It may be too much information, but here's an excerpt from my upcoming book "Experimental Brewing"...
Vanilla can be used in several different forms. Start by obtaining
the best vanilla you can find, whether it’s vanilla beans or extract.
Beans should be moist, pliable, fat, and “juicy”. Extract should not
have any fake aromas or flavors to it. Some extracts are made with
wood byproducts. Although some of these may be good, a lot of them
are not. Do some research and be prepared to audition different
forms from different sources to make your choice. Be careful as some
extracts of dubious quality use the tonka bean, which, in addition to
vanilla, also provides coumarin, a powerful liver toxin. We recommend
that you buy beans online because they are generally cheaper and
higher quality than anything you’ll find in the grocery store. Another
bonus, you can also usually find “Grade B” beans, which aren’t as
pretty as “Grade A”, but work dandy. They’re also a lot cheaper,
usually around 1/3rd the price! Bourbon Vanilla: When you think
vanilla, this is the flavor that you think of. It’s a big potent blast
of vanillin, the main active flavorant associated with vanilla. The
bold character makes it perfect for anything that you want people to
smell and taste and immediately say “VANILLA!” Historical note: The
Bourbon name has nothing to do with Bourbon whiskey. Both Bourbon
County, Kentucky and Bourbon Island (aka Réunion Island off the coast
of Madgascar) get their name from the French Royal House of Bourbon.
Mexican Vanilla: Made from the same Vanilla planifolia orchid as the
Bourbon vanillas, the Mexican vanilla flavor is lightly smokey and not
as buttery as the Bourbon variety. Tahitian Vanilla: From the V.
tahitiensis orchid, Tahitian vanilla is a softer and more perfumey
with a strong floral note that makes it preferred by pastry chefs for
subtle applications. This is the one you reach for when you want your
tasters to be puzzled and pleased Ugandan Vanilla: Also grown from a
variety of V. planifolia, the Ugandan beans are consider the world’s
most potent and provide an additional tone of chocolate from the dark
leathery bean. Vanilla beans can be added straight to a fermenter
after fermentation is complete. Split the beans lengthwise and use a
knife to scrape out all the gooey goodness inside. That’s where most
of the flavor comes from. Add that to the fermenter, than coarsely
chop up the pod and add that, too. Start tasting after about 5 days
to see if you have level of vanilla you want. The vanilla flavor and
aroma fades sooner than a lot of other beer flavors, so you may want
to let it get a little stronger than you think is needed so that in a
few weeks the flavor will be right. The number of beans to use will
depend on the size and quality of the beans, the amount of vanilla
character you want, and the base beer. 2 beans per 5 gallons is a
good place to start. Vanilla extract can be added directly at
packaging using the titration process described above for coffee. Oh
and the best vanilla extract you can use? Homemade with the tincture
recipe using the best beans you can find. One thing Drew keeps on his
shelf is a collection of 3 different types of vanilla – Bourbon,
Mexican and Tahitian. Each of the bean types offers a different flavor
profile that you can use to generate a different effect. Even better,
you can blend them in different ratios to achieve a different effect.
Imagine a Belgian Tripel spiced with a touch of Ugandan and a big
splash of Tahitian. With a cool ferment you’d end up with a barely
vanilla and chocolate cake topped with flowers. If that doesn’t say
special occasion what does?
Here's the titration technique referred to...
Pour 4 2 oz. samples of the beer (before adding your priming if you’re
bottling). Add a different, measured dose of the flavoring to each
sample and taste critically. Maybe even have someone else taste, too,
so you can find a consensus amount. Then scale the amount of
flavoring in the sample you prefer up to the size of your entire batch
