Sandalwood oil is extracted from the heartwood of sandalwood trees using steam distillation, a process that takes anywhere from 10 to 24 hours depending on the scale and setup. It’s one of the most time-intensive essential oils to produce, both because the wood requires extensive preparation and because the aromatic compounds release slowly. Here’s what the full process involves, whether you’re curious about how it’s done commercially or considering a small-scale setup at home.
Why the Wood Matters More Than the Method
Sandalwood oil comes specifically from the heartwood, the dense, dark inner core of the tree. The sapwood (outer layers) contains almost none of the fragrant compounds that make sandalwood valuable. This is the first major challenge: sandalwood trees don’t develop usable heartwood until they’re at least 10 to 15 years old. Research on 7-year-old plantation trees found that none had formed heartwood naturally at standard trunk height, making them essentially useless for oil production.
The roots contain the highest concentration of oil, around 10%, while heartwood chips yield between 1.5% and 6% depending on the wood’s color, age, and origin. Light-colored heartwood tends to yield more oil (3 to 6%) than dark brown wood (about 2.5%). That means even under ideal conditions, a kilogram of heartwood produces only 15 to 60 milliliters of oil.
Two species dominate the market. Indian sandalwood (Santalum album) produces the highest-quality oil, with up to 90% santalol content, the compound responsible for the characteristic warm, creamy scent. Australian sandalwood (Santalum spicatum) is more widely available and yields a similar volume of oil, but its santalol content is significantly lower, typically 39 to 46%. The ISO standard for authentic sandalwood oil requires a minimum of 90% santalol, which only Indian sandalwood reliably meets.
Preparing the Wood for Distillation
Raw heartwood needs to be broken down before any oil can be extracted. Commercial operations grind the wood into a fine powder, typically around 2 millimeters in particle size. Smaller particles expose more surface area to steam, which dramatically improves oil recovery. If you’re working at home with a small distillation kit, a wood chipper or heavy-duty grinder can reduce heartwood pieces to chips, though achieving a true fine powder without industrial equipment is difficult.
Once ground, the powder is soaked in cold water for 48 hours. This pre-soaking step is critical. It softens the wood fibers and helps the steam penetrate deeper into the material during distillation, drawing out oil that would otherwise remain trapped. Skip this step and you’ll lose a significant portion of your potential yield.
The Steam Distillation Process
Steam distillation works by passing hot steam through the prepared wood. The heat breaks open the oil-containing cells in the heartwood, and the steam carries the volatile oil compounds upward as a vapor. That vapor then passes through a cooling condenser, where it turns back into liquid. Since sandalwood oil is less dense than water, the two liquids naturally separate: the oil floats on top and can be collected.
Commercial Scale
In commercial distillation, the soaked wood powder is loaded into a large steel still along with water. Steam is introduced at low pressure, around 10 psi (0.7 bar). Keeping the pressure low is important because excessive heat can damage the delicate santalol compounds that give the oil its quality. A typical commercial batch runs for 10 to 24 hours. Longer distillation times pull more oil from the wood, with 24-hour runs yielding up to 3.6% oil by weight. Shorter runs of around 10 hours at the same pressure yield closer to 1.6%.
The condensed liquid collects in a device called a Florentine separator (essentially a tall container with an outlet near the bottom). The oil rises to the surface and is skimmed or drained off, while the water underneath, now called hydrosol or sandalwood water, exits through the lower outlet. The hydrosol retains a mild fragrance and is sometimes used separately in skincare.
Small-Scale and Home Setup
Home distillation kits designed for essential oils typically include a small boiler (around 2 liters), a column or vertical tube, a sieve to hold the plant material above the water line, a condenser with cooling water running through it, and an oil separator for collecting the output. Glass versions based on the Clevenger apparatus design are particularly effective for sandalwood because they allow continuous distillation, recycling the water back through the system over many hours.
For a home batch, you’d place your soaked, ground sandalwood on the sieve inside the column, fill the boiler with water, and heat it to produce steam. The steam rises through the wood, picks up the oil, and travels into the condenser. Cold tap water flowing around the condenser tube cools the vapor back into liquid, which drips into the oil separator. You’ll need patience: plan on running the distillation for at least 10 hours, and ideally closer to 20, to get a meaningful amount of oil.
Expect a very small yield. With 150 to 200 grams of heartwood powder (a realistic amount for a home kit), you may collect only a few milliliters of oil at best. Research trials using steam distillation with a Clevenger apparatus and 150 to 187 grams of heartwood ran for 20 to 24 hours to achieve usable quantities.
Separating and Finishing the Oil
The liquid that comes out of the condenser is a mixture of oil and water. In most setups, the oil separator handles the initial split by gravity: the oil floats, the water sinks. If you’re using a basic kit without a built-in separator, you can pour the collected liquid into a narrow glass container, let it sit for an hour, and use a pipette to carefully draw off the oil layer from the top.
For cleaner oil, any remaining moisture can be removed by letting the oil sit over a small amount of anhydrous sodium sulfate (a common drying agent available from chemical suppliers) for a few hours, then filtering it through a coffee filter or fine cloth. Commercial producers may use vacuum distillation or other purification steps to isolate specific compounds, but for home use, the gravity-separated oil is ready to use as-is after drying.
Why Yields Are Low and Costs Are High
Several factors work against you when making sandalwood oil. The trees take over a decade to develop usable heartwood. The oil is locked deep within dense wood fibers and releases slowly even under steam. And the yield per kilogram of raw material is among the lowest of any essential oil. Commercial operations compensate by processing hundreds of kilograms per batch and running distillation for a full day.
For a home distiller, the biggest practical barrier is sourcing authentic heartwood. Indian sandalwood is heavily regulated due to overharvesting, and genuine Santalum album heartwood is expensive, often $50 to $100 or more per kilogram. Australian sandalwood is more accessible but produces a lower-quality oil. Either way, the math is sobering: even at a generous 3% yield, one kilogram of heartwood produces only about 30 milliliters of oil.
If your goal is to have sandalwood oil for personal use, purchasing it from a reputable essential oil supplier is almost always more practical than distilling it yourself. But if you’re interested in the craft of distillation or want to understand firsthand how essential oils are made, sandalwood is a fascinating (if demanding) material to work with. Just go in knowing that the process rewards patience and that even small quantities of genuine sandalwood oil represent hours of careful work.