This brings us to the topic of BHO finishes and postprocessing. The most important things about a finish are the smell and taste (terpene preservation), and visual appeal. The last one centers largely on color with a preference for lighter yellows to clear. There are many tricks to getting light colors, starting with running only the best quality biomass, running it fresh, even uncured and frozen, as well as recent postprocessing innovations such as color remediation filtration and chromatography (an entire topic in itself). Much like making candy, BHO extraction is an art and a science; just as many forms of candy are made with sugar, water, and flavorings, there are many types of dabbable BHO products.

Back in the early days of the industry, circa 2013-2015, there was a famous saying: “if it doesn’t shatter, it doesn’t matter.” This has largely gone by the wayside, with various products available for dabbing and vaping that are made from BHO. Shatter is a clear, shiny, amorphous solid like glass, that’s finished in thin sheets in a vacuum oven. Like glass, it will both shatter when struck, or bend and flow slowly when warmed. The relative brittleness versus tackiness is the characteristic referred to as stability. This glassy amorphous solid is a homogeneous matrix of tetrahydrocannabinolic acid (THCA) which gives it stability and retained terpenes (5-15% by weight). The more terpenes there are in the shatter, the more tacky or sappy it will be, but also more flavorful.

Extremely brittle shatter will have less taste, but plenty of high. Decarboxylated THC, which is a gold viscous oil, will also make shatter tacky. For this reason, and for terp preservation, the starting plant material should always be run fresh, sealed away from oxygen, and kept cold and in the dark until it is run (preferably in a freezer). Additionally, running a cold dewaxing technique will make the shatter clear and more stable, and prevent it from denaturing over time and becoming cloudy. Shatter is poured or spread out thin on parchment sheets and purged carefully under gentle heat in a vacuum oven to remove the residual solvent without volatilizing away the precious terps.

Sometime around 2015, the industry invented a new finish called sugar-wax. This was a great relief to extractors everywhere, as the shatter finish is often hard to achieve and maintain. Shatter tends to denature slowly if not kept cold, and the clarity turns cloudy and opaque. This is a process of nucleation and crystallization called sugaring. It produces a fascinating effect as the amorphous structure transforms into a crystalline lattice and the trapped terpenes are released, allowing them to flow and become more volatile. Originally, this was an extractor’s nightmare, as their precious shatter turned cloudy and the terps ran off the parchment. But some clever practitioners started encouraging the process, scraping the terpy/sugary mixture off the parchment, and putting it into jars for presentation and distribution. Pouring the extract

directly into shallow Pyrex pans instead of into thin sheets further encourages sugaring. The result is incredible flavor and terp preservation inside the sealed jars. We call this the Sugar Revolution, from 2015-2016.

The crystallization phenomenon that makes sugaring happen is called supersaturation.

When a solute is dissolved and the solution is evaporated, or its temperature is dropped (or both), the resulting concentration is too high to remain dissolved. The surplus solute is unstable in solution and will precipitate, or crash-out, as crystals. 

There is a strong analogy between BHO concentrates and honey. The latter is a mix of glucose and fructose dissolved in 5-20% water. This is a supersaturated solution and a supercooled liquid and will crystallize over time, or quickly if it gets cold. BHO concentrate is a similar, but nonpolar, version of this mixture, with THCA and CBDA solids supersaturated in 5-20% terpenes and residual butane. Over time the cannabinoids form crystals, separating from the terpenes, resulting in two fractions called Diamonds and Sauce. This innovation was discovered by many people independently, often accidentally. It’s easily encouraged by running fresh-frozen material as live resin. Freezing the biomass fresh prevents decarboxylation of THCA, and the most volatile terpenes are retained instead of being lost in the drying process. Running it cold (-40 to -60°C) keeps the frozen water out of solution, while dewaxing in-line. Decarbed THC and lipids in solution will interfere with crystal formation, so you want to run live resin fresh and cold to dewax it.

Live resin can show double or triple the terpene content in the final extract. Rather than pouring the concentrate into Pyrex pans or onto sheets, practitioners fill mason jars with the liquid extract or use specialized diamond miners to hold it under pressure. The crystals precipitate naturally, or as I am fond of saying, “The secret to making crystals is that crystals make themselves, if the conditions are right...”

Before shatter and sugar and live resin, there was Wax and Crumble. These BHO products were made by mechanically whipping the concentrate, adding air, and purging it, until it thickened. With the innovation of live resin came a whipped finish known as Batter, where the terp fraction is combined with THCA crystals and whipped to make it fluffy, homogeneous, and wet. The high terpene content of live resin whipped batter leaves it wet and juicy instead of the dry texture of crumble. Batter is shelf-stable and won’t break down, and the wet juicy terpenes oozing out of it make an incredibly flavorful and aromatic product. Sugar-wax, diamonds and sauce, and batter finishes are all so rich in flavor and smell that I call them high-fidelity. These products smell just like the original flower they are extracted from but amplified. They are high-fidelity because they preserve and concentrate the terpenes that make the smell and flavor, without losing or denaturing them. This makes BHO live resin extracts some of the most expensive and valuable concentrate products on the market.

Many Products, Many Ways

In summation, there are many products that can be made with hydrocarbon solvents.

Finesse must be used to coax the molecules we want from the plant biomass and leave behind those we don’t. Ingenuity must be used to scale up production and efficiency. The finished products of hydrocarbon extraction are the most flavorful and sought after of all dabbable

products manufactured with solvents. With the three options of n-butane, isobutane, and propane, and various extraction techniques and finishing post-processes, the hydrocarbon extraction practitioner is as much a chef or an artist as a scientist.

© 2020,Boris Kogon

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