What is the difference in vanilla grown in different regions of the world?
Mexican vanilla beans are harvested when the tips of the green beans begin to turn yellow. That is a good indication that the beans are ripe enough to cure. Those beans are wrapped in straw mats or thick blankets and placed in a heating oven for 1-2 days. Once that process is complete, beans are spread out and absorb sunlight every day. They are then placed onto racks or curing boxes to further develop aromatics.
Madagascan vanilla's curing process is very similar to Mexico, except the beans are scalded in hot water for a couple minutes. The beans are then stored in sweating boxes for a couple weeks before spreading them in the sun to cure. This helps the beans to begin losing moisture, facilitating the enzymatic process to convert sugars into vanillin, and also to concentrate aromatics within the bean. This creates the distinct and complex flavor profile of Madagascan vanilla beans.
Tahitian vanilla is cured differently than in Madagascar or Mexico. Mature beans are stacked in a cool place for 5-10 days, until they turn brown. They are then rinsed in clear water to clean off any debris. Over the period of a month, growers place the beans in the sun for 3-4 hours a day. In the afternoon, they wrap the beans in cloth and store them in a large box to "sweat" promoting moisture loss, causing the beans to shrink. Throughout this process, the beans are smoothened and flattened by hand with the use of their fingers. After the beans are done curing in the sunlight, they spend the next 40 days in a cool, shaded, and ventilated area where they reach their target moisture.
Indonesian vanilla has used many curing methods over the years. Many islands have expanded product to meet the growing demands throughout the world. Initially, curing methods were similar to Mexican vanilla where fire was used to cure beans quickly, resulting in woody and tobacco flavor profiles. Over the years, there are plantations switching over to the Madagascan way of curing to bring out more complex flavor profiles, and to eliminate the smoky/tobacco profiles. Because of the evolving methods of curing, they also expose beans to greater amounts of sunlight, making these beans more resistant to heat and can hold up well in baking applications.
Papua New Guinea uses the same curing methods as Madagascan vanilla. However, the vast majority of vanilla produced in Madagascar is Vanilla Planifolia, and in PNG, it is Vanilla Tahitensis. Vanilla is very hit-or-miss from this region. Some blame smugglers from other areas; bringing unripe or poorly cured beans in the region to damage the reputation of PNG vanilla. Others say that market prices are being driven down by suppliers and in order to meet demand, PNG farmers are cutting beans too early or not finishing the curing process before being sold.
So what does all of this mean? Vanilla beans are like wine. Each has it's own notes and profiles, but not everyone is a connoisseur. There is a wine and a vanilla for everyone. Experiment and see what you like the best. At the end of the day, a well-cured bean is just that. Always make sure you know exactly what you are getting and from a supplier you trust, because a poorly cured bean is not fit for consumption.