Harvesting: Vanilla beans are ready for harvest in six to nine months after pollination. The beans are harvested one by one when they are fully-grown and as they begin to ripe. At this stage, beans change their colour from dark green to light green with yellow tinge. Immature beans produce an inferior product and, if picked too late, the beans start splitting. Bunch or broom harvesting should be avoided. The well-ripened ready beans detach easily from the bunch just by lifting them in reverse direction. Immature beans do not detach easily from the stalk; but, on the other hand, leave behind a bit of the bean in the bunch. Hence, to pick the beans at right stage, the plantation should be visited two or three times a week. The green beans do not possess any aroma. Processing and curing should commence within a week of harvest.
Sorting and Grading: Size and appearance get the primary importance here, since; there is a direct relationship between the aroma (or vanillin content) and these factors. The beans are classified according to their length as follows:
|Grade of Beans||Length of Beans|
|A||15 cm and >|
|C||Less Then 10 cm|
|D||Splits, cuts and damaged beans|
Cleaning: The graded beans are washed with clean water.
Killing: Graded beans are transferred to a bamboo basket and immersed in hot water at a temperature of 70oC for periods as indicated below:
|Grade of Beans||Period of immersion|
Sweating: The treated beans are then transferred immediately to a wooden box lined with blanket, for sweating and kept for 36-48 hours. The temperature initially is to be 48-50oC. By then, the beans will attain light brown colour and start imparting aroma.
Sun drying: Later on, the beans are spread in hot sun (from 12 noon to 3 pm) over wooden loft on a clean black blanket. The temperature of the bean, at this time should raise to 50oC. Later on, the bundles are transferred to the sweating box. Sun drying and sweating is continued grade-wise, as follows:
|Grade of Beans||Period|
At the end of this period, the beans lose half of initial weight, turn to a shining dark brown colour and develop wrinkles. Also, their aroma improves.
Slow drying: The next step involves the spreading of the beans in racks kept in well-ventilated room maintained around a temperature of 35oC and relative humidity of 70 per cent. The duration of slow drying is as follows:
|Grade of Beans||Period|
On completion of slow drying, the vanilla beans get heavy longitudinal wrinkles, turn lustrous with brownish black colour and become supple. They offer a soft leathery touch; can be rolled around finger easily and on release, becoming straight. The moisture content at this stage may be around 30-35 per cent.
Conditioning: The dried and classified beans are bundled (150 – 250 gm each), tied with a thread and kept for conditioning inside wooden or metal boxes lined with wax paper for two months. By this time, there is a further loss of three to four per cent moisture with the full development fragrance. Finally, the bundles are wrapped in wax papers and stored in airtight containers. The reduction in weight from green to conditioned beans ranges from 4.5:1 to 6:1, depending on the grade.
On the whole, meticulous care has to be taken during the curing process, as otherwise the quality of the beans may get deteriorated due to fungal, bacterial or other pest damage.
Points to remember:
- To get quality and sustainable yield, organic farming technique is to be adopted.
- Curing of green beans is to be commenced within a week of harvest.
- Matured, light green with tinge of yellow coloured beans are to be harvested individually, avoiding broom harvesting.
- For heat killing, temperature of water should not exceed 65-70oC.
- Initial sweating is to be for 24 to 48 hours. Extension of this period will initiate rotting.
- Daily sun drying is to be followed by proper sweating for controlled fermentation.
- The beans are to be examined everyday during sun drying and slow drying for avoiding infection.
- Moulds, if noticed, has to be removed from time to time. These beans are kept away from other beans.
- As in the previous steps, beans are to be checked regularly, during conditioning too; to avoid any infection.