Concentrates
Solvent-Based Cannabis Extraction: A Deep Dive
When it comes to cannabis extraction, we're talking about the magic of turning raw plant material into something more potent, more concentrated—something with power. And, just like a master chef knows how to coax out the essence of a dish, extraction artists use solvents to draw out cannabinoids and terpenes, leaving behind the undesirable bits. Let's take a closer look at the key solvents in the cannabis industry, how they work, and what they leave behind.
1. Butane (BHO): The Heavyweight Champion
Butane Hash Oil (BHO) extraction is the rockstar of the cannabis concentrate world. It’s fast, effective, and can create a vast array of textures. The process involves soaking the cannabis in butane, which dissolves the cannabinoids and terpenes. Once the extraction is done, the butane is purged, and what's left is a concentrated product—sometimes shatter, sometimes wax, sometimes live resin.
Molecular Action: Butane’s non-polar nature means it targets cannabinoids and terpenes while leaving water-soluble compounds like chlorophyll behind. That’s why BHO extractions have a cleaner, smoother taste.
Common Equipment: Closed-loop systems, vacuum ovens, and butane recovery pumps. Closed-loop systems ensure that no volatile butane escapes into the environment—a crucial safety precaution when working with such flammable solvents.
Resulting Textures: Shatter, with its glassy, brittle form, or budder, wax, and even live resin, depending on how the post-extraction process is managed. Temperature and whipping methods can alter the final consistency, creating everything from gooey to solid textures.
2. Propane (PHO): The Terpene Savior
Propane Hash Oil (PHO) is like the little sibling to butane, but don’t be fooled—it has its strengths. Propane has a lower boiling point, which means it’s better at preserving volatile terpenes, those delicate compounds responsible for aroma and flavor. If you’re after a concentrate that packs a powerful terpene punch, propane might be your go-to.
Molecular Action: The lower boiling point of propane allows it to extract terpenes more gently, meaning less degradation and more complex flavor profiles in the final product.
Common Equipment: Closed-loop systems, similar to those used in BHO extractions, but optimized for propane’s lower boiling point.
Resulting Textures: Budder and sugar wax are common with PHO due to its ability to retain higher terpene levels, which lend themselves to softer, stickier textures.
3. Ethanol: The Workhorse
Ethanol extraction is the workhorse of large-scale cannabis production. It’s versatile, efficient, and capable of extracting cannabinoids and terpenes from even the most stubborn plant material. However, its polar nature means it also extracts less desirable compounds, like chlorophyll, which can give the final product a harsher taste unless properly filtered.
Molecular Action: Ethanol’s polar nature means it’s excellent at pulling out a wide range of cannabinoids and terpenes, but it also grabs onto water-soluble compounds like chlorophyll. This can require post-extraction filtration to clean up the extract.
Common Equipment: Rotary evaporators, cryogenic freezers (for cold extraction), and various filtration systems are key players in ethanol extraction. Cold ethanol extraction can minimize the extraction of unwanted compounds, resulting in cleaner concentrates.
Resulting Textures: Oils, tinctures, and distillates are the most common products of ethanol extraction. Ethanol excels in large-scale production, producing clean distillates for edibles, vape cartridges, and tinctures.
4. CO2 (Supercritical CO2): The Scientist’s Choice
Supercritical CO2 extraction is where science meets cannabis. This method uses carbon dioxide under high pressure and temperature to extract cannabinoids and terpenes. It’s one of the cleanest methods because CO2 leaves no harmful residue. The process is highly tunable, meaning extraction artists can manipulate temperature and pressure to isolate specific compounds.
Molecular Action: Supercritical CO2 exists in a state that’s neither purely liquid nor gas, allowing it to dissolve cannabinoids and terpenes efficiently. It also doesn’t leave any harmful residues behind, making it a popular choice for health-conscious consumers.
Common Equipment: Supercritical CO2 extractors, which maintain the high pressure and temperature required to keep CO2 in its supercritical state. Separators are used to isolate cannabinoids, terpenes, and other compounds during the process.
Resulting Textures: CO2 extraction is used to create oils, vape cartridges, distillates, and other highly tunable products. The ability to fine-tune temperature and pressure means producers can target specific compounds, resulting in a highly customizable concentrate.
Common Extraction Equipment
Closed-Loop Extraction Systems:
These systems are the workhorses of the cannabis extraction world, handling volatile solvents like butane or propane with precision and safety. In a closed-loop system, no gas escapes into the environment. The solvent passes through cannabis, dissolving the cannabinoids and terpenes, before being recovered and reused in the next cycle. It's a zero-waste, high-reward operation.
