Natural Peanut Butter Flavor Extract - 128 oz.Natural Peanut Butter Flavoring 128 oz Bottle. Great for beer. Making a Peanut Butter Stout? This will get you that Peanut Butter Flavor. Directions for use: Start with adding 1 oz of flavoring per 1 gallon of your beer or wine. From there you may add until you are happy with the taste. If you are bottling, add to the beer when you add the priming sugar If you are kegging, add when the beer is poured into the keg. If you are using with wine, add to