A single-fold vanilla extract is probably what you're used to buying at the grocery store. It has a weaker flavor, using about ¼-ounce of vanilla beans (about 3-4 beans) per 8 ounces of alcohol. This recipe is for double-fold vanilla extract, which has a much stronger flavor and uses anywhere from ½-1 ounce of vanilla beans (about 5-8 beans) per 8 ounces of alcohol. I find the sweet spot to be right around the 5-6 bean mark for the best balance of price and flavor.