Can You Use Rubbing Alcohol to Extract THC From Weed?
Extracting compounds such as THC and CBD from marijuana enables users to benefit from a high concentration of a specific cannabinoid. For example, proper THC extraction allows you to create cannabis concentrates, which could have a THC level of over 90%! Extraction via alcohol is one of the most common methods.
When it is performed correctly, it is a safe form of extraction, BUT you must choose the right type of alcohol. Do NOT select denatured alcohol because it contains harmful ingredients which make it unfit for human consumption.
What is Rubbing Alcohol?
There are several types of alcohol, and not all of them are suitable for drinking! The alcohol we drink in the form of beer, wine, or spirits, is ethyl alcohol produced by yeast. In winemaking, for example, the yeast consumes the sugar in grape juice and creates alcohol.
Ethanol is the same kind of alcohol found in whiskey and is also used as car fuel. It is different from the stuff you drink because it has been distilled to the point where it is almost entirely alcohol. The denatured alcohol you find at the drug store is also ethanol, but it is poisoned to prevent people from drinking it. Food grade ethanol is a popular solvent for THC and CBD extraction and is still used by several big sellers.
Rubbing alcohol is the term used to describe either ethanol-based liquids or isopropyl alcohol. While denatured alcohol is classified as a methylated spirit, rubbing alcohol is a surgical spirit. It is widely used in medicine as a topical application. It is often a form of denatured alcohol made from a unique solution of 70% ethanol or isopropyl alcohol in concentrated form.
The term ‘rubbing alcohol’ is actually a generic term to describe ethyl or isopropyl-based products with similar qualities. In the UK, rubbing alcohol is often referred to as ‘surgical spirit.’ In North America, methyl salicylate is added to rubbing alcohol, which is commonly known as wintergreen oil. In Canada and the United States, manufacturers are allowed to use their own standards of formulation, as long as the isopropyl or ethanol alcohol content is labeled and ranges from 70% to 99%.
Both ethanol (chemical formula C2H5OH [also written as C2H5OH]) and isopropyl alcohol (chemical formula C3H8O) are used as disinfectants. However, while ethanol has no lasting short-term effects when consumed, isopropyl alcohol gets converted into acetone in the liver; which means it is incredibly toxic.
The term ‘rubbing alcohol’ was first used during the prohibition era in the 1920s. It was used as an ointment in massages and was rubbed into the skin. As it was an age where the consumption of alcoholic beverages was illegal, it was necessary to distinguish the type of alcohol one drank from the kind used in medicine.
Is it Safe to Use Rubbing Alcohol for THC Extraction?
There is some confusion over whether rubbing alcohol is even safe for use as a solvent for THC extraction. While it is true that isopropyl rubbing alcohol and denatured alcohol share similarities, their chemical structures, toxicity, and means of production are different.
Neither version is suitable for human consumption. Indeed, only food grade ethanol or ethyl alcohol can be safely consumed. Isopropyl alcohol is the name of a substance, whereas denatured alcohol is a commercial product which can contain several materials including ethanol and isopropyl alcohol. It also includes denaturants which make it unsafe for consumption.
However, there are different types of rubbing alcohol. In the United States, in accordance with ATF rules, all preparations classified as rubbing alcohol must have toxic additives to limit human consumption and prevent alcohol abuse. These forms of rubbing alcohol must have between 87.5% and 91% of absolute ethyl alcohol. The rest of the solution contains denaturants, water, and perfume oils.
There are also specific isopropyl rubbing alcohols with anywhere between 50% and 99% isopropyl alcohol. Therefore, if you are going to use rubbing alcohol for THC extraction, you will ideally choose one with up to 99% isopropyl alcohol.
Although you CAN use isopropyl based rubbing alcohol to extract THC or other cannabinoids from marijuana, it is safer to use ethanol. If you plan to use isopropyl alcohol for whatever reason, the process is known as Quick Wash Isopropyl (QWISO).
How to Perform QWISO THC Extraction
Isopropyl extraction involves stripping the trichomes from marijuana flowers to create potent hash oil. If you want to use this method of extraction, you’ll need the following equipment:
- A metal screen or filter (you can use a permanent coffee filter)
- A clean glass bowl
- Paper coffee filters
- A glass pot (a coffee pot works well)
- A glass mason jar
- A plastic storage container
- A large sieve; we recommend a large and a small sieve if you are using more than 10 grams of bud
- Cutting utensils
- A fan
- An oven
- 100-200ml of isopropyl alcohol
- At least 10 grams of bud
- A razor blade to gather the extract
Preparing for the Extraction Process
When it comes to THC extraction using isopropyl alcohol, preparation is crucial and begins several hours before you attempt the process. Make sure every container you plan on using is extremely clean and dry. Next, grind up your buds into a small jar and put it, and the alcohol, in a freezer for a few hours (you can even do this overnight) to ensure they are as cold as possible. Isopropyl alcohol’s freezing point is approximately -128.2 degrees Fahrenheit, so there is nothing to worry about!
