This is one of my favorite ingredients and essential in the pastry kitchen. Vanilla beans come from the fruit of an orchid and are not cheap, second only to saffron in costly spices. So, you want to pick a good one and use the whole thing, pod and seeds. The beans should be soft, oily and have an intense vanilla aroma. Avoid a bean that has no luster, is dry and brittle.
Here is an overview of a few different types of vanilla beans:
Mexican beans are the original and most highly prized beans. They have a mellow, smooth, quality and a spicy, woody fragrance.
Madagascar Bourbon beans are long and slender, with a very rich taste and smell, have thick, oily skin, contain an abundance of tiny seeds, and have a strong vanilla aroma. They are also considered high quality bean and reflect this in the cost. This is where most the worlds vanilla come from. The name refers to the region they are grown and is not at all related to the booze.
Tahitian beans are usually shorter, plumper, and contain a higher oil and water content than Bourbon beans. The skin is thinner, they contain fewer seeds, and the aroma is fruity and floral. They are often described as smelling like licorice, cherry, prunes, or wine.
You will have to get your hands on them all and decide for yourself which is your favorite. There are others, but they are hard to come by, if this changes I will update the post.
You want to store your vanilla beans in a airtight container, in a cool, dark spot. If you buy them in bulk and won’t be using them all at once you can throw them in the freezer to prevent them from drying out.