rhizosphere) and foliar application of Pseudomonads (0.2%). Mosaic virus, leaf curl and Cymbidium mosaic potex virus are the common viral diseases. These diseases are transmitted through the sap; consequently affected plants have to be destroyed. The insect pests of vanilla include beetles and weevils that attack the flower, caterpillars, snakes and slugs that damage the tender parts of shoot, flower buds and immature beans, and grasshoppers that affect cutting shoot tips.[27][28] If organic agriculture is practiced, insecticides are avoided, and mechanical measures are adopted for pest management.[25] Most of these practices are implemented under greenhouse cultivation, since in the field such conditions are very difficult to achieve.
Most artificial vanilla products contain vanillin, which can be produced synthetically from lignin, a natural polymer found in wood. Most synthetic vanillin is a byproduct from the pulp used in papermaking, in which the lignin is broken down using sulfites or sulfates. However, vanillin is only one of 171 identified aromatic components of real vanilla beans.[32]
Leptotes bicolor also belongs to the orchid family and is used as a natural vanilla replacement in Paraguay and southern Brazil.
In the United States, Castoreum, the exudate from the castor sacs of mature beavers, has been approved by the Food and Drug Administration (FDA) as a food additive,[33] often referenced simply as a "natural flavoring" in the product's list of ingredients. It is commonly used in both food and beverages, especially as vanilla and raspberry flavoring.[34] It is also used to flavor some cigarettes and in perfume-making.
The vanilla bean grows quickly on the vine but is not ready for harvest until maturity — approximately ten months. Harvesting vanilla beans is as labor intensive as pollinating the blossoms. Immature dark green pods are not harvested. Pale yellow discoloration that commences at the distal end of the beans is an indication of the maturity of pods. Each bean ripens at its own time, requiring a daily harvest. To ensure the finest flavor from every bean, each individual pod must be picked by hand just as it begins to split on the end. Overmatured beans are likely to split, causing a reduction in market value. Its commercial value is fixed based on the length of the pod. If the bean is more than 15 cm in length, it belongs to first-quality product. If the beans are between 10 and 15 cm long, pods are under the second-quality category, and beans less than 10 cm in length are under the third-quality category. Each of the beans has a considerable amount of seeds inside the pod, which are covered by a dark-red liquid from which the vanilla essence is extracted. Vanilla bean yield depends on the care and management given to the hanging and fruiting vines. Any practice directed to stimulate aerial root production has a direct effect on vine productivity. A five-year-old vine can produce between 1.5 and 3 kg pods, and this production can increase up to 6 kg after a few years. The harvested green beans can be commercialized as such or cured in order to get a better market price.[25][27][28]
Several methods exist in the market for curing vanilla; nevertheless, all of them consist of four basic steps: killing, sweating, slow-drying, and conditioning of the beans.[35][36]
The vegetative tissue of the vanilla pod is killed to stop the vegetative growth of the pods and disrupt the cells and tissue of the beans, which initiates enzymatic reactions responsible for the aroma. The method of killing varies, but may be accomplished by heating in hot water, freezing, or scratching, or killing by heating in an oven or exposing the beans to direct sunlight. The different methods give different profiles of enzymatic activity.[37][38]
Testing has shown that mechanical disruption of bean tissues can cause curing processes,[39] including the degeneration of glucovanillin to vanillin, so the reasoning goes that disrupting the tissues and cells of the bean allow enzymes and enzyme substrates to interact.[40]
Hot-water killing may consist of dipping the pods in hot water (63–65 °C) for three minutes, or at 80 °C for 10 seconds. In scratching killing, beans are scratched along their length.[38] Frozen or quick-frozen beans must be thawed again for the subsequent sweating stage. Tied in bundles, rolled in blankets, beans may be placed in an oven at 60° C for 36 to 48 hours. Exposing beans to sunlight until they turn brown is a method originating in Mexico that was practiced by the Aztecs.[40]
Sweating is a hydrolytic and oxidative process. Traditionally, it consists of keeping beans, for seven to ten days, densely stacked and insulated in woolen or other cloth. This retains a temperature of 45–65 °C and high humidity. Daily exposure to the sun may also be used, or dipping the beans in hot water. The beans are brown and have attained much of the characteristic vanilla flavor and aroma by the end of this process, but still retain a 60-70% moisture content by weight.[40]
Reduction of the beans to 25–30% moisture by weight, to prevent rotting and to lock the aroma in the pods, is always achieved by some exposure of the beans to air, and usually (and traditionally) intermittent shade and sunlight. Beans may be laid out in the sun during the mornings and returned to their boxes in the afternoons, or spread on a wooden rack in a room for three to four weeks, sometimes with periods of sun exposure. Drying is the most problematic of the curing stages; unevenness in the drying process can lead to the loss of vanillin content of some beans by the time the others are cured.[40]
This step is performed by storing the pods for five to six months in closed boxes, where the fragrance develops. The processed beans are sorted, graded, bundled, and wrapped in paraffin paper and preserved for the development of desired bean qualities, especially flavor and aroma. The cured vanilla beans contain an average of 2.5% vanillin.
Once fully cured, the vanilla beans are sorted by quality and graded. Vanilla grades depend mostly on the length of the bean, since there is a correlation between length and vanillin content.[41][42] Some commonly used grades are shown in the table below.
Vanilla extract is normally made from Grade B beans.
| Grade A / Grade I |
15 cm and longer, 100–120 beans per pound | Also called "Gourmet" or "Prime". 30–35% moisture content. |
| Grade B / Grade II |
10–15 cm, 140–160 beans per pound | Also called "Extract beans". 15–25% moisture content. |
| Grade C / Grade III |
10 cm |
There are three main commercial preparations of natural vanilla:
Vanilla flavoring in food may be achieved by adding vanilla extract or by cooking vanilla pods in the liquid preparation. A stronger aroma may be attained if the pods are split in two, exposing more of a pod's surface area to the liquid. In this case, the pods' seeds are mixed into the preparation. Natural vanilla gives a brown or yellow color to preparations, depending on the concentration. Good-quality vanilla has a strong aromatic flavor, but food with small amounts of low-quality vanilla or artificial vanilla-like flavorings are far more common, since true vanilla is much more expensive.
A major use of vanilla is in flavoring ice cream. The most common flavor of ice cream is vanilla, and thus most people consider it to be the "default" flavor. By analogy, the term "vanilla" is sometimes used as a synonym for "plain". Although vanilla is a prized flavoring agent on its own, it is also used to enhance the flavor of other substances, to which its own flavor is often complementary, such as chocolate, custard, caramel, coffee, cakes, and others.
The cosmetics industry uses vanilla to make perfume.
The food industry uses methyl and ethyl vanillin. Ethyl vanillin is more expensive, but has a stronger note. Cook's Illustrated ran several taste tests pitting vanilla against vanillin in baked goods and other applications, and, to the consternation of the magazine editors, tasters could not differentiate the flavor of vanillin from vanilla;[45] however, for the case of vanilla ice cream, natural vanilla won out.[46]
In an in-vitro test, vanilla was able to block quorum sensing in bacteria. This is interesting because in many bacteria quorum sensing signals function as a switch for virulence. The microbes become virulent only when the signals indicate that they have the numbers to resist the host immune system response.[47] The essential oils of vanilla and vanillin are sometimes used in aromatherapy. In old medicinal literature, vanilla is described as an aphrodisiac and a remedy for fevers; these purported uses have never been scientifically proven. It has been shown that vanilla increases levels of catecholamines (including adrenaline), and as such can also be considered mildly addictive.[48]