You need to freeze the bud because its trichomes fall off far more efficiently at very low temperatures. You can attempt the extraction process without freezing, but it will result in a far smaller amount of THC.
Final preparation steps include placing a coffee filter into your jar to create a type of bag. If you plan on extracting THC from a large amount of bud, cover the entire surface area of your large sieve with filters and place the smaller strainer on top.
Extracting THC Using Isopropyl Alcohol
Pour all of the alcohol into the jar containing the weed. Make sure the ground buds are entirely submerged in the alcohol. Close the lid and tighten it securely. Shake the jar vigorously for 30 seconds. Don’t shake the jar for too long because you could extract too much chlorophyll, which will leave a bitter taste.
Next, pour everything through a sieve and filter the contents in a jar. The filtering process could take up to an hour, so be patient! If you have any alcohol left over, pour it into the jar to ensure no leftover trichomes are remaining. Filter this additional solution.
The process works because the cannabinoids in the weed dissolve in the alcohol. The sieve filters the plant material, while the coffee filter refines the liquid by removing tiny parts of the remaining plant. As all of the cannabinoids have been dissolved, they are now in liquid form. The coffee filter enables liquid to pass through but prevents solid particles from doing so.
Once the filtering process has been completed, you are left with a jar containing a fairly clear liquid with a hint of green. Now, your precious THC is contained in the liquid, which means we must remove the alcohol.
Pour the contents of the jar into a container with a flat surface. If you have a fan, you can set it to blow into your liquid at its lowest setting. Please note that the alcohol must be stored in a well-ventilated area because you are evaporating a toxic and flammable substance. It could take up to 24 hours for the evaporation process to be completed.
The evaporation process is only completed when you see no traces of liquid on the flat surface. Get your razor blade and a clean mason jar, and gather the solid substance. A toothpick is a handy item to have as it can remove pieces of material that get stuck to the razor blade.
Don’t be dismayed when you see such a small amount of material. It should contain at least 70% THC (depending on the strain), and a little goes a VERY long way.
Final Thoughts on Using Rubbing Alcohol to Extract THC From Weed
The answer to the title question is ‘yes,’ but with a fair number of caveats. Firstly, you should NEVER use denatured alcohol as it is designed to be poisonous. If you are going to use rubbing alcohol as your solvent of choice, it must be isopropyl-based; ideally up to 99%.
There is a significant amount of confusion when it comes to distinguishing between different types of alcohol. Ethyl, or grain, alcohol is used in the recreational beverages that millions of people enjoy. Manufacturers denature ethyl alcohol by including poisonous substances which render the solution undrinkable.
Isopropyl alcohol, on the other hand, is already unfit for human consumption. Ingesting it can cause intestinal bleeding, vomiting, and occasionally, death. It is less toxic than denatured alcohol but is still poisonous to humans.
Therefore, if you insist on using isopropyl alcohol for THC extraction, extreme caution is advised. You need to ensure that all of the alcohol has been evaporated before using the leftover cannabis concentrate. It is a common solvent in DIY extraction, but we would recommend using food grade ethanol instead.
Once again, you need the ethanol to completely evaporate before using the concentrate. However, if you don’t remove 100% of the ethanol, and consume marijuana, you should not feel too many ill effects since ethanol is safe for human consumption. In fact, it is often used as an additive and food preservative.
Cannabis extractions with alcohol
During the last years, both extracts made with solvents and solventless concentrates have increased their popularity in an exponential way. This is due, in great measure, to the legalization process that is recently taking place in the USA, also to the creation of Cannabis Social Clubs in Spain.
In this post we present you two extraction methods for those who want to use alcohol as solvent (which will be later purged). We’ll see how to use ethanol (which we be the solvent used to illustrate this article) and isopropyl alcohol. Although both techniques have a very similar procedure, there are some differences worth taking into account which will be mentioned at the appropriate moment.
It should also be said that isopropyl alcohol contains more toxic substances than pure ethanol (which actually shouldn’t contain any). Thus, we recommend to use isopropyl exclusively to clean your utensils and glass pipes and not for performing extractions.
QWET extraction with ethanol
Cannabis extractions with alcohol
Known and practiced for many years, this type of extractions are quick and easy to perform. The theory is always the same: soak the plant matter in alcohol to dilute the trichomes in the solvent, i.e. in the alcohol. Once dissolved, we will have to remove the plant matter, filter the solution and purge the alcohol. Let’s take a closer look at the process.
