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Cocoa, coffee and spice from Madagascar, Réunion, Comoros, Mexico, Indonesia, India and other vanilla-growing countries

Vanilla curing

Curing turns green, scentless vanilla pods into brown, fragrant beans in four steps, killing, sweating, drying and conditioning, over several months. The change is mainly enzymatic, so it is a boundary entry. Once heat or cold breaks the pod's cells, its own β-glucosidase splits glucovanillin into vanillin and glucose, while Bacillus bacteria grow on the pods and may help.

Fully documentedCocoa, coffee and spice2.3 months – 3.7 months

Recipe

No fixed amounts recordedThe FAO compendium gives a method, not a batch size. Green beans weigh 4.5 to 6 times as much as cured beans, depending on grade.
Mature green vanilla pods (Vanilla planifolia)Best picked one by one when the blossom end is yellow; curing should start within a week of harvest[fao-vanilla]
Water heated for killing (in the hot-water method)[fao-vanilla]
Woollen blankets and wooden boxes for sweating[fao-vanilla]
StarterThe pod's own β-glucosidase begins splitting vanillin from its glucoside early in curing.

Total time across the recorded steps: 2.3 months – 3.7 months

Start
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What changes: Starting material: green vanilla pods, yellowing at the blossom end

Step 1 of 6
Pick the ripe green pods
Time
Not documented
Temperature
Not documented
Salt
None given
Acidity
Not documented
Which microbes the steps name, step by step
Bacillus

Pods are ready six to nine months after pollination. Picked too early they give an undeveloped flavour and are easily attacked by fungi.

Flavour
Not documented
Texture
Not documented
Colour
green, yellow at the blossom end

Microbes at work in this step

Not documented for this step.

Method

Measured measured in a studySet fixed by a specification or tested recipeReported one source reports itTypical a general value, not sourced for this fermentUnconfirmed not yet checked against a source

At a glance

Curing turns green, scentless vanilla pods into brown, fragrant beans in four steps, killing, sweating, drying and conditioning, over several months. The change is mainly enzymatic, so it is a boundary entry. Once heat or cold breaks the pod's cells, its own β-glucosidase splits glucovanillin into vanillin and glucose, while Bacillus bacteria grow on the pods and may help. Made in 6 steps over 2.3 months – 3.7 months. The longest step, condition in closed boxes, takes at least 2 months (De La Cruz Medina J 2009). Bacillus, the main bacterial genus on curing and cured pods, positively linked to glucovanillin; its role beside the pod's own enzymes is still being studied does most of the fermenting.

Key numbers
Main stepat least 2 monthsReported[fao-vanilla]Condition in closed boxes
Temperature65–70 °CReported[fao-vanilla]Kill the pods

What makes this one different

Called fermentation in trade, but the change is mainly enzymatic. The pod's own β-glucosidase releases vanillin after killing breaks the cells; Bacillus grows on the pods, and its part is still being studied.

Vanillin
Export quality table quoted by FAO asks for at least 2.0 % vanillin; a 2025 study cites 0.75 to 4.58 % in cured pods
Moisture and aroma
Beans at 50–54 % moisture smell fermented; at 24–27 % the aroma is well developed (Arana, cited by FAO)
Grades by colour
Brown vanilla, chocolate brown, has 18–22 % moisture; black ('gourmet') vanilla has 25–35 %

Related ferments

Variants

  • Mexican sun or oven killingPods are wilted in the sun under dark woollen blankets, or in an oven at 60 °C, instead of dipped in hot water.
  • Hainan hot-air curingIn a Chinese study the beans were blanched at 70 °C for 5 min, sunned for about 6 h a day, sweated in cotton blankets in an oven at 55 °C for 6 h a day for 6 days, dried to 30% moisture and conditioned in closed boxes for 6 months.
  • Madagascar tunnel curingHot-air drying tunnels replace the sun and give even, good-quality beans in large lots.

Safety

Uneven drying, dirty blankets and poor ventilation let mould in, and long initial sweating starts rot. Beans are checked daily and mouldy ones removed. The export quality table quoted by FAO sets limits for moulds, aflatoxins, E. coli, B. cereus, Clostridium, S. aureus and Salmonella.

Hazards the sources name: Bacillus cereus, Escherichia coli, sulphite-reducing Clostridium, Staphylococcus aureus and Salmonella (limits in the export quality table quoted by FAO).

History and sources

Every number is labelled with how it is known. How this atlas is made

Vanilla comes from Mexico and Central America. The FAO compendium describes hot-water killing in Madagascar, Réunion and the Comoros, sun wilting in Mexico and Indonesia, oven wilting at 60 °C in Mexico, and freezing tried experimentally in Puerto Rico.

  1. [fao-vanilla] De La Cruz Medina J., Rodriguez Jiménes G.C., García H.S. et al., Vanilla - Post-harvest Operations, FAO Post-harvest Compendium (INPhO), last reviewed 16 June 2009gov
  2. [cuan2025] Cuan-Escobar T.A., Cuellar-Sánchez A., Gómez-Velázquez H.D.J. et al. 2025, Effect of different killing methods during curing on the phytochemical and bacterial composition of Vanilla planifolia using multi-omic approaches, Food Chemistry X 26:102269, doi:10.1016/j.fochx.2025.102269paper
  3. [xu2020] Xu F., Chen Y., Cai Y., Gu F., An K. 2020, Distinct roles for bacterial and fungal communities during the curing of vanilla, Frontiers in Microbiology 11:552388, doi:10.3389/fmicb.2020.552388paper