2.8 ml is sufficient for 1 LT. Obtained by Water Vapor Distillation. It is not Aroma or Essence, it is 100% Organic Pure Anise Oil. Since our anise crystallizes below 20 degrees, it will arrive in a frozen state, which is an indicator of its quality. You can melt it easily using the double boiler method. 100% Customer Satisfaction (After-Sales Support.) User Manual and Dropper are Sent with the Product. You can store it at room temperature.