In 2007, a patent was filed for delta-9 THC processing. It covered a range of organic solvents with boiling points preferably below 0C – ie “low boiling point solvents.” This fits the description of several hydrocarbons – the author preferred isobutylene, propane, butane, and cyclobutane.

This patent was validated with very pure THC – from 95-99% – nearly reagent grade. So while it validates the situation in under perfect laboratory conditions, it does not reflect the true extraction conditions that happen every day for medical and recreational extractions.

The important points of this patent are the temperatures. The desired solvent exists as a gas at room temperature, but can be in the liquid phase when put under pressure and temperature constraints. Controlled temperatures not only dictate the phase of the hydrocarbons (i.e. gas or liquid), but also prevent degradation of cannabinoids, preserve terpenes, and reduce solubility of plant lipids.

Some side notes on the choice of solvents were low toxicity, low environmental impact, and generally recognized as safe for use in pharmaceutical applications. These factors combined are some of the reason for using propane and butane as the industry standard for cannabis extractions.

That covers the theory behind the process. Below you’ll find a few points on the methods that make this a very good process.

Assuming one has an understanding of the standard closed loop extraction process, you can imagine how this process goes. You’ve passed your butane/propane through the extraction column and the extract is sitting in the collection vessel.

It does not specifically say in the patent, but there are two ways this could go. The first option is that the butane is boiled off (reclaimed) to a certain percentage, and then transferred to a secondary container. The second is that the butane is allowed to boil off without care for reclaiming. I find the second option less likely, but it is a possibility.

Assuming the first option, the partially purged extract is transferred to a second collection chamber while it is still of high enough viscosity. This process is called a cannula transfer. The second collection vessel is where there are inert conditions, and the butane/propane is evaporated off.

Solvent is evaporated by increasing the temperature of the second collection vessel and passing inert gas over the surface of the extract – in this case, I’m almost sure the author used a side-arm round bottom flask. I’ve covered the value of inert gasses in a few of my posts at Hemphacker, but it is definitely a standard operating procedure in a chemistry laboratory. In this case, they use argon gas to assist the removal of butane from the extract.

Using inert gas helps remove the solvent by changing the dynamics of partial pressures at the surface of the solution – this is a long topic and out of the scope of this article. However, the change in partial pressure increases the rate of evaporation for butane and allows one to to reduce the temperature to 4C, from what would normally be done at much higher purging temperatures. Now we’re in terpene preservation territory.

The low temperatures are beneficial because it reduces the degradation of the cannabinoids, and also keeps the terpenes in a low-volatility condition. In addition, the author claims that these temperatures make it easier to handle the extract.

As a result of evaporating off propane/butane at a lower temperature, the author claims that the invention induces a more crystalline form of the extract rather than the formation of a homogenous solid. I would hypothesize that the slow cool temperatures allow crystal formation, in what is a more gentle process that does not disrupt the nucleation of seed crystals. They claim to have shown this by x-ray diffraction, but no data is given to supplement the claim. Still, the extract is not 100% crystalline, as claimed by the author; as an analogy, think of how some parts of an extract will auto-butter before others.

One point to keep in mind is that this is a pure starting material, for the sake of explaining the invention of the process. By experience, a chemist performing extractions knows that the results vary by strain to strain, because of the different distribution of cannabinoids and terpenes.

This is a fundamental patent to understand the origins of live resin extractions. This author has several more patents on the subject, but I chose to write about this one because it was the “first mover.” The cannabis community owes much thanks to pioneers in science, who laid the way for us to preserve the ultimate essence of the plant.
I hope that you all find this interesting. Please share your thoughts and comments!

Hemp Hacker Glossary

Here are a few terms that will help you understand both the extraction process and components of an extractor. Please post your questions or any other terms you’d like to have defined – your feedback is always appreciated.

Process Terms:

Concentration – the amount of something (in weight) in a given space (volume) – e.g. pounds/gallon, grams/milliliter.

Contamination – any impurity in product – e.g. plant lipid/waxes, plant cell wall debris, water in extracts.

Continuous Shower – a top down shower of butane over a column packed with plant material. The butane is recycled from the extractor collection chamber in the gas phase. It is pumped through the recovery pump (RP) and passes through the condensing coil (CC). The butane changes from the gas phase to liquid phase, and passes through the recovery manifold (RM), and back through the top of the column. The plant material is then “continuously” showered with cold liquid butane. This strips the plant material of all its butane soluble molecules – i.e. cannabinoids, terpenes, and plant lipids/waxes

Cooling Bath – a mixture of ice and water or dry ice and ethanol that is used to cool down extractor components like the recovery cylinder (RC)

Fractions – different grades of trichomes/hash depending on amount of plant material contamination.

