The oil is amber brown and viscous. Its odor is described as deep, sweet, woody, smoky, earthy, amber and balsam. The best quality oil is obtained from 18- to 24-month-old roots. The roots are dug up, cleaned, and then dried. Before distillation, the roots are chopped and soaked in water. The distillation process can take up to 24 hours. After the distillate separates into the essential oil and hydrosol, the oil is skimmed off and allowed to age for a few months to allow some undesirable notes formed during distillation to dissipate. Like patchouli and sandalwood essential oils, vetiver's odor develops and improves with aging. The oil's characteristics can vary significantly depending on where the grass is grown and the climate and soil conditions. The oil distilled in Haiti and Réunion has a more floral quality and is considered of higher quality than the smokier oil from Java. In north India, oil is distilled from wild-growing vetiver. This oil is known as "khus" or "khas", and in India is considered superior to the oil obtained from the cultivated variety. It is rarely found in commerce outside of India, as most of it is consumed within the country.