Extraction Science
Raw cannabis extract is a mix of cannabinoids, terpenes, waxes, and plant lipids. Distillation is the process licensed labs use to separate those out — and terpenes, which carry almost all of a strain's flavor and aroma, are also the most fragile part of that mix. Capturing them well is a big part of what separates a flat-tasting distillate from something that actually tastes like the strain it came from.
Terpenes are volatile compounds — they boil off, oxidize, and degrade at far lower temperatures than cannabinoids like THC or CBD. Run a standard distillation without accounting for that, and the terpenes are gone before the cannabinoids are even separated, leaving a technically potent but flavorless distillate. Preserving them means either capturing them in a separate pass before the heavier cannabinoid fractions are pulled, or reintroducing terpenes after the fact.
Every compound in the mix has a different boiling point, and under vacuum those boiling points all drop — which is the whole reason vacuum distillation is used instead of distilling at normal atmospheric pressure. The relative order stays roughly the same though, which is what makes separation possible in the first place.
| Compound | Approx. boiling point (atmospheric) | Role |
|---|---|---|
| Pinene | ~155–156°C | Terpene — pine, sharp |
| Myrcene | ~165–168°C | Terpene — earthy, musky |
| Limonene | ~175–178°C | Terpene — citrus |
| Linalool | ~198–200°C | Terpene — floral |
| Caryophyllene | ~250–260°C | Terpene — peppery, heaviest common terpene |
| THC | ~157°C under vacuum (~200°C+ at atmospheric) | Cannabinoid |
| CBD | ~160–180°C under vacuum | Cannabinoid |
Those figures are approximate reference ranges commonly cited in extraction literature, not fixed constants — actual behavior shifts with the vacuum level, the mixture's composition, and the specific equipment run. Every licensed processor validates their own parameters rather than working off a generic chart.
The foundation underneath nearly every method below. Pulling a vacuum drops the pressure inside the system, which lowers every compound's boiling point. That lets processors separate heat-sensitive terpenes and cannabinoids at temperatures well below what would degrade them at normal atmospheric pressure.
A glass apparatus where vapor travels a short physical distance from the heated flask to the condenser before condensing back into liquid. It's typically run as a batch process — one load in, one distillate out — which makes it common for smaller-scale or craft operations, and it lets an operator visually monitor the distillation as it happens.
A continuous-flow method: a rotating wiper spreads a thin film of oil across the inside of a heated cylinder under high vacuum. Because the oil is only a thin film on a hot surface for a fraction of a second before being drawn off, it spends far less time exposed to heat than in short path distillation — which generally means better preservation of heat-sensitive compounds and higher throughput. It's the standard equipment for larger, commercial-scale distillate production.
Uses a fractionating column to separate compounds step-wise by boiling point, collecting different fractions as the temperature climbs. It's less common as a standalone method in cannabis processing today but the underlying principle — separating a mixture into fractions rather than one single pass — is baked into how both short path and wiped film systems are actually run.
Different from the others in that it's typically used to pull terpenes directly from fresh or frozen plant material rather than from an already-extracted oil — steam carries the volatile terpenes off the plant matter, then the terpene-laden steam is condensed and separated from the water. It's more common in essential-oil-style terpene production than in cannabinoid distillate processing.
| Short Path | Wiped Film | |
|---|---|---|
| Process type | Batch | Continuous |
| Material | Glass | Steel |
| Thermal exposure | Longer per batch | Very short (thin film, brief pass) |
| Typical scale | Smaller / craft | Commercial |
| Throughput | Lower | Higher |
There are two general approaches to getting flavorful terpenes into a final product: capture the plant's own terpenes during the distillation pass and preserve or reintroduce them into the finished distillate, or add terpenes back in afterward — either strain-specific terpenes recovered from the same batch, or a terpene blend formulated to hit a certain flavor profile. Both approaches are widely used across the industry; which one a given product uses is part of what separates otherwise similar-sounding extraction types from each other.
All of this happens at a licensed processing facility using purpose-built vacuum, glass, and steel equipment — not something assembled at home. Regardless of which distillation method or equipment a processor uses, the finished product sold in Washington or Oregon still has to pass the same state-mandated lab testing — potency, residual solvents, pesticides, heavy metals, and microbials — before it's allowed on a dispensary shelf.