Gas Phase – butane is a gas

“Hg or inches Hg – signifies the vacuum pressure of the system in “inches” of mercury.Maximum vacuum is 29”Hg while zero vacuum is 0”Hg. It’s a way of describing negative pressure, just like MPa (metric system measurement – mega Pascals), KPSI (standard/US system measurement – thousands of Pounds Per Square Inch), or bar/atm (metric measurement – the pressure in terms of the number of atmospheres)

Liquid Phase – butane is a liquid

Risk based approach – examining the inherent risks involved in a process and eliminating risks to improve the product safety or process safety.

Vacuum – the vacuuming step is the first step in preparing the system for extraction. It is necessary to vacuum the extractor for two reasons. First it creates negative pressure that pulls the butane into the extractor. Second, it removes the majority of the atmospheric oxygen in order to prevent conditions where butane can ignite – remember that butane needs oxygen in order to combust.

Winterization – the process that removes plant lipids/waxes from an extract.

Component Terms:

Condensing/cooling Coil (CC) – a stainless steel coiled tube that acts as a heat exchanger. As butane gas passes into it, it cools down the gas and it changes over to the liquid phase – this is called a phase change of matter.

Dewaxing Column – a column that has cooling capabilities with dry ice and ethanol. It typically requires a 1 hour soak time to achieve dewaxing, although the process is often incomplete if not done under the proper conditions.

Gaskets – Buna, Viton, or PTFE “rings” that are placed between two sanitary fittings

High Pressure Side Recovery Manifold – the red side gauge and valve that opens and closes to allow gaseous butane to flow in to the manifold. The gas can be condensed into the liquid phase by maintaining a pressure of 100PSI and can be diverted back out the low pressure side or back into the recovery cylinder.

Low Pressure Side Recovery Manifold – the blue side gauge and valve, that opens and closes to allow liquid butane to flow into the extraction column.

Recovery Cylinder Liquid Side Valve – the valve (either blue or red) that has “LIQUID” printed on it. This valve opens up the extraction system to liquid butane. Different manufacturers have different conventions, so don’t assume you have the liquid side just because it’s blue.

Recovery Cylinder Liquid Straw – the tube that is attached to the recovery cylinder liquid side needle valve. The straw allows liquid butane to flow into through the valve into the extraction system.

Sanitary Fittings – individual pieces that make up the stainless steel columns and spools. Pieced together, they make the extraction column and extractor collection chamber. Sanitary fittings are held together by high-pressure triclamps


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

“Simplicity, simplicity, simplicity” said Henry David Thoreau…

In any process, it’s best to simplify it if you can. In any math class, you want to simplify your algebra before doing more complex math. This is a matter of time, efficiency, and of course money. What I’m proposing here is that people simplify and perhaps improve their extraction process.

No doubt, hydrocarbon extractions are a risky business. On the small scale, you anywhere up to 12 pounds of butane in-line to your extractor at any given time. That has a significant explosion potential – the endless news stories of people blowing up houses describe it well enough.

Since most extractors have dry ice on hand to freeze their plant material or to control temperatures of their butane, you can just as well use some of that dry ice to concentrate your trichomes. This may seem like more work on the front end, but it does save you work in the long run, and is also much safer since it means less time cycling butane through your extractor.

It’s a matter of concentration (i.e. density).

In my former life as a protein chemist, concentration was everything. Concentration is described by the number of Moles of any substance, divided by the the volume (or the amount of liquid) the substance is dissolved in. Concentration is a close cousin to density. For the sake of our discussion, we’ll talk in terms of density.

Density can be described as the amount of weight divided by the amount of space it takes up (i.e. volume) – e.g. pounds/gallon or kilograms/liter. Now imagine that you have 1 pound of buds, and that takes up a space of a 3”x36” column. A 3”x36” column has a volume approximately 0.7 gallons. This works out to be 1.4 pounds per gallon or 0.17 kilograms per liter.


Now take that same volume of buds and make dry ice hash with it. Your yields will vary depending on the strain, but you can expect anywhere from 15-25% yields. This will produce a much smaller volume of concentrated trichomes. You don’t have to do much math to understand that weight for weight, a column packed with trichomes has more cannabinoids and terpenes compared to a column packed with nugs or trim.

