Serious concentrate connoisseurs have likely heard of color remediation column technology (CRC) before, especially if they prefer BHOs, but many newer cannabis consumers have likely never heard of CRC. Simply put, CRC is a technology that allows concentrate and extract makers to remove unwanted colors and impurities from their products, resulting in a very light color or golden extract, that many view as more attractive. As with all new technologies, the use of CRC has not come without controversy and concerns.
The History of CRC
The exact origins of CRC are not clear but the earliest many industry professionals report hearing about it was in 2016, though it’s possible it was used in the unregulated market for longer before making the jump to the regulated cannabis market. What is clear is that by 2017, CRC had gone mainstream and was widely being used across the United States.
What is CRC?
At its core, CRC uses a vertical column, often made of stainless steel, which is then packed full of various filtration media – generally a mix of bentonite clay and silica gel for doing simple color remediation. The goal is to turn concentrates and extracts perceived as being low-grade due to a darker color into ones that are lighter in color and thus seen as more desirable. The darker color in concentrates and extracts generally comes from chlorophyll or other contaminants which can be removed by using CRC.
In addition to the bentonite clay and silica gel used for simple color remediation, extract and concentrate makers can also use activated charcoal, diatomaceous earth, Magnesol, and other media. CRC can be done as one single step or as multiple steps and it isn’t just one uniform technology, it is a range of post-extraction processing techniques that is constantly evolving.
While “color” is in the name, it is possible to use different blends of filtration media in CRC to remove more than just color, such as residual solvents, pesticides, off-flavors, and even “byproducts produced from processes such as converting CBD or ∆9 into ∆8-THC synthetically.”
CRC is Ubiquitous But Unknown
Given the vast number of impurities and contaminants that CRC can filter out, it is no surprise that CRC is very widely used around the U.S., but it isn’t generally disclosed to consumers, or to dispensary staff during brand-run training sessions. Some sources estimate that over 90% of the U.S. extract and concentrate market are already using CRC and those same sources have observed companies being unwilling to stop using it.
Is CRC Safe?
At present, there is no research showing that CRC filtration media can end up in finished products or any showing confirmed harms of using CRC technology. That means the main drawback is that CRC may unintentionally remove terpenes that are desirable as well as undesirable ones. Depending on which extract is being made, such as a distillate, that drawback is irrelevant because distillates already are terpene-free and have terpenes reintroduced after distillation. Additionally, there is no established testing methodology to confirm the use of CRC.
What there is research on is the health impacts of mining bentonite clay and diatomaceous earth, but that is not a good parallel as those miners, some of which experienced respiratory damage, breathed in a lot of contaminated dust for many years. It also is important to note that while some filtration materials like bentonite clay are designated by the FDA as Generally Recognized As Safe (GRAS), that only applies to its use in food, not inhaled products. Furthermore, the FDA has issued warnings about specific brands of bentonite clay which had elevated levels of heavy metals. Thankfully, most legal cannabis markets have very strict regulations around lab testing for contaminants, which would catch any heavy metals that managed to get into the finished product. There also are techniques that can be used by the concentrate and extract makers to filter out the filter media itself, such as running it through a .45 micron screen (like those used for making bubble hash or kief).
At the end of the day, CRC is just another tool in the remediation tool box, which can be used to improve product quality and safety, but can also be misused to remove beneficial natural terpenes. If the product passes the required safety testing, which for cannabis products is generally stricter than for any food product we ingest on a daily basis, then that product is safe for consumption.
How to Spot CRC
Unlike Clean Green, Dragonfly Earth Medicine, Sun+Earth Certified, Organically-Grown, and all the many other certifications out there for organic or sustainable cannabis, there is no certification at present to ensure your concentrate or extract was made ‘Certified CRC-Free.’ The best things consumers can do in the meantime is to contact brands directly to ask them or ask their budtender (though the budtender is less likely to know than the brand themselves). Much of the controversy over CRC’s use has to do with the fact that it isn’t disclosed to consumers, so to some people critical of CRC, it feels a little bit like fraud.
There are some things that consumers can look and smell for that may indicate the use of CRC, though these techniques cannot confirm the use of CRC. Visual cues include a uniform white or light color (white for concentrates like bubble hash or a light gold color for BHOs), which is unlikely to be reached through normal means without the use of CRC. Given that CRC generally does pull out some or all of the natural terpenes, many operators replace them with terpenes that aren’t from cannabis, often citrus terpenes. In other cases, if there is too much color remediation material used, the flavor can end up tasting of chemicals.