Decarboxylation is an important aspect of cannabis and hemp processing that is often discussed but not always entirely understood. From a chemical perspective, decarboxylation removes a carboxyl ring from the cannabinoids found within raw plant material and releases carbon dioxide as a result. Raw plant matter contains the acidic forms of common cannabinoids, seen as CBDA and THCA
In order for these compounds to be readily available to bind with receptors in the endocannabinoid system, these acids must be removed. This occurs through decarboxylating them – removing the carboxyl ring and converting them into active forms of CBD, THC, and other cannabinoids. The active forms of these compounds (those that have had their carboxylring removed) possess the majority of medicinal and other benefits which make hemp and cannabis so sought after.
Decarboxylation occurs through either exposing plant material to heat or light. Natural aging and UV light creates slight decarboxylation while heat is the most common method used by producers and processors to make viable end products. Methods for decarbing flower can vary from simple at-home techniques (smoking being the most obvious) to large-scale procedures that are an integral aspect to many successful extraction operations. Even though these processes can be different, the aim of them all is to create better products for consumers.
All of the science aside, there are choices to make from a production standpoint for when it is best to decarboxylate plant material during the extraction process. Decarboxylation prior to extraction is common and has some definite advantages over post-extraction. One advantage is the conversion of THCA and CBDA to THC and CBD before extraction. This makes oil extractions psychoactive (for THC) and activates medicinal and other desired benefits (for CBD and THC).
Another advantage is that heating plant matter before extraction will remove moisture content. Higher moisture content can directly lead to lower extraction yields as water can interact with solvents present in the process, leading to a potential slowdown and impacting overall efficiency. THC is more soluble than THCA as well which, specifically in CO2 extraction methods. This means that the process can be considerably faster which directly translates into larger yields. Soluble cannabinoids combined with non-polar solvents can create these higher yields as waxes can melt into them through the heating processes that occur prior to and during extraction.
There are also a few downsides to pre-extraction decarboxylation, even though it does have the considerable benefits mentioned above. High levels of heat can lead to a loss of some important and desirable properties to both cannabinoids and terpenes and result in a less potent and effective extraction. In an ideal decarboxylating situation, the minimum amount of heat should be used over an extended time period in order to preserve the potency and effectiveness of desirable compounds. A temperature of around 220F (105C) for around 30-45 minutes is ideal for THC focused extracts while hemp flower used for high CBD extracts can withstand somewhat higher temperatures for longer periods of time. Terpene preservation is also a consideration with pre-extraction decarboxylation and excess heat can cause these compounds to burn. Terpenes are key flavor and profile compounds that can give an extract unique characteristics that can easily be compromised if burnt. It is ideal to keep temperatures in the same range as mentioned above and always under 300F in order to best preserve terpenes.
Even though there are obvious advantages to pre-extraction decarboxylation, implementing the process post-extraction is another viable option. If THCA is desired out of an extract for any medicinal or non-psychoactive purposes, decarbing post-extract will preserve this compound. THCA is also needed when making shatter – an in-demand extraction product that is popular among many consumers. Also, by not heating plant material prior to extraction, more terpenes can be preserved which can allow for a more desirable color or flavor of the finished extraction. This loss of characteristics can be nominal and unimportant to some extractors but if appearance and taste is important to a production, post-extraction decarbing is worth considering. However, in contrast to pre-extraction, decarboxylation afterward will lead to lower overall yields and longer extraction times.
Decarboxylation is a necessary step in the extraction process. The decision of whether to implement the process prior to or after extraction is a decision left up to individual operations with each having different benefits and drawbacks. Pre-extraction decarbing is a more common practice overall due to the higher yields and faster extraction times it provides but post-extraction has its place for certain purposes and desired end results. Regardless of which route is preferred, attention must be given to the decarboxylation process to ensure ideal temperatures are maintained to produce the highest quality extraction possible.