To further the point, the density of cannabinoids and terpenes is much higher in a pile of trichomes than is in a equally sized pile of nugs. The point is that by concentrating – ie increasing the cannabinoid and terpene content while decreasing the volume – you increase the efficiency of your extraction.

Your goal is to get the highest yield dry ice extraction as possible.

In this case, you don’t need to make perfect, connoisseur grade, bubble hash. The amount of plant matter picked up is insignificant to the process since it will be filtered out during extraction.

So you’ve just taken 1 pound of dried buds that takes up 0.7 gallons of space and turned it into what looks like a powder that weighs 0.15-0.25 pounds and takes up something like 0.1 gallons of space. This defines the verb “to concentrate” as known by a chemist – you’ve just simplified your algebra. Now you have a product that will likely fit into a 3”x6” column, and can be run through the extractor.

The great part about this method is that you can filter out the plant material with your filter plates. You end up with a fine oil that is rich in terpenes and cannabinoids while limiting the amount of waxes and other phytochemicals that would be extracted from plant material. This is a major increase in efficiency.

Materials and preparations for making dry ice hash.

Dry ice hash is relatively easy to make. The tools of the trade are a 220 micron bubble bag, dry ice, and a flat surface to shake it out onto. A simple way of doing this is setting up a 2 bucket system, where one bucket fits into another. The top bucket will have its bottom cut out, and the 220 micron bag slips over it. The second bucket, with it’s bottom intact, fits over the 220 micron bag that’s wrapped over the cut out bucket, and is where you collect the trichomes. Pull the bag tight over the cutout and tie off the string on the bag to keep it tight against the bucket.

Dry ice costs $1.25/pound from the local grocery store, so the material cost is relatively inexpensive. You can be generous with the dry ice. A 1:1 ratio of dry ice to buds is the higher end, and you can get by with less, but you may sacrifice yields. Freeze your buds for 48 hours in the freezer before hand. Alternatively, you can just as well let the dry ice freeze them.

Making dry ice hash.

Break up your dry ice into 1” chunks to increase the surface area coming into contact with the plant material. Place the 220 micron bag over the cut out bucket and then put your buds into the 220 micron bag along with the dry ice. Gently stir the buds around with the dry ice, place the lid on the bucket, and allow the mixture to sit for 10 minutes to freeze the the temperature of the dry ice. At most, full freshly cut buds resting in dry ice take 30 minutes to freeze.

After freezing, vigorously shake the bucket. Alternate between shaking it up and down and swirling it around. Periodically check the bottom of the second bucket to see the quality of the trichomes.

Extraction and fraction quality.

Are the trichomes at the bottom of your bucket a light amber/golden color? Or are the trichomes now mixed with pulverized plant material?

You will likely want to collect a few different fractions – head fractions to heart fractions to tail fractions, just like a moonshiner. Shake a few times and look in the bucket. You might want to keep the first fraction for full melt hash (head fractions). Then shake vigorously and take a few more fractions (heart fractions). Finally collect the last fraction that will have the most broken up plant material in it (tail fractions). Now you have a range of grades (i.e. piles of different quality), ranging from golden trichomes to trichomes mixed in with plant material that have a green tint – heads through hearts through tails.

You can repeat this process several times over to collect all your grades as different fractions, but from multiple batches of fresh materials. Then you can pool them together and use them for individual batches in your extractor. Normally you pack your column with buds. Dry ice hash, or trichomes, just get poured into a smaller column and run as normal.

The goal here is to improve efficiency.

Less time running butane solvent through your closed loop extractor is a very good thing. It takes attention to detail every moment it’s running. One slip up, and you may lose your product or your life. From a risk based approach, Hemp Hacker believes this to be the very “best practice” that one can immediately implement in their extraction process.

The butane extraction side of the process works just like a normal nug run, but with an additional concentration step. While it adds a step on the front end, it reduces multiple steps on the back end. The main difference is that you concentrate the trichomes with dry ice in the first place, then dissolve them with butane. On a nug run, you would just be dissolving trichomes from buds with butane, and then collecting the cannabinoids and terpenes as an oil; the caveat is that you will have to do many more nug runs than with a trichome run.

Benefits of a 2 step extraction process.

While you may have green (tail) fractions that aren’t suitable for connoisseur grade hash, the plant material contamination will be filtered out by the filter plates at the bottom of your extraction column. This process takes care of the number 1 problem hash connoisseurs complain of – lack of potency due to plant material contamination in dry ice hash. You get the best of both worlds. An opportunity to collect the highest grade dry ice hash fractions with little to no contamination, and you also get to perform an extraction on the fractions that are contaminated with plant material and filter it out, yielding a high quality reduced wax extract.

