Vanilla

Vanilla is the second-most expensive spice after saffron, because growing the vanilla seed pods is labor-intensive. Despite the expense, vanilla is highly valued for its flavor. As a result, vanilla is widely used in both commercial and domestic baking, perfume manufacture, and aromatherapy.

The distinctively flavored compounds are found in the fruit, which results from the pollination of the flower. These seed pods are roughly a third of an inch by six inches, and brownish red to black when ripe. Inside of these pods is an oily liquid full of tiny seeds. Harvesting vanilla fruits 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 fruits is an indication of the maturity of pods. Each fruit ripens at its own time, requiring a daily harvest. To ensure the finest flavor from every fruit, each individual pod must be picked by hand just as it begins to split on the end. Overmatured fruits are likely to split, causing a reduction in market value. Its commercial value is fixed based on the length and appearance of the pod.

The main species harvested for vanilla is V. planifolia. Although it is native to Mexico, it is now widely grown throughout the tropics. Today vanilla is grown by Madagascar, Indonesia, Mexico, Tahiti and few other countries including Sri Lanka as a commercial crop.

Major Growing Areas

In Sri Lanka vanilla is mainly confined as a home garden crop grown in mid and low country wet zone. Total extent is less than 100ha. and main growing areas are Kandy, Nuweraeliya,Matale and Kegalle districts.

Varieties

No specific varieties have been identified in Sri Lanka and planting material is taken from traditionally grown vines.

Soils and Climatic needs

Soil : High fertile well drained loamy soils are preferable. Soils should be rich in organic matter.

Climate :

Altitude - Vanilla performs well up to 1000m above the mean sea level.
Temperature – 21-32 0C is suitable. But Vanilla performs well at 27 0C
Rainfall – 2000-2500 mm. But 2-3 months dry spell is needed for flower initiation.

Crop establishment

Planting material
Vegetative methods are practiced. Cuttings, 3’-4.5’ (1-1.5m) in size, are obtained from selected mother vines. Lower end of the cuttings should be closer to the node and 3-4 leaves should be removed from the lower end. To induce buds cuttings should be hanged on a support for about 7 days.

Field Planting
Vanilla is a shade loving plant hence live support trees are used to provide adequate shade (50-60%). Glyricidia is the most suitable shade tree and support trees should be established at least six months before planting vanilla.

Spacing – 3m x 1.5 m (10’ x 5’) (2000 cuttings / ha)

Planting should be done with the on set of rain. Loosen the soil around the base of support up to 8’’ deep in and area of about 2’ in diameter. Then add 2-3 basket of organic manure. Make a furrow 10 (4’’) deep (from support tree and across the surface of planting pit.) and place the cutting horizontally in the furrow leaving 3 cm from lower cut end jutting out into air . Cuttings should be buried firmly with upturned soil. The upper end of the cutting is tied up on to the support tree and mulching should be done up to thickness of 7.5 – 15 cm using decayed organic matter.

Crop management

Training of vines -
When cuttings start to grow emerging axial buds should be trained to turn vines to grow upward direction. When vines reach top of the support tree they should be allowed to droop. When reached to ground let them to grow on soil further 30 -45 cm (1-1.5’) and then curl the stem upwards and allow the buds to grow up again on the support tree. This process should be repeated until vines form several loops. Ground area of loops should be covered with organic manure.

Stimulate flowering –
To get the maximum number of flowers flowering should be induced artificially. Usually this practice is done in January. For that 5-7 nodes are removed from the tip of drooped matured branches. To get 70-80% sunlight shade trees too should be pruned.

Manuring –
Usually artificial fertilizer is not applied to vanilla but organic fertilizer is essential. Compost should be applied at the beginning of each rainy season. Plants should be mulched at least once in six month with dry or fresh leaves and lopping of shade trees.

Pollination –
In vanilla artificial pollination is essential as the natural pollination rarely produce pods. Flower is self-fertile, but incapable of self-pollination without the aid of an outside agency to either transfer the pollen from the anther to the stigma or to lift the flap or rostellum and press the anther against the stigma. Usually flowers come out in April-/ May period and flowers are small lily like, greenish-yellow in colour. There are about 20 flowers in a raceme. Usually, only one flower in a raceme opens in a day, with the entire flowering period of the raceme lasting an average of 24 days. The flower opens in the morning and closes in the afternoon, never to re-open. If it is not pollinated, it will shed the next day. The optimum time for pollination is in mid morning.

Crop Protection

No economically important pests and diseases have been reported
Harvesting and Post Harvest practices
Harvesting –
Pods reach maturity after 8-9 months from pollination. Harvesting mainly falls in December- January. Ideal stage is when tip of the green pods start turning yellow and before split opened of the lower end of pods. In harvesting only mature pods should be e harvested. To make one kg of pods 70 -100 well ripened pods are needed and 6 kg of raw pods are needed to make 1kg of cured pods. Pods must atleast be longer than 6cm and better quality pods must be longer than 10cm. To get quality bulk of pods small pods ( Less tan 10 cm long) should be removed from the plants 2 months after pollination and allow only 8-10 pods in a bunch and remove all other pods. Pods should be plucked by turning upright and should not be used pair of scissors or knife to avoid fungus formed in cut end.

Yield – After 3 years of planting 500 – 800 kg/ha and peak yield level at 8years

Processing
There are several methods of processing but basic steps in each and every method are same. Those steps are

Killing or Wilting – Initiates the on set of enzymatic reactions responsible for the production of aroma and flavor. Pods become brown in color.

Sweating - Increase the temperature to promote the enzymatic reactions and to provoke fairly rapid drying to prevent harmful fermentations, Develop deep brown coloration of pods.

Drying – Slow drying. Beans reach to one-third of their original weight

Conditioning – Store in closed boxes for a period of three months or longer to permit the full development of desired aroma and flavor

The aroma and flavor of the cured vanilla bean/pod are the characteristics that determine the bean’s commercial value on the world market. Processing should be done carefully to preserve the maximum aroma and flavor as well as the physical appearance. Once the mature vanilla beans have been picked, they are taken to the curing and sorted according to size and condition. Sorted beans are plunged into large vats of hot water (63 degrees Celsius) and quickly drained. The warm beans are wrapped in dark colored cotton fabric and after a day they are laid on slatted platforms to dry in the open sun for an hour. For about a week, the beans are left for two hours a day to dry in the sun and rolled in cloth between drying session. At this stage the vanilla beans have become quite supple. For the next two or three months the vanilla beans are spread on racks in the shade or in well-ventilated rooms to allow their full flavor and fragrance to develop. After the curing process, vanilla beans are sorted in an open airy place and graded according to length before they are bundled for shipment. By this time, their aroma is quite remarkable.

Standard quality specifications

Length of pods – between 17-25cm
Smell - Inherited vanilla smell
Color – Dark brown or black color
Appearance - Shiny oily surface
Lack of insect attacks or other patches
Cleanness – Lack of extraneous matter, animal o plant parts or insects
Moisture – around 25%-30%