The Art of Curing
Vanilla beans don’t come off the vine black and shiny as we know and love them.
They start out green, their tips yellowing as they ripen and loosen their grip on the mother plant. At that moment of harvest, the vanilla bean begins a fraught and arduous four-month metamorphosis.
Few ingredients in the food world match this journey.
Before we start, a warning. Nothing can cure an unripe bean. Like berries and many fruits, vanilla stops ripening the moment it is picked.
As Linda Ronstadt put it:
“Love is a rose but you better not pick it. Only grows when it’s on the vine. Handful of thorns and you’ll know you’ve missed it. Lose your love when you say the word mine.”
That’s vanilla for you, the diva of the food world. And never more so than in today’s market, where a kilo of beans can equal a year’s wages for workers in the countries where it grows. Farmers face dire risk of theft every moment the beans stay outside. And after nine months of backbreaking toil, farmers are often cash-poor and need to put food on the table. The temptation to pick beans too soon can be overpowering.
Yet without natural ripening, a bean cannot become vanilla.
Ripening occurs when temperature and humidity changes trigger the bean’s enzymes to convert starches and pectin to sugars. The pod’s cell walls soften. Chlorophyll breaks down, and the fruit begins to yellow. Interrupting this process arrests flavor development. Curing an unripe bean preserves only a sour and bitter fruit.
Once ripe, the four stages of curing can begin.
Stage 1: DIPPING
No more than three days after harvest, the beans are plunged into water heated to 150-170 degrees Fahrenheit from 10 seconds to three minutes. Timing depends on the size of the beans, whether they have split on the vine, and water temperature. Dipping is performed by a master curer who calculates these variables by feel.
Dipping “kills” the bean, stopping growth and releasing the enzymes that begin production of vanillin, the bean’s primary flavor component.
This converts glucovanillin to vanillin:
Stage 2: SWEATING:
As soon as the beans are pulled from the water, workers rush to wrap them tightly in wool blankets, storing them inside a dark, airtight container. Speed is essential to preserve heat and steam. These trigger the enzymes that convert cellulose and starches to vanillin and other complex components that give vanilla its beautifully subtle aroma.
The beans remain tightly wrapped for up to two weeks, during which it is imperative to keep them warm. Any cooling can trigger mold, vanilla’s arch enemy. Because vanilla is cured during the rainy season, this presents a tricky problem. Curers combat cooling by laying the rolls in the sun and returning them to their container when clouds and rain threaten. As the beans reach a more ideal moisture content, they will be left in the sun open to the air during the day and rolled up at night. Daily sun exposure is paramount to the flavor transformation and the prevention of mold on vanilla beans. This rolling and unrolling continues for up to two months.
Stage 3: DRYING
Once the beans begin to develop aroma and reach the correct moisture, the drying stage begins. Drying is essential to enabling international shipment, because wet beans will mold in transit.
The beans start out quite wet. They are laid in the open air, alternating between sun and shade, driving out moisture. Too much sun can over-dry the beans and destroy vanillin, leaving brittle, useless sticks. The beans are closely monitored and constantly sorted by moisture content. Workers massage each bean by hand to make sure the drying is occurring evenly. Drying usually lasts for 3 to 4 weeks, with a goal of 25-30 percent moisture content.
Stage 4: CONDITIONING
By now, the beans are exploding with aroma and flavor, and almost ready. They are placed in closed boxes lined with wax paper and kept there for at least a month. This preserves and enhances aroma. Beans are often shipped at this stage before conditioning is complete because this is the bean’s final form of storage.
PERFECTION
The box can now finally be opened. The conditioned beans have developed full flavor, and look black and slick with a very light coating of natural oils. Sometimes, when everything happens just right, the beans are clothed in delicate white vanillin crystals.
Things also can go terribly wrong, anywhere along the line. The worst outcome is mold, deadly to bean flavor and a financial disaster for farmers, curers, and buyers alike.
I was fortunate enough to spend three months on the island of Tonga curing vanilla beans, witnessing firsthand how delicate and complicated, how laborious and stressful, the process is. Are the beans warm enough? Are they too wet? Too dry? All this during the Tropical monsoon when weather can shift by the minute.