Controlling humidity and water content during extractions is an important component to making quality extracts. When water contaminates an extract, it increases its tendency to auto butter when making shatter. This translates to reduced stability of an extract and a shorter shelf life. The two step process eliminates the largest source of water – the plant materials. The dry ice freezes all the water in the plant material, be it fresh frozen or crispy dry nugs, and allows the frozen glandular stalks that support the trichomes to be sheared off. The sheared trichomes fall off though the 220 micron bag and you have majorly reduced a source of water contamination (i.e. the plant materials).


Using the two step process of dry ice hash extraction followed by butane extraction in a closed loop system is a drastic improvement of efficiency. It reduces the total number of runs required, the amount of butane that needs to be dehydrated, and the inherent risk of using butane and hydrocarbons as a solvent. Given those factors, turning your one step nug run extraction process into a two step nug to trichome process will greatly improve your efficiency and in turn, profits.


Concentration – the amount of something (in weight) in a given space (volume) – e.g. pounds/gallon, grams/milliliter.

Contamination – any impurity in product – e.g. plant cell wall debris, water in extracts.

Fractions – different grades of trichomes/hash depending on amount of plant material contamination.

Risk based approach – examining the inherent risks involved in a process and eliminating risks to improve the product safety or process safety.


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

There are probably a dozen different ways to pack a column. While as a Sergeant in the Marines, I was sometimes amazed by the different interpretations my Marines would take on what I thought to be a clear set of instructions… So it goes. Everyone has their own interpretation on how to do things.

The process of packing a column is no different – everyone can have their own interpretation. In my view, there are two “best practices” in order to pack a column. I’ll explain the two and you can choose what works best for you.

Either way, your goal is to reduce the amount of condensation on the buds and the inside of the column. Condensation is the enemy because it reduces the ability of butane to solvate the lipid/waxy bilayer of the trichome – in botany, that layer is called the cuticle. If the cuticle is surrounded by frozen water, the butane can’t penetrate and the extraction efficiency decreases along with your yields.

Temperature and time.

You’ll likely have two options for freezing your buds and column. I will assume that everyone who is doing extractions has, at a minimum, a freezer capable of maintaining 0C temperatures. In this case, you will need 36-48 hours to ensure that all water has been locked up in its solid phase as ice.

If you have dry ice on hand, which most live resin extractors do, you can pack your freezer with a bed of dry ice. When you freeze your buds and/or bud packed column on dry ice, you drastically speed up the freezing process. A thin layer of freshly picked buds packed into a vacuum sealing bag will be frozen in 30 minutes. If you’ve pack it into a column, give it 2 hours to ensure a full freeze.

Method 1: pack freshly cut buds into the column and freeze.

This is probably the easiest method. Simply cut the room temperature buds up into 1/2”-1” diameter. The column should also be at room temperature. Loosely pack the column with the buds. You’re now ready to freeze the column and buds. Once fully frozen, you can begin your extraction process by vacuuming out the extractor and column.

You should vacuum out your column only after you have frozen the buds. The reasoning is that vacuuming unfrozen buds will cause the plant cell walls to rupture, releasing the water and phytochemicals that you are trying to avoid extracting in the first place.

Method 2: freeze freshly cut buds and column separately, then pack the column.

This method is just as sound as the first. Again, this is a matter of preference, but has its own merits. Cut your buds down to 1/2”-1”. Pack them into a vacuum sealed bag and evacuate the bag – as in method 1, pulling full vacuum may rupture plant cell walls. In this case, a vacuum sealer will not develop the same pressure as the vacuum pump used to evacuate your extractor. That said, the biggest benefit of this method is being able to freeze larger quantities and store them in the freezer until you’re ready to extract them.

In the meantime, you will freeze your empty column until its temperature is the same as the frozen buds. In this situation, you want to pack your column quickly to prevent condensation to form on both the buds and the interior of the column wall. Ideally, you will have a room that has a very low relative humidity. Once packed, you’re on your way to assembling the column to the extractor and start to pull a vacuum.


If you have the tools of the trade on hand – ie a vacuum sealer and dry ice – I prefer method 2. If not, you will not be at a total loss to use method 1 and just freeze the plant matter in the column. If you have several columns on hand, you’re not at much of a loss. If you have one column on hand and no vacuum sealer, you can still get by with a modified version of method 2.


