If you’ve been paying attention to cannabis at all over the past decade, you’ve probably noticed some new players to the game: concentrates. Although some forms of solventless concentrates, such as hash and kief, have been around for centuries, a whole new category of concentrates with a whole new degree of potency has arrived. In this article, we’re going to explore what distinguishes these new varieties of concentrate from their older relatives and why they necessitate testing more than similar products.

What is a Concentrate?

Concentrates are any cannabis products which utilize the targeted extraction of THC or other cannabinoids in order to achieve a higher degree of potency than otherwise possible. While normal cannabis flower might have a potency (or total cannabinoid content) ranging from 5%-30%, concentrates can have potencies ranging from 30% to 95% or even higher. This means that an average consumer will require much less material to achieve the same effects. Not only that, but concentrates are also much more often consumed through vaporization rather than combustion, so their “smoke” can tend towards having fewer harmful hydrocarbons, plant material, and other harmful toxicants (although, it should be said, you can also vaporize flower or smoke concentrates). Some users prefer to ingest edibles as opposed to smoking flower or vaping concentrates. 

So, concentrates are basically super weed. They’re not all the same, however. One big, important distinction is between solventless concentrates and those which utilize solvents. A solvent, if you’ll remember from high school chemistry, is any compound which other compounds readily dissolve into, forming a solution. This famously includes alcohol, a stellar solvent, but also technically includes water – which, while an excellent, natural, harmless solvent, is typically excluded from the list of “cannabis solvents” considering how common and harmless it is. More commonly listed as cannabis solvents are hydrocarbons such as butane, propane, pentane, and hexane as well as similarly effective solvents such as acetone and other ketones.

If you read that and immediately had a guttural reaction to the idea of smoking acetone, you’re not alone. Residual Solvent Testing, or RST, is perhaps the singularly most important metric for most concentrate consumers. That being said, it’s certainly not the only one. Let’s break down what different compounds, chemicals, residuals, and toxicants that are typically tested for in concentrates and why it’s important to test for them.

Residual Solvent Testing

As mentioned before, there are plenty of unsavoury solvents that get used to extract cannabinoids and craft concentrates. That being said, a major factor of concentrate extraction is to remove or reclaim that solvent. While different states require different degrees of testing and have different variances allowed for solvents, results are generally returned in the range of PPM or PPB – parts per million or parts per billion. If the extraction was successful, there will be levels of solvents that are nearly undetectable, or are even comparable to levels found in natural atmosphere. Not only this, but hydrocarbons are consumed when vaporized – that is, they’re converted from long chains of hydrogen and carbon into two different compounds, H2O (water) and CO2 (carbon dioxide). We all know H2O is harmless, but CO2 can be harmful when inhaled in large amounts. This is all a number games, however: you’re much more likely to inhale relevant amounts of CO2 when driving in dense traffic or when using aerosolized hairspray than when dealing with something under 400 PPM.

Solventless concentrates avoid this problem entirely, by achieving their concentration of cannabinoids through mechanical or physical means rather than chemical. However, this still leaves them exposed to other toxicants, such as pesticides and fungicides which require their own testing.

Pesticide Testing

Pesticides, as the name suggests, are compounds which kill pests. They can be natural, like some essential oils, or synthetic, like ammonium nitrate. There are pesticides which work chemically, like poisoning bugs, and there are pesticides which work mechanically, like gluing them down and keeping them from reproducing. As a result of this, there are certainly some pesticides which are more harmful for humans than others – anything that poisons bugs might also poison you and I. However, it’s always a good idea to test for any sort of pesticide rather than assume some are harmless, which is why pesticide testing will generally cast a wide net.

Pesticides are widely used in the cultivation process for cannabis, and cannabis plants will generally undergo a process of “flushing” before being harvested, dried, and cured in order to remove as many residual pesticides as possible. On top of this, many cannabis cultivars who use pesticides will only use pesticides which are approved for food use – the same pesticides which might be applied to apples, or berries, or leafy greens. That being said, it should be remembered that all chemicals – all pesticides, including organic ones which occur naturally – have the potential to be hazardous.

