Glossary of co2 extraction process

The following glossary of terms is definitions used throughout the CO2 for botanical extraction industry.


The process of changing a vapor or gas into a liquid. The liquid in this case is called condensate. The term thin film is also applied to a condenser because as condensable vapor gas encounters a cold condenser, a thin condensate film will form automatically. Careful engineering of the condensation path is a key aspect of the overall distillation process. The thin condensate film is typically removed by gravity.

Condensers are typically situated in two positions relative to the evaporator. The first position is in close proximity to the evaporator. This is called a short path. In the second position, the condenser equipment is located remote from the evaporator.


Refers to the thermal process of evaporation of a volatile from a fluid and condensation of that volatile to produce a separation between the components that are not evaporated and the components that are condensed.

The evaporation of a liquid will produce gas. That gas then travels (called diffusion) to a condenser where it cools and condenses back to a liquid. This is typically accomplished under the power of a vacuum pump.

Distillation systems and distillation equipment

Typically incorporates both an evaporator and a condenser so as to provide a separation between the evaporated fluid and condensate.


A piece of equipment designed to remove selected volatile components from a fluid. Selectively removing solvents from fluids is accomplished by controlling the temperature and pressure of the fluid.


Evaporation refers to the thermal process of a liquid changing to a gas under pressure or thermal influence. This change is also known as a “phase change”. This happens when water boils and makes water vapor. In the case of cannabis processing, evaporation refers to two different processes. First, a phase change of cannabinoids like CBD from the liquid state evaporates to a gas at a high temperature and vacuum. This change happens at the evaporator surface. Second, evaporation refers to the phase change of a solvent such as ethanol as it is being removed from the oil. An evaporator typically has an external condenser.

Evaporator equipment is typically designed to produce a thin film on a heated surface so that solvents will volatilize quickly and efficiently.

Falling Film

The falling film refers to a film that spreads over an evaporative surface by gravity. The fluid, in this case, must have low viscosity at the evaporator temperature so that it can flow and evaporate.

Fractional Distillation

Fractional Distillation refers to the ability to start distilling at a low temperature and ramp up the temperature to sequentially boil the components. The components are also sequentially condensed thus allowing separate fractions to be collected.

Molecular Distillation

Molecular distillation refers to distillation under high vacuum pressure that reduces the probability or frequency of one evaporated molecule encountering another. Under a high vacuum, evaporation of cannabinoids from oil purportedly migrates unimpeded from the evaporator to the condenser. However, the conditions for true molecular distillation do not occur in the case of cannabis or hemp oils as there are always other compounds that co-distill with the cannabinoids.

Rotary Evaporators (Rotovaps)

Maybe the most common way to accomplish solvent removal in the hemp and cannabis industries. A form of short path distillation equipment using a spinning round bottom flask, a vacuum pump, a heating bath, and a chilled condenser, to evaporate and collect volatile fluids into a receiving flask.


Short-Path refers to the distance that the evaporated liquid-vapor travels from the evaporation surface to reach the condenser. In practice, a “short path” describes the location of the condenser in relation to the evaporator. The short path has an internal condenser whereas an evaporator has an external condenser.


Still refers to an apparatus where distillation (evaporation and condensation) are taking place independent of whether the still is a short path, falling film, molecular, or wiped film.

Thin Film

The process of coating the solution to be evaporated into a thin film on a heated surface. Wiped film apparatus used in hemp and cannabis distillation are not usually fixed distance but typically use “comb” shaped wipers to mix the oil on the surface of the oil while simultaneously creating a thin film at the surface. A thin film is important so efficient evaporation can occur.

Thin Film also applies to a condenser because as condensable vapor gas encounters a cold condenser, a thin condensate film will form automatically and is typically removed by gravity.

Wiped Film

The wiped film refers to the existence of a wiper to wipe a fluid over a hot evaporation surface. Wiped film evaporation refers to evaporation from the hot surface as the wiper creates a thin film on the evaporation surface.