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

Setting up your recovery pump is a simple process on most extractors. You will likely have a 3/8” recovery hose connected to the lid of your collection chamber, where the gaseous butane is pulled through to the recovery pump (low pressure side) and pumps out to the high pressure side to be dumped into the recovery cylinder. 

A real world example by an awesome company.

There is a very good example of this setup on the market by Precision Extractors. If you pull up their website and take a look at the back of the extractor, you’ll see there is a column that is plumbed and placed behind the secondary recovery cylinder (on the right). That column is filled with 3A molecular sieves and is plumbed to the primary filling cylinder (on the left).

Their system works by pumping butane from the primary filling cylinder into the primary extraction column. After passing through the primary extraction column, it passes into the dewaxing column. The butane is evaporated off by heating the collection chamber and the negative pressure from the pump, pumping the butane into the recovery chamber.

From there, the butane passes through the pump in the gas phase to the 3A molecular sieve column. The butane gas passes out of the 3A molecular sieve column and is pumped into the primary filling cylinder where it condenses into the liquid phase due to the cold temperatures and higher pressure.

Although Precision Extractors have this set up natively on the PX1, there’s no reason a similar system can’t work with your current extractor. The explanation follows below.

Setting up your current extractor for in-line dehydration.

This is a simple system. It really just requires an additional column with end plates, an inline filter, and one additional stainless steel braided hose. Read up on the post about dehydrating your butane. On average, 1000g or 1Kg or 3A molecular sieves will be have enough capacity to dry all the butane you could use in a week. Use an appropriately sized column and pack it with the sieves. Connect a filter plate and a filter at the bottom of the column, and you’re nearly there.

Connect your 3A molecular sieve column (8) between the collection chamber (10) and the low pressure side of the recovery pump (7). While you may say that in-line filter driers can do the job, they’re not really up to the task when you do the desiccant math. This is a step that is better done with more desiccant than less. This is a simple improvement on what most people already do. You can certainly use an inline filter drier, but this ensures an efficacious dehydration.

Dehydration is an ongoing process.

While putting a column of molecular sieves inline is an improvement, it is only part of the process. It is very important that the molecular sieves are dried out after a day’s extractions. The nice part of this setup is that you can easily remove the molecular sieves from the column. That’s important because you need to dehydrate your sieves after you use them so  they’re ready to dehydrate your butane – the beauty of molecular sieves is that they are re-useable.

Once you’ve removed your sieves, pour them out into a pyrex dish. You can then put them into your vacuum chamber, apply heat and vacuum, and have fully recharged/dehydrated desiccant ready for use in the morning. This is a standard process in the pharmaceutical industry where drug substances must be kept free of humidity while in storage, and the molecular sieves are periodically recharged.


For the price, you can’t miss the beat on dehydrating your butane. Not only does the dehydration improve your yields, it also helps save the seals of your pump that do not react well with water. Given those two improvements, the small investment of molecular sieves in-line from your extraction chamber to the low pressure side of your pump will pay itself back quickly.


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

Water kills butane hash oil yields

Butane picks up water during extractions and causes lower yields.

Butane picks up 3.25mL of water per liter and propane picks up 3.9mL of water per liter. To put it simply, water in butane and propane takes up space that prevents cannabinoids and terpenes from being fully extracted. That’s a problem.

How does water contaminate extractions?

Water contaminates extractions because of its effects on solubility – water in your butane and propane decreases the potential solubility of cannabinoids and terpenes, but it also picks up water soluble contaminants like plant chlorophyll, alkaloids, and flavonoids. If you’re looking for the simplest solution, just dehydrate your butane/propane. If you’re looking for perfection, purge your extractor with CO2.

Improve yields in 2 simple steps.

It’s all about the chemistry of inert conditions/reactions. There are two simple steps for high quality live resin extractions: 1. dehydrate your solvents; 2. purge your live plant materials and extractor with a dry gas like CO2. Putting together the steps of dehydrating your butane and purging your extractor will most certainly increase your yields, but it also functions to reduce contamination.

Dehydrating butane and propane is the most important step to improve yields in live resin and regular extractions.

Dehydrating your solvents is as easy as packing your extraction column with a substance such as 3A molecular sieves or activated alumina. Molecular sieves and activated alumina are used to dehydrate butane/propane in the gas phase – ie you do not pass liquid butane/propane through a column packed with these desiccants.

