Cryogenic vs. Cold Ethanol Extraction
Is ‘Cold’ Ethanol Extraction the same as ‘Cryogenic’ Ethanol Extraction?
In the cannabis extraction industry knowing the true definition of technical and scientific terms is critical to ensure a successful result. When it comes to the chilled ethanol extraction process you may have heard the term “cryogenic extraction” used quite frequently to describe what is simply—and technically—simply cold ethanol extraction.
As you may know, when extracting cannabinoids using ethanol, one of the critical factors at play is temperature. Too warm and you run the risk of undesirable compounds being released. Too cold and your efficiency and profitability may be reduced significantly. For these reasons cold ethanol extraction is often the preferable method with an optimal temperature range ideally between -30˚C (-22˚F) and -40˚C (-40˚F).
Note, ethanol extraction of cannabinoids may also be performed at ambient or room temperature. But you’ll need to perform additional post-processing steps to ensure a similar result incurring extra time and cost. This is the core reason why we chill ethanol before extraction. Learn more about the differences between cold vs. room temperature extraction.
What is the correct definition of cryogenic ethanol extraction?
Today, the term ‘cryogenic ethanol extraction’ has widespread colloquial use in the cannabis industry when people are, in fact, referring to cold extraction. The reasons for this misnomer are lost in the mists of time but the term ‘cryogenic’ refers to temperatures much lower than those we would use for cold or room temperature extraction.
The term cryogenic refers to temperatures between -153°C (-243.4°F) and absolute zero or -273°C (-523.4°F). These extremely low temperatures are too cold for ethanol extraction because ethanol’s freezing point is at -114.1°C (-173.5°F) rendering it obviously useless as an extraction solvent.
In fact, a universal definition of the term “cryogenic” or “cryogenics” is defined as a threshold of 120 K (or –153 °C) to distinguish these terms from the conventional refrigeration temperatures. Learn more about the correct definition of Cryogenics here.
Are cryogenic temperatures used in other ways for cannabis or hemp processing?
Yes, cryogenic temperatures are used in cannabis and hemp processing but not in the context of ethanol extraction. One way that modern-day large scale hemp extractors are using cryogenic systems is by the use of nitrogen tunnel-freezing technology to “flash freeze” freshly harvested hemp to retain the plant’s sensitive cannabinoid compounds such as terpenes and CBD potency. Cryogenic freezing also protects the plant from molds and other contaminants introduced by the traditional time-consuming curing process.
Cryogenic freezing delivers increased speed of processing and standardized, controlled cooling. The ability to use a consistent, repeatable temperature ensures quality and repeatable processes that help meet compliance requirements for Good Manufacturing Practice (GMP) and other standards. Cryogenic freezing may be applied to a large part of the hemp value chain, from harvesting to processing to packaging.