Vanilla curing is an art. It demands an astute eye and years of experience to know when to move the vanilla beans from one stage to the next. There is nothing like seeing a master curer in action!
You must love vanilla to get it right. But the reward is like no other: to lift the lid of a beautiful hand-packed box of vanilla beans that fills a room with its exotic, intoxicating scent.
Margaret Schmidt Kobel
Chemist
Cook Flavoring Company
My beans are only 1 month old and turning yellow! What can I do to save them?
Hello Karen, if you are talking about cured (black) vanilla beans, then there should be no yellow on your vanilla beans. Cured black vanilla beans are a stable product and will not turn color. If you are talking about green or uncured vanilla beans then this is a natural stage in the plant’s development and signals the time when vanilla beans should be picked from the vine.
Very informative article. Vanilla curing process is very very long. It needs above all patience and passion.
Thank you for you comment! Vanilla is indeed a labor of love!
what type of rope is used for bundling beans ? Thankyou.
Hello Gouvana, thank you for your question! The material depends on the supplier. At Cook’s we buy beans bundled only with cotton string or dried raffia. Our organic beans from Madagascar are exclusively bundled with cotton string, as this is our preferred method. Other materials besides cotton and dried raffia can lead to problems like mold that can taint the beans during shipping.
Hi, I have been given 2 kgs of fresh vanilla beans – do I just put them in the sun?
Hello Karen, thank you for your question. What a generous gift! If you are referring to black (cured) vanilla beans, just keep them in a cool and dry place and in a relatively air-tight container to prevent the beans from drying out too much and use when desired. If you are referring to green vanilla beans, unfortunately the process is very labor intensive and requires many steps including 1. dipping the beans in water at about 65 degrees celcius for a minute or two 2. immediately transferring the beans to some kind of closed container with blankets surrounding it to keep the beans warm and keeping it like that for 3 days 3. sunning them for 2-3 hours per day for about 1 month and wrapping them up in blankets when they are out of the sun 4. drying them in the shade for 2-3 weeks to reduce them to about 20% of the original moisture content of the bean 5. wrapping them in wax paper and then putting them in boxes for 1 month for conditioning. The curing process is both an art and science and the different stages usually require a master curer to determine when the beans should move from one stage to the next. Best of luck to you and enjoy your beans!
Hi there. I am working with a company that prépare and export vanilla beans. We have just both a quick curing machine to cure thé beans without passing all ot those long step le thé process. Thé machine is new for me so To get thé right setting a différent try is required as per thé supplier. Can you help me with thé following. What température should i use and relative humidity of thé machine To get thé vanilla cured when taking it out of thé machine and how long should i put them in? What is thé spécific things i need To be verycareful about when using thé quick curing process To insure vanilla is well cured using thé machine?
Hello Martial,
Thank you for contacting us. Unfortunately, we do not endorse the use of quick cure machines and do not offer information regarding their use. We encourage using the long, traditional method as this always produces better vanilla beans.
Best,
Margaret
Hi
If I need to get 1 kg of dry beans, how many kilos of green beans do I need to use
Hello Ramlan,
To answer your question, typically the curing ration for green to dry vanilla beans is 4:1 or 5:1. This ratio can very on the moisture content of the harvested beans as well as the end grade of the cured vanilla beans (gourmet vs. extract).
I hope this helps you!
Best,
Margaret
Before they were discovered, would they have gone through this process naturally if left alone?
Hello Erica,
In rare cases, sometimes a vanilla bean will cure on the vine. However, most vanilla beans if left on the vine will rot, so it requires a very specific amount of sun and high vanillin content vanilla beans. I hope this answers your question!
Best,
Margaret
Has any one air dried vanilla in a very low temperature oven before? I’m currently experimenting with this process & looks good after the first 2 weeks
Hello Deke,
Thank you for your comment. This method is known as quick curing and is employed by many vanilla curers. We do not purchase quick cured vanilla beans because we find the quality is inferior to the artisanal, traditional method.
Best,
Margaret