There’s a famous phrase, which rings as true in this case as in all others, that the “dosage makes the poison”. Even the most toxic compounds are harmless if the exposure is low enough, and even the slightest toxicity can be lethal if exposure is high enough. Rather than push that line, though, of limiting your exposure to just below a harmful amount, the wisest course of action is probably to limit your exposure to harmful compounds as much as possible.


Heavy Metal Testing

Just like municipal water testing or food testing, cannabis is often tested for heavy metals. Heavy metals are a class of elements which are forbiddingly difficult for the body to naturally process and remove, leading to accumulation and growing toxicity. There are four heavy metals which are typically given the most attention due to their higher risk of exposure: cadmium, arsenic, lead, and mercury.

Over the past several years, California has begun phasing in testing regulations and requirements for heavy metal content. The requirements in California are all under one microgram of contaminant per gram of cannabis, or one part per million. In order to keep cannabis products under this level, cultivars are encouraged to use thoroughly purified water, as well as sophisticated and specialized growth media. Water with high levels of heavy metals and erosion of growth media are the two primary vectors which heavy metals arrive through.

While heavy metal testing is important for cannabis, it’s even more so for concentrates: cannabinoids aren’t the only compounds which are concentrated through the extraction process. Terpenes can also grow more potent, as can toxicants and contaminants. When you’re turning 10 grams of material into 1 gram of material, every other compound you’re working with is becoming proportionally larger.

Microbial Content

While pesticides and fungicides might poison you, and heavy metals might accumulate in your body, microbial content involves small living organisms which can make you sick. This is especially dangerous to medicinal cannabis patients, who may have weakened immune systems or may not be able to use traditional antibiotics. Cannabis plants, like many plants, can serve as effective habitats for microorganisms like E. coli, aspergillus, salmonella, and other harmful bacteria that can constitute major health risks.

While pesticides are knowingly applied to plants, and heavy metals are easily controlled through water intake and growth media, microbial content can arrive through somewhat more discreet means. Some can be transported through cross-contamination, which food service workers will be intimately aware of. You go out, touch a few doorknobs, eat a little sushi, then go and tend to your plants. Without washing your hands along the way, it’s as if you rubbed that material directly on the cannabis itself. By taking something already contaminated, and connecting that contamination with your cannabis through a series of unsanitary interactions, you can end up with some seriously hazardous material.

Not only that, but microorganisms are all around us on a daily basis. Spores from molds or fungus can transport through the air, and the release of spores is often the most prominent during summer and early fall, which happens to be almost exactly the same as the cannabis growing season, leaving outdoor crops especially vulnerable.

These vectors are all able to be controlled for, thankfully. Rigorous sanitation requirements for the cultivars and processors can largely eliminate the threat of cross-contamination, and modern air filters for ventilating indoor crops can remove the threat of airborne microorganisms. Outdoor crops may need to rely on the use of fungicides if they’re in a particularly moldy area, or simply account for the potential of lost crops when planning their grows. Thankfully, as discussed above, there are methods for controlling the risks associated with fungicides, such as finding formulations specially designed for human consumption.

The Final Word on Concentrate Testing

At the end of the day, testing is what keeps your favorite medicinal and recreational dispensaries open. Across Los Angeles, a sophisticated network of growers, testing facilities, manufacturers, and processors work hard to ensure their products are safe and effective. Every year, their methods become more accurate and reliable.

Concentrates, however, are an area where this network cannot afford to make mistakes. When you’re working with volatile, poisonous solvents, toxic pest control, heavy metals, and microorganisms, the very concept of “concentrating” becomes a tightrope walk. That’s why it’s so important to test our concentrates and ensure we understand what to test for and the negative consequences of failing to do so. At Sweet Flower in Melrose, Studio City, and  we ensure every part of our supply chain is properly licensed, certified, and follows relevant state regulations when it comes to health and safety. That’s how we keep cannabis safe. Stop by our Arts District DTLA dispensary or order cannabis delivery online from our Melrose or Studio City locations.