Access to medical and recreational marijuana has become more widespread, and dabs are quickly becoming many people's preferred way of consuming cannabis. There are a lot of reasons why this is the case. To dab, you drop a small amount of concentrate onto a heated piece of metal called a nail that is connected to a smoking device called a rig, which is similar to a bong. The effects of consuming a very small amount of concentrate this way are considerably greater than consuming a similar amount of flower. This can be beneficial for many reasons, both medical and recreational. Dabbing also doesn't require a smelly ashtray, and it is possible to find all sorts of electric powered devices these days that take away the need for a torch to heat the nail. Concentrates can be used in other ways as well, such as dropped on top of flower in a pipe, or loaded into some vaporizer pens.
I wanted to get a better understanding of how the concentrates I use are made, so recently I watched some friends of mine at Extractebles make BHO. The extraction method they use is a closed loop system (CLS) made by Iron Fist Extractors that is certified for use in Colorado, Washington, and Oregon. BHO is made using a mixture of N-butane and propane. Some have expressed concern about using these gases for cannabis extraction, but they are available at very high purities and are evaporated from the concentrate during the process. Certain cooking oils are extracted using hexane, a similar solvent, which is also removed before those oils are consumed. Leftover solvent testing performed in labs also prevents improperly processed concentrates from entering medical dispensaries, one of the benefits of a legal, regulated marijuana market. I watched the Extractebles team run some Grapefruit and Jilly Bean material that I brought them, and it was fascinating to see the process that goes into making shatter.
Before the extraction process can begin, any closed loop system must be carefully inspected for safety. The Extractebles team take precautions at every step to ensure there are no vapors escaping through any breaches or leaks in the gaskets. Each bolt on the machine is tightened with a torque wrench in order to ensure all the pieces are securely attached. While running the solvent through the machine they also sprayed different areas with a squirt bottle to watch for bubbling, which would be a sign of a leak. As a precautionary measure there was also a combination of explosion-proof fans throughout the area to vent any vapor that may escape off the floor, and out the windows.
Some people use flower to make their concentrates, I use the trichome covered leaves that are trimmed off the buds for mine. Either way, there can be no residual moisture in the product when it is extracted in a closed loop system, or the solvent will freeze to the water and lock up the machine. I make sure the cannabis is dry enough that any stems snap, and the leaves are crunchy. The material is placed in a stainless steel cylinder called a spool and kept in a freezer at 0º Fahrenheit prior to being run through the extraction machine. The cold temperature traps lipids and fats within the plant matter, while the cannabinoid and terpene rich trichomes stay mobile.
To start the extraction process, the spool full of cannabis is attached to the Iron Fist machine. Then, a vacuum pump is used to depressurize the hose running from the solvent storage tank to the system. This process is done to remove any air from the line. Next, the valve is opened to release the solvent and the liquid is pulled into the spool. At this point, the cannabis material is left to soak for a brief period. Different extractors will soak the material for varying amounts of time, which partly determines the yield. The longer the solvent soaks in the material, the more cannabinoids and terpenes you will pull out, but if you leave it too long you also start to pull out fats and lipids, which you do not want. After this short soak, the valve at the bottom of the spool is opened, dumping the concentrated material through a filter and down into the collection vessel at the bottom. The collection vessel is in a tank of warm water in order to evaporate some of the solvent into vapor. An explosion proof pump is then used to draw the vapors from the collection pot through a cooling coil that brings the recaptured gas back to a liquid form, and returns it to the storage tank where it began. Hence the name "closed loop system".
The material left in the collection chamber after the evaporated solvent is pumped through is poured onto parchment paper, and placed into a carefully controlled vacuum oven. Immediately upon placing the mixture into the oven it bubbles up, which is when a lot of the solvent is being evaporated. During the last stage of the process, the leftover solvent will be evaporated off in the vacuum oven. Cannabinoids and terpenes are also volatilized at specific temperatures and pressure combinations, so variation in the oven conditions can affect the end flavor and potency of the concentrate. Extractors will set their ovens to different temperatures and leave the material in for varying amounts of time according to what they believe are the best conditions. At Extractebles, the material is left in the oven for approximately 100 hours at a little higher than 90º F and the slab is flipped regularly. When the slab is removed from the oven at the end you are left with the concentrated THC, CBD, and terpene rich material to enjoy. You can find shatter made by Extractebles at Nectar Cannabis in Portland, when it is in stock, and soon to be in more dispensaries.
Thanks to the team at Extractebles for the tutorial, the team at Cascade Botanical for the technical help, and Iron Fist Extractors for the use of their photo.
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Find Cascade Botanical on their website
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