is taken to refer to a vanilla-custard flavor. Chemistry Vanilla essence occurs in two forms. Real seedpod extract is a complex mixture of several hundred different compounds, including vanillin, acetaldehyde, acetic acid, furfural, hexanoic acid, 4-hydroxybenzaldehyde, eugenol, methyl cinnamate, and isobutyric acid. Synthetic essence consists of a solution of synthetic vanillin in ethanol. The chemical compound vanillin (4-hydroxy-3-methoxybenzaldehyde) is a major contributor to the characteristic flavor and aroma of real vanilla and is the main flavor component of cured vanilla beans. Vanillin was first isolated from vanilla pods by Gobley in 1858. By 1874, it had been obtained from glycosides of pine tree sap, temporarily causing a depression in the natural vanilla industry. Vanillin can be easily synthesized from various raw materials, but the majority of food-grade (> 99% pure) vanillin is made from guaiacol. Cultivation In general, quality vanilla only comes from good vines and through careful production methods. Commercial vanilla production can be performed under open field and "greenhouse" operations. The two production systems share these similarities: Plant height and number of years before producing the first grains Shade necessities Amount of organic matter needed A tree or frame to grow around (bamboo, coconut or Erythrina lanceolata) Labor intensity (pollination and harvest activities) Vanilla grows best in a hot, humid climate from sea level to an elevation of 1,500 m. The ideal climate has moderate rainfall, 1,500–3,000 mm, evenly distributed through 10 months of the year. Optimum temperatures for cultivation are during the day and during the night. Ideal humidity is around 80%, and under normal greenhouse conditions, it can be achieved by an evaporative cooler. However, since greenhouse vanilla is grown near the equator and under polymer (HDPE) netting (shading of 50%), this humidity can be achieved by the environment. Most successful vanilla growing and processing is done in the region within 10 to 20° of the equator. Soils for vanilla cultivation should be loose, with high organic matter content and loamy texture. They must be well drained, and a slight slope helps in this condition. Soil pH has not been well documented, but some researchers have indicated an optimum soil pH around 5.3. Mulch is very important for proper growth of the vine, and a considerable portion of mulch should be placed in the base of the vine. Fertilization varies with soil conditions, but general recommendations are: 40 to 60 g of N, 20 to 30