Two types of alcohol are mainly used to perform these extractions: isopropyl alcohol or ethanol. We use ethanol because it’s much safer for our health. If we use isopropyl then the process is called “QWISO” (Quick wash isopropyl), while in the case of using ethanol we will talk about “QWET” (Quick wash ethanol). Why a quick wash instead of prolonged soaking? Why we don’t directly heat up the alcohol with the material to extract the greatest possible amount of cannabinoids and terpenes?
Mix of ethanol and buds recently removed from the freezer
The answer is simple: alcohol is a polar solvent. That means that if we use any of these two techniques, we’ll also extract other water soluble substances like chlorophyll or alkaloids. In this way, the first requisite is to use plant material as dry as possible. We can dry the material traditionally or in the oven at 90ºC until it crumbles when we press it between our fingers (heating the plant material enables the decarboxylation process of cannabinoids, which lose their acid form and become psychoactive without the need to be vaporized or burned to get you high. This is ideal to develop drugs or cook edibles).
As we oftenly recommend when making extractions, try to use first-class buds or trim and never grind the material prior to the extraction. In this way, the finished product will be much cleaner and therefore of greater quality. Once the material is properly dried, put it inside a storage jar with lid and then into the freezer. We have to do the same with the alcohol that we are going to use. When their temperature is stable around -17ºC, we pour the alcohol in the jar until covering the green material with 2-3 centimeters of alcohol.
Once the plant matter has been removed, filter the solution with a 25 micron mesh
Up to this moment, the process to make QWET or QWISO is the same regardless of the chosen alcohol. However, we find now a small variation: in the case of using ethanol (QWET), once the plants material has been covered with alcohol we must stir the mix gently to ensure that everything is well soaked and then put the jar in the freezer again. Wait for about 3 minutes, in which the mix should be stirred gently a couple more times. Then, pass the mixture through a strainer and/or a chinois to seperate the alcohol extract from the plant matter. When using isopropyl alcohol (QWISO), we have to stir the mix of buds and alcohol for 20 seconds and then strain in the same way.
We can keep the plant matter to let it dry and make a second run with alcohol or butane (BHO). Still, and as usual, the quality and yield of this second run will be lower than the first one. It is time now to learn how to separate the solvent from the extraction, either by using bain-marie or heat and vacuum.
Impurities collected in the 25 micron mesh
Purging the alcohol in cannabis extractions
We now have to filter the solution obtained after using the strainer. To do this, we can use vacuum and laboratory filters (around 40 microns), 25 micron resin drying screens (which is what we used) or simply pour the liquid through a coffee filter. We also used a Pyrex tray to collect the filtered solution; in this way we greatly facilitate the alcohol evaporation process.
Once the first filtering is done (a second filtering may be needed in some cases), place the tray in a water-bath (bain-marie) at about 70-80ºC until no more big bubbles of solvent are created. You can place four small “legs” under the tray so the warm water comes in contact with the greatest possible surface of the base of the container (you can use, for example, four metal caps). Then, filter again with a coffee filter and place the tray back in water-bath. This time, keep the container in bain marie until observing that the formation of small bubbles on the edges of the tray reduces drastically.
Purging the solution to remove the alcohol
If you don’t want the suspended particles to fall into the mixture, simply cover the tray with a 25 micron drying screen or similar. It will catch most of these particles while allowing the alcohol to evaporate.
At this point, and prior to the third and last heating process, we can gather the liquid to filter it into a smaller container for easier handling. Place it again in water bath for a few minutes and your QWET extract is ready!
Collecting the extraction
Vacuum purging of alcohol in cannabis extractions
If we have the equipment needed to vacuum purging our extract (heating plate, vacuum desiccator chamber and vacuum pump) we can use it to removee the alcohol from our extract. The process is very similar to vacuum purging BHO.
After the first water-bath, collect the extraction and place it on a non-stick surface. Adjust the heating plate at 40°C and place the extract in the vacuum chamber. Connect it to the pump, put the chamber on the hot plate and turn the pump on to start the process.
Vacuum purging a QWET extract
Once the pump starts working, the extract will quickly swell up like a soufflé. At this point, turn off the pump until the sample returns to its normal volume, when we can turn the pump on again. Repeat this process until it doesn’t swell anymore. Then, leave the vacuum working for at least 24 hours (this will depend on how effective has been the first purge with bain-marie, and of course how effective it is our pump).
We still should purge a little more
Always remember to perform all these processes following the corresponding safety measures, and away from flames or heat sources…