3A Molecular sieves are widely employed in the lab setting, where they’re used to dry solvents or keep solvents dried in the first place – they can hold up to 19-20% of their water weight. Molecular sieves are also FDA Approved for direct contact with consumable products. Activated alumina has a higher water capacity. It’s used in number of industrial drying applications for hydrocarbons, but there isn’t sufficient data proving its safety beyond “Satisfactory” compatibility with butane and propane.

Check out the post about recovery pump setup and see how to set up a system that will effectively dehydrate your butane and propane.

Desiccant math made easy.

You need to do little math to figure out how much space your molecular sieves will take up, and to figure out how many grams of molecular sieves you need. Molecular sieves cost approximately $100/500g, but they are nearly infinitely reusable. You can regenerate or dehydrate them by heating them up in a vacuum oven and pulling full vacuum. Here’s the math:

lbpergaltokgperliter (1)

Most extraction artists use US pounds to measure their butane, so we have to do a few conversions. Let’s say you have 12 pounds of butane. You need to convert it to kilograms, so you can take into account the density of butane (assume 1bar/14.5psi and 20C/67F); you use the density to convert the mass (i.e. weight) of the butane into a volume (liters). Now you can multiply the number of liters by the water:butane conversion factor to determine the amount of water that the 12 pounds of butane can hold. Finally, multiply the amount of water in your butane by the water capacity of the molecular sieves. This shows you minimum number of milliliters or grams of molecular sieves you need to dehydrate your butane. That said, 675mL of molecular sieves weighs approximately 1000g. Buy two 500g containers and you’re home free.


Dehydrating your butane is a step forward in improving your extractions. Not only does water in butane decrease extraction efficiency, but it also causes increases the extraction of plant contaminants like chlorophyll, alkaloids, and flavonoids. If you’re looking for perfection, you’re going to run your extractor like an organic chemist synthesizing a compound under inert conditions. You’re drying off all the water from the extractor walls with a hot air gun, then you’re pumping out the water trapped in the atmosphere by pulling a full vacuum. These steps make for a higher quality and more consistent product.


Thermodynamic properties of butane and propane:



Activated alumina:



Molecular sieves:



As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

This is how a chemist makes live resin, attending to every detail. Sometimes the additional work is well worth the reward. Every person running an extractor is a scientist in one way or another. Over time, you test things, figure out what works, and you have the best possible product. If you are looking to maximize the quality of your extracts, consider these points.

Inert conditions are important for humidity control.

The amount of humidity in the air is dependent on where you live – Denver is generally dry, whereas Seattle is generally humid. If you’re in Seattle or any other humidity prone area, inert conditions are important to factor into making a high quality product. That starts with running a dehumidifier at full blast in the room that you’re preparing your fresh plant materials in.

Drying your inert gas.

Argon is the ultimate and preferred inert gas. Alternatively, everyone has access to CO2, and drying off CO2 is an easy process with anhydrous calcium chloride. Pack a small column with filters at either end and pass your CO2 gas through the column. This can be used directly in-line from your CO2 cylinder into your extractor as well as to purge the bags you’re freezing your plant material in.

Inert conditions in an extractor.

One of the first steps of performing a closed loop extraction is to vacuum out the extractor. There are a few reasons to do this. One reason is to remove as much air as possible in order to prevent a potential explosion from oxygen mixing with butane. The second reason is to create a vacuum in the closed loop system that will pull liquid butane into the extractor from the recovery tank. While pulling a vacuum on an extractor removes most of the air, water can still be left behind in a very thin layer – i.e. a monolayer.

Purging your extractor with inert gas or dried CO2 helps remove the water monolayer of condensation.

The purpose of purging your extractor is the same as the purging your bag filled with fresh plant material (see below) – you’re removing the ambient humidity that would otherwise condense on the walls of your extractor and contaminate your extract. Dried CO2 gas can be run through the extractor to help eliminate water.

Vacuum out your entire extraction system. Once vacuumed, fill the extractor with dried CO2 from an inlet port. Allow the extractor to completely fill up with the CO2. Allow a portion of the CO2 to escape the extractor, releasing more ambient humidity, then vacuum the extractor back down to it’s maximum vacuum. There are several ways to go about this process, and it really depends on the design of your extractor.

You can repeat this process, but in reality the first CO2 purge followed by pulling a vacuum on the extractor will take care of the remaining water that was in the atmosphere of the extractor.

Minimum standards for inert conditions and removing the water monolayer of condensation from your extractor.

