Take 5 whole vanilla beans, split lengthwise and add to 8 ounces of 35%+ alcohol. Any type of alcohol can be used, but bottom shelf vodka is most common because it will not add any additional flavors to the extract. Bourbon, rum and brandy can also be used. After 8 short weeks the extract is ready to enjoy. Remove the beans at that point
I do recommend glass bottles.
Do the same as above but using the amounts specified above