These limited edition Barrel Aged Black Walnut bitters take 18 months to produce. After the 2015 harvest of the unripe 'green' Black Walnuts they do an extended maceration with some of the herbs and spices. Once strained the bitters are rested for 14 months before we add more herbs and spices for another extended maceration. Once strained the bitters are barrel aged to perfection. They are definitely a delicious labor of love. And you are welcome!