I get it – purging with CO2 sounds like it adds a lot of work. The minimum standard to achieve inert conditions is quite simple: heat and dry off the interior of your extractor with a hot air gun (aka blow dryer). This dries off the monolayer of water that will have condensed onto the interior surface of the extractor. Once you’ve dried off all interior surfaces of the extractor, seal off the extractor, and purge to full vacuum. Close off all open ports to the extractor and allow it to cool down. Connect your column and begin your normal extraction procedure.

If you’re going the extra mile, complete the minimum standards described above, then fill the extractor with CO2, and pull another vacuum.

Purging live plant materials with dried CO2 prevents water condensation during freezing.

Purging live plant materials prior to freezing is mentioned in the temperature post here on Hemp Hacker, but it’s also touched on here. The reason for purging your fresh plant materials before freezing is that there is humidity in the air/atmosphere. That atmospheric humidity has a tendency to condense on the buds as they are freezing. Purging your freezer bags prior to freezing reduces this tendency.

Dried CO2 gas is ideal to purge with because it displaces the ambient air/humidity from the bag that’s used to freeze the plant materials. The trick is to make sure all humidity is out of the bag – about 3X the bag volume is a good amount, and you can be relatively sure that all the ambient humidity is purged out. Once purged, the bag can be vacuum sealed and frozen in a freezer, or even better and faster by submerging the bag in a dry ice/ethanol bath.


If you’re in to making the highest quality products, purge both your plant materials and your extractor with dried CO2 gas. These two steps reduce the amount of water in your starting materials and will reduce the tendency of auto buttering extract. In addition, it will improve the stability of your extract.


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

Four temperatures parameters.

Terpenes are a valuable product captured the extraction process. Not controlling temperatures through the extraction will cause you to lose terpenes. There are four temperature parameters that need to be controlled in live resin extractions – fresh plant materials, butane, column, and purging temperatures.

Freezing live plant materials under inert conditions.

Live resin requires low temperatures to extract cannabinoids and terpenes and leave behind water and plant waxes. Since dry ice and ethanol are required for almost every step, it makes sense to use it for flash freezing the plant material. This is done by filling vacuum bags with fresh plant material in a way that maximizes surface area. Once filled with plant material, the bags are filled with dried CO2 gas to purge out the humidity from the room. The bags are vacuum sealed, dipped into a dry ice bath until fully frozen, and are then made ready to fill into a prechilled column.

There are many ways to freeze plant material. Choose the one that works best for you. 

Cooling your butane with a condensing coil.

Control your butane temperature before it comes in contact with the plant material. If you don’t, your freshly frozen plant materials will thaw from the warm butane, and start to release plant lipids. Pass your butane through a condensing coil that is submerged in a dry ice/ethanol bath – on average, the dry ice bath will cool the butane down anywhere from -20C to -50C. The cooling capacity, or rate of cooling, is dependent on the size of the bath and the amount of dry ice added to it. Once cooled down, the liquid butane passes into your packed column and the extraction begins.

Temperature control at the column is key to long soak times.

A commonly missed point is that the column must be frozen in the freezer prior to extraction. Do this, and you’re one step ahead of the game.

A problem with long soak times is that the frozen plant material can be warmed up if the column temperature is not controlled. This causes the water that’s locked up in the solid phase (i.e. ice) from plant cells to release water, water-soluble phytochemicals, and plant lipids/waxes. 

After the cooling coil, butane temperature needs to be controlled at the column. Keeping the column at a temperature less than -20C (optimally -30C to -40C) ensures water and waxes do not contaminate the extract. The column temperature can be controlled by a dry ice/ethanol bath; it can be connected to a cryogenic pump or just be an open sleeve/cylinder filled dry ice and ethanol. If dry ice isn’t available, an ice bath will improve your extractions.

Transferring to thin film and purging.

You’ve finally got your live resin extract in the collection chamber of your extractor. Live resin extracts are low viscosity – the additional terpenes decrease the internal friction of the liquid. Pour the extract onto silicon mats, then scrape out the collection chamber with a silicon spatula and transfer it onto a second mat. You’re now ready to purge.

Live resin purging – temperature and time.

Two important components in any chemical reaction are temperature and time. Higher temperatures cause loss of terpenes, but decrease the purging times to boil off all the butane. Keep your purging conditions below room temperature and not much below 5C. This preserves terpenes, but is still above the boiling point of butane. To make up for the lower temperature, increase the amount of time spent purging to 5 days. This is the simplest process to preserve your terpenes, and make your live resin runs worth while.

General purging tips.

