Carton of hemp milk. Hemp milk or hemp seed milk, is a plant milk made from hemp seeds that are soaked and ground in water, yielding a beany-nutty cream flavored substance.There are various options available for purchase including organic, non-GMO and conventional: unsweetened, original, vanilla and chocolate-flavored options.roduction of hemp milk hemp seeds, water and a blender. Many recipes call for ground vanilla or vanilla extract to add more flavor and a type of sweetener.