In the increasingly innovative cannabis extraction sector, a new method of filtration and purification is winning over the hearts and minds of BHO and ethanol extraction artists. A color remediation cartridge/column (CRC) is an additional column in a closed-loop extraction system that can be used for both hydrocarbon and ethanol extraction.
What Is CRC?
A CRC is a secondary filtration column containing various medias used to filter dark colors out of oils made with hydrocarbons or ethanol extraction systems. CRC equipment is usually attached between a material column and a collection container. The solvent-based concentrate is then pushed over filtration media that is capable of removing chlorophyll, lipids, xanthophyll, carotene, lycopene, pheophytins, and a variety of toxins.
Cannabis extraction companies can choose to pack their own color remediation cartridges with filter media. A range of adsorbent and absorbent powders and substances such as T5 clay, Magnesol, and silica are used to remove color and impurities in the concentrate.
The CRC process occurs after extraction and before solvent recovery to purify the final product. Below, you’ll find a list of common types of filtration media used in hydrocarbon and ethanol CRC additions and the compounds they target in the crude extract.
Activated silica gel has adsorbent and desiccant characteristics. Silica gel is commonly used to remove polar molecules from petroleum release sites. Activated silica gel can pick up chlorophyll, carotenoids, and other hydrophilic substances. Silica is crucial to removing the very darkest hues in an extract.
Activated carbon/charcoal is made up of microscopic holes and carbon atoms. A carbon molecule’s electrostatic attraction draws other molecules. Carbon filters are commonly used with activated silica gel to remove chlorophyll.
Activated bleaching earth or bentonite clay is used to decolorize a marijuana concentrate. These filter media are the final layer of filtration media that help remove the color when all other impurities have been removed.
Diatomaceous earth is a type of naturally-occurring, soft rock that has a light and powdery consistency. Diatomaceous earth provides extraction technicians with fine filtration.
Why Do Companies Use CRC?
Cannabis extraction companies are noticing the numerous benefits afforded by CRC and introducing CRC into the post-processing workflow. Cannabis companies are increasingly using CRC to remove waxes, lipids, pesticides, heavy metals, toxins, and compounds that give extracts a dark color.
Filtration media used in the CRC can produce a translucent and pure extract form with the highest levels of purity and potency. CRC technology also removes the pigments in the hemp or cannabis plant that has a harsh taste when inhaled.
What Are the Downsides of CRC?
While not the norm, some unscrupulous cannabis producers can run low-grade concentrate through a CRC system to try and polish the extract and lighten its dark hue to pass it off as high-grade dabs. Consumers none the wiser can be duped into buying less-than-ideal extracts. As a result, the extracts end up still tasting harsh and smelling horrible.
A unique ratio of different types of filtration media is used to filter specific compounds in a single run, preferably. Improper ratios and packing practices can cause clogging, channeling, and overall loss of product and improper filtration in the CRC. Undersaturation of the filtration media can reduce the overall cannabinoid content collected and reduce the overall yield, which can drastically affect revenue for a commercial operation.
Oversaturating the filtration media can force some impurities to go through the filtration levels and end up in the final product, which can be detrimental to human health. Inexperienced CRC operators can improperly stack and pack a CRC, which can risk contaminating the final product with any of the filtration materials.
For instance, activated carbon is usually made from coconut shells, wood, bamboo, and other carbonaceous materials. After a certain number of uses, activated carbon begins to break down and can release heavy metals from its ash content into the final extract. Activated carbon from natural sources can also release benzopyrenes, which are carcinogenic metabolites.
Another common issue when using CRCs is filtration and flow. Gravity alone won’t produce quality CRC filtration. Flow problems, clogging, and uneven distribution of media can convert an extractor’s high-quality extract into a low-cannabinoid and low-terpene distillate. The problem gets worse as manufacturers scale and the margin for error increases.
How to Counteract the Downsides?
When it comes to optimizing the CRC process, extraction technicians must carefully calculate ratios of the different materials being used. One of the easiest ways to determine how much filtration media to use is to test the biomass, first to determine the cannabinoid content and multiply the number by the weight of the marijuana material being processed.
For instance, a 10 pound run of extract (4480 grams) containing 12 percent cannabinoids would produce about 537 grams of concentrate. Extraction technicians must then use the estimated throughput to determine the percentage of media to use. The amount of media used also depends on the quality and freshness of the material.
In order to improve flow and filtration problems, extraction technicians must have the correct width of the filter column. Generally, a 10 pound run of extract would require a six-inch column. When volume doubles, operators can add a couple of inches to the filter width.
When channeling and improper filtration occurs, optimizing the packing process can help. Extraction technicians have had success using a hydraulic press on each media layer to make the material completely flat. Operators can also set the blowoff valve low enough to not cause too much back pressure and create channeling, albeit, the process does lower yield a bit.
The advantage of using BHO closed-loop extraction is that the extraction process collects more terpenes than most other solvent extractions. Because you start off with more terpenes when using hydrocarbon extraction, any minor terpene loss during color remediation won’t make a considerable difference in the final concentrate.
For those worried about mutagenic metabolites and heavy metals getting past the filters into the final extract, buy activated carbon filter sheets instead of loose carbon. The filter sheets are made with varying pore sizes and offer superior adsorptive features. High-quality activated charcoal can perform color adsorption, odor adsorption, color stripping, and decolorization without leeching onto the extract.
Polishing up BHO and ethanol concentrates with color remediation cartridges is a new and robust way to lighten the color, taste, and odor from a crude extract. Reducing color and odor, however, isn’t always the best choice for every strain.