A favored way of purging is to heat the extract up to it’s purging temperature for 30 minutes without pulling a vacuum. Once the oil is up to your desired purging temperature, you can pull a full vacuum. Purging times vary from strain to strain, but you can follow the bubbles to see when your extract is purged. The purging has nearly completed when the major bubbles of butane stop forming – those bubbles are typically large and burst when they reach their maximum size. You’re looking for the point when the bubbling slows down and only small bubbles form. At this point, you can dial in your process with residual solvent testing at your local laboratory to confirm when your extract is fully purged.


Properly controlling temperatures of fresh plant materials, butane, column, and purging will improve your process. There are multiple benefits at each step, that when combined create perfect conditions for preserving the essence of the fresh plant – the terpenes. Not all starting materials are worthy of making live resin. When you do have good starting materials, you will be rewarded with knockout flavor and taste that would have otherwise been lost to the atmosphere. Follow these steps and enjoy the experience.


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.

Minimum standards for making live resin hash oil extracts

So what is a bare bones method to making live resin? Well, just about any extractor can be made to meet the minimum standards of a terpene rich extract. Whether you’re trying to go with fresh frozen material, or material that is just about ready to start curing, you can do your best to preserve terpenes and minimize the amount of plant waxes that are extracted. I’ll keep this post short, since most of this information is covered in other posts.

Step 1: dehydrate your butane.

This is a simple step that few extraction artists I’ve spoken to take advantage of. If there’s one thing that helps the extraction process, it’s this. If you don’t dehydrate your butane, you increase the chances of there being blockages in the column or even your braided stainless steel hoses caused by freezing water. In addition, it improves the extraction efficiency because water will change up the solubility properties of the butane.

Hands down, putting 3A molecular sieves in-line on the low pressure side of your recovery pump will improve your extraction efficiency. It’s not hard to do, and it will improve your process and end product.

Step 2: freeze your plant materials.

Whether you’ve chosen to run fresh frozen, dry your buds to the point before curing, or cure your buds, you’re going to benefit from freezing them before extracting. This equilibrates the temperature of the buds to the temperature of the butane, and reduces the amount of plant waxes pulled during an extraction. In step 3, you’re going to freeze your butane. Now imagine this mass of buds packed into your column, and both the buds and the column are at room temperature. Now imagine that -50C butane rifling into the column and hitting buds and stainless steel that are at a warm 20C…

You can surely see where this is going – the butane will be warmed up and the buds will be cooled down. When that happens, you’re defeating the purpose of chilling your butane in the first place – you’re now extracting the very plant waxes that you were trying to avoid extracting in the first place! The point is, try to make everything as cold as possible to get the best results. Terpene rich extracts are higher quality and have more medicinal potential – don’t skimp out on this simple step that anyone can accomplish.

Step 3: freeze your butane.

This is perhaps the simplest step to take to improve your extractions. If you’re going to take any steps towards making live resin, freeze your plant materials, column, and butane. You don’t necessarily have to dehydrate your butane, but if you take steps 2 and 3 into account, you’ll certainly improve your product.

While you may not have dry ice on hand, you do likely have ice on hand just for the sake of recovering your butane. Take the time to submerge your recovery cylinder in an ice bath. That ice bath can be dry ice with denatured alcohol, or it can just be ice, salt, and water. Either way, this step will reduce the amount of waxes that are butane soluble by reducing temperature.

Step 4: cold purge.

While you may not have the capacity to purge your extract with an inert gas (e.g. dried CO2 gas), you do have the ability to extract at room temperature and pull a full vacuum, assuming you have a vacuum chamber. The boiling point of butane is -0.5C at standard atmospheric pressure (1 bar/1 atm/14.5 PSI). When you pull a vacuum, you reduce the boiling point, and a major factor becomes time. Give an extract enough time at room temperature while under vacuum, and you’ll be able to pull off all the butane while preserving terpenes.

While it’ll be different for every situation (elevation, room temperature, quality of vacuum), 5 days at room temperature with a full vacuum will purge out your butane and leave you with a terpene rich extract. For smokable forms, I always suggest having a residual solvents test run by your local testing facility to make sure that you’re below the threshold for butane.


These four steps will take you well on your way to higher quality extracts that preserve terpenes. If you can start working in this direction you’ll be using the trade secrets that some of the best extraction artists use day in and day out. Best of luck and enjoy those terpenes!


As always, if you have any questions please post them in the comments section. Your questions and time are valuable and we will make every attempt to help you through your process.