How It Works: Imagine running a loop where the solvent moves through plant material, extracts all the good stuff (cannabinoids, terpenes), and is then recollected, purified, and ready for the next run. The entire process takes place in a contained system to prevent explosions and leaks.
Safety Precautions: The name of the game is safety—explosion-proof equipment, continuous gas-leak monitoring, and industrial-grade ventilation. Equipment must meet ASME (American Society of Mechanical Engineers) standards for high-pressure safety. Properly trained operators and regular maintenance checks are essential to ensure no solvent mishaps.
Licensing/Training: It’s not something you can jump into with a day’s training. Operating a closed-loop system requires certification in flammable gas handling, extraction processes, and complying with stringent state regulations.
Rotary Evaporators:
The rotary evaporator is the elegant, meticulous workhorse for ethanol extraction. After the cannabinoids and terpenes are extracted from the cannabis using ethanol, a rotary evaporator gently evaporates the solvent, leaving a clean concentrate behind.
How It Works: It operates using heat and vacuum pressure. As the flask spins, it maximizes surface area, allowing the ethanol to evaporate more efficiently. The vacuum helps avoid overheating the product, preserving the integrity of cannabinoids and terpenes.
Safety Precautions: Glass components must be handled carefully to prevent implosions. Adequate ventilation is crucial for safely evaporating solvents like ethanol, and the evaporator itself must be checked regularly for leaks or pressure malfunctions.
Licensing/Training: Operators need certification in solvent handling, knowledge of lab safety protocols, and training in rotary evaporation techniques. The equipment might look simple, but its precision is critical.
Vacuum Ovens:
Vacuum ovens take the concept of purging to a scientific level. After solvents like butane or propane are used in extraction, the vacuum oven removes any residual solvents by applying low pressure, allowing for evaporation without the need for excessive heat.
How It Works: By lowering the pressure inside the oven, the boiling points of solvents drop, allowing them to evaporate at lower temperatures. This prevents degradation of sensitive cannabinoids and terpenes, resulting in a pure, potent final product.
Safety Precautions: These ovens need to be explosion-proof because residual solvents can be flammable. Proper ventilation is necessary, along with regular checks for leaks. Operators also need to monitor the vacuum and temperature to ensure there are no mishaps.
Licensing/Training: Certification in operating vacuum systems and flammable solvent handling is a must. Knowledge of the intricacies of vacuum purging is vital to avoid product degradation.
Supercritical CO2 Extractors:
Supercritical CO2 extraction is the eco-friendly option for cannabis concentrates. This method utilizes CO2 at a supercritical state—where it’s neither a gas nor a liquid—to dissolve cannabinoids and terpenes without harmful residues.
How It Works: CO2 is pressurized to around 1,100 psi and heated to temperatures over 87°F, turning it into a supercritical fluid. This allows it to pass through the cannabis, dissolving cannabinoids and terpenes. The result is a clean, tunable extract—ideal for everything from oils to vape cartridges.
Safety Precautions: High-pressure systems are no joke. The equipment must meet ASME standards to withstand the pressure, and operators must monitor pressure and temperature precisely. Any leaks or system failures could lead to dangerous conditions.
Licensing/Training: Extensive training in handling high-pressure equipment and CO2 safety protocols is required. This isn’t something you can just figure out; it demands expert knowledge and certifications.
ASME Standards: What are they?
The American Society of Mechanical Engineers (ASME) sets the bar for pressure vessel and equipment safety, ensuring that systems can withstand the rigors of high-pressure applications. In the world of cannabis extraction, meeting ASME standards is not just recommended—it’s mandatory for safety. Whether you’re working with butane, propane, or CO2, your equipment must be able to handle the pressure—literally. If a piece of equipment fails to meet ASME standards, the risk of explosion or mechanical failure increases exponentially.
A Final Word on Solvent-Based Extraction
Each of these methods—whether it’s butane, propane, ethanol, or CO2—brings something unique to the table. The choice of solvent affects not only the flavor and potency of the final product but also the texture, consistency, and overall experience. BHO may produce that shatter we all know and love, while PHO offers those soft, flavorful budders. Ethanol is the unsung hero behind distillates, and CO2 stands out for its clean, customizable extracts.
It’s not just about cannabinoids; it’s about preserving the plant’s essence, capturing the terpenes, and ensuring the pure