Bourbon Vanilla Curing Technique

WARNING:

Too young green vanilla beans (below 7 months old) can't be used for Bourbon technique. To find out why - watch the video below

Vanilla curing is not an activity that every vanilla farmer should try to do. This is because very few people have the knowledge, skills, patience, and willingness to give ongoing attention to the details that are necessary to produce high-quality cured vanilla. Processing vanilla is a seven-day-a-week job for three to four months a year.

For most farmers would be best to sell their ripe vanilla beans to professional curers in their area. This may be another farmer, a cooperative of which they are a member, or a buyer/exporter.

Curing of Ripe Vanilla Beans

Curing of vanilla beans is one of the most important processes affecting the final quality of the cured beans. If it is not done properly very poor quality vanilla will be produced even from beans that were of good quality at harvest. The reason that vanilla beans are cured is to produce as much aroma (smell) and flavor (taste) in the beans as possible. When the beans are mature and harvested, there is very little vanilla aroma and flavor in them, this will be formed as the beans are cured.

Vanillin is the main compound in cured vanilla beans that produces the aroma and flavor. The shiny oily or glossy appearance of good quality cured beans is due to the high vanillin content in the beans and is used to assess the quality of cured beans. Good quality cured beans should be long, shiny, oily, dark brown to black in appearance and free of molds and pests. To achieve this, a lot of care needs to be taken during the harvesting and curing of the beans. Cured beans with little vanillin content are dull and lack shine. Very little aroma and flavor can be produced from immature beans. This is why it is important to pick vanilla beans when they are mature (8-9 months old). Unripe beans will end up as poor quality, dry, hard beans with very little aroma and flavor when cured. The curing process recommended in this article is designed to produce as much aroma and flavor as possible in the vanilla beans. To achieve this, the beans have to be kept at the right temperature and the right moisture level for the correct length of time.

There are four main stages in curing vanilla. These are:

  1. ‘Killing’ or ‘Wilting’ and ‘Initial Sweating’ (keeping the beans hot for two days) - this kills the beans and starts the formation of aroma and flavor.
  2. ‘Sun Sweating’ - a quick drying period in the sun is followed by a long exposure to the sun inside a blanket. The bean temperature rises to about 60°C and the beans are kept hot overnight. This is repeated every day for about 15 days until the moisture content of the beans falls to about 50%. This is the most delicate stage of the curing, where changes in temperature can dramatically enhance or slow down the formation of aroma and flavor.
  3. ‘Slow Drying’ - normally carried out inside a well-ventilated room, until the bean moisture content falls to about 18 to 25%. This further increases the vanillin content of the beans.
  4. ‘Conditioning’ - the beans are stored in airtight containers for a period of about three months to allow the full development of the aroma without any further loss of moisture. There are a number of methods used around the world to cure vanilla. Good quality beans can be obtained from different curing techniques, as long as the stages described before are undertaken. NARI LAES recommends that vanilla be cured using the Bourbon method. This method will consistently produce good quality cured beans from both Planifolia and Tahitensis vanilla under conditions in Indonesia. The Bourbon method is described below.

Vanilla Curing Equipment & Procedures

The following outlines the equipment and the curing techniques needed to properly cure vanilla to premium export quality.

Stage 1: Hot Water Killing (Scalding)

equipment that is needed for Hot Water Killing (Scalding)

Equipment needed:

What to do:

thermo-box for scalded vanilla beans fermentation

Stage 2: Sun Sweating

vanilla beans on sunsweating

Equipment needed:

What to do:

Stage 3: Slow In Shed Drying

bundles of vanilla beans ready for in-box conditionning phase

Equipment needed:

What to do:

Stage 4: ‘In Box’ Conditioning

Equipment needed:

What to do:

Nine important things to remember:

  1. Only harvest ripe beans
  2. Grade and sort the beans before curing
  3. Scald the beans in hot water at 63°C for about three minutes
  4. When sweating beans, use an insulated box (esky) and keep the temperature at 40-60°C
  5. During the sun sweating phase only dry the surface of the beans (one to two hours), then wrap and leave in the sun to heat up for the rest of sun hours
  6. Surface dry and heat the wrapped beans every day until the moisture content falls to 50%
  7. Sweat the beans every night until the moisture content falls to 50%
  8. Slowly dry the beans in open trays in a well-ventilated, dry room when the bean moisture content falls to 50% and inspect the beans daily
  9. When moisture content falls to 18 to 25% put in lined boxes to finish curing and inspect weekly

Time required for Curing Activities

The following is a guide to the time required for each step of vanilla curing. Note that some of the times will vary depending on weather conditions. The required time commitment to cure a batch of harvested beans will be on average a hundred days (over three months). During this time the curer needs to pay full attention to the curing process, which may be difficult for many farmers.

Day 1: Scalding

Day and night 1-2: ‘In Box’ Sweating (fermenting)

Day 3-15: Curing Phase

Night 3-15: ‘In Box’ Sweating

Days 16-100: ‘In Shed’ Curing and ‘In Box’ Curing