Butane hash oil (BHO) extraction

Do not perform this procedure indoors.

Due to the explosive nature of the solvents involved, attempting this procedure in underventilated areas (e.g. such as a small apartment room or basement) can result in serious injury, death or the destruction of property.

Disclaimer: This guide is provided for informational and educational purposes only. We do not encourage you to break the law and cannot claim any responsibility for your actions.

This is a tutorial for the extraction of hash oil from cannabis using liquid butane (commonly referred to as B.H.O). The aim of this tutorial is to provide a simple, straight-forward and risk-minimized procedure for the producer to produce a personal amount of hash oil in an outdoor environment. It has been deliberately designed to use the simplest, most accessible materials and equipment typically available while keeping the safety of the extractor (and local environment) in mind - for this reason, performing this extract indoors is inherently dangerous and should not be attempted.

Despite the simplicity of the extraction, it still requires some more advanced technical equipment such as a vacuum pump, and should not be performed if one cannot afford or acquire these things. This process is ideally conducted in a professional or lab environment and conducting them in home settings is generally inadvisable due to its high-risk nature. It is provided solely for educational and harm-reduction purposes only.

Risks and Hazards

Flammability of Butane

Butane is a flammable gas that has no odor and accumulates indoors and in unventilated areas. The accumulation of enough butane gas in an area presents a significant risk of sudden, unpredictable explosions, which can be lead to fires and fatal injury to the use. Therefore, utmost care and caution must be used when working in an environment that involves the use of butane gas.

Butane gas is highly flammable.

It should be noted that performing this extraction indoors significantly increases the risk of fires, explosions, and physical harm. Outside of a fully functioning fume hood, the production of BHO indoors carries with it a great inherent risk for explosions and bodily harm. While one may personally know of successful experiences of producing B.H.O. indoors, this should not be taken as evidence of this safety, given the large elements of chance involved.

While butane is a flammable gas, in order for an explosive event to occur there needs to be an ignition source or spark. This spark can come from common sense items such as a lighter or pilot light on a stove, but sparks can also occur in less obvious ways. Electric sparks can be created simply by wearing clothes - the common "shock" one experiences after shuffling around with socks on and touching a metal object, along with the sparks created by the compressors in most common kitchen freezers, is sufficient to cause an explosive event.

The flammability of a gas depends on its concentration in the atmosphere. The butane concentration must fall between an upper and lower limit to be able to ignite. The lower limit of butane concentration in the atmosphere is 1.89% and the higher limit is 8.5%. If the concentration of butane falls in this range and there is a spark present, there will be an ignition and an explosive event.

The "Well-Ventilated Area"

A "well-ventilated area" is commonly used to describe the area that is ideal for butane extraction. Contrary to popular belief, however, a "well-ventilated area" is not simply a room with all the windows open, it is not a kitchen stove top fan turned on, it is not a garage with the door open to let some air in - these areas do have ventilation, but the movement of air is unpredictable and may lead to explosions if butane does build up in the room. To be well-ventilated, an area must have a constant and steady supply of fresh air flowing through the area.

It should be noted that performing a B.H.O. extraction in a "well-ventilated area" does not eliminate the flammability and explosion hazard associated with the process, it only lowers this risk. It is always safer to do outdoors (provided one take the proper precautions, however, such as acquiring a fire extinguisher and related safety materials in advance).

Frostbite/Extreme Cold Hazards

When a gas expands it takes in heat from the atmosphere. When the liquid butane travels through the extraction tube, it expands as a gas and greatly reduces the temperature of the glass extraction tube. It is imperative to wear cold resistant safety gloves or handle the extraction tube with a tong apparatus to avoid contact with freezing temperatures that may cause harm.

Equipment

• Ground cannabis - You can make batches with as little material as you like although it is recommended that at least a half ounce be used for technical and economic reasons. The yield is highly dependent on the strain, batch and overall quality of the material.
• Filtered butane - Butane is available in a variety of grades dependent on how many times it has been filtered for impurities. Generally speaking, the more times it has been filtered, the better, but at a certain point additional filtering something more times isn't going to make a qualitative difference, so be mindful of diminishing returns! There also exists n-butane and other blended gas solvents of various kinds. These are typically much more expensive but are thought to increase the quality of the end product. All gaseous butane solvents are highly flammable.
• Extraction tube - Thick glass is preferred due to the reduced probability of chemical leeching and byproducts associated with plastic equipment. Thick glass can also handle the freezing/heating cycles present in this extraction better than other materials.
• Vacuum chamber and pump - A single stage pump is sufficient. Be wary of shorter chambers as the oil might bubble high enough to touch the lid.

A two gallon vacuum chamber and pump apparatus.

• Coffee filter and rubber band or hose clamp - Be careful not to rip the coffee filter, especially when it is wet! It is recommended that there are multiple coffee filters used to attach to the bottom of the extraction tube, so have plenty on hand.
• Pyrex baking dish - This should have a large surface area to increase the evaporation rate of the solvent.
• Protective gloves and mask - This is needed to protect against the frozen tube and butane vapors, both of which can cause bodily harm - Wearing the proper safety equipment is imperative for properly performing a B.H.O. extraction.
• Heat source - Avoid any open flame heat sources and heat sources that can cause flammable sparks as butane is unpredictable, highly flammable and explosive! An induction hot plate is a viable heat source option, as is any non-sparking, flame proof electrical heater or a simple water bath. If using a hot water bath, make sure to monitor the temperature and set it up over an induction heat source that does not have a pilot light.
• Fire extinguisher - This can make the difference between life and death if a fire or explosion occurs. Always have a fire extinguisher or fire blanket on hand in case of fire.
• Parchment paper or slick mat - This is used to pour the B.H.O. into after the purge step, to be placed in the vacuum chamber.
• Laser thermometer - This greatly aids in monitoring and controlling temperature.
• Dehydrator - This is an optional piece of equipment that can dehydrate the cannabis before the extraction procedure.

Procedure

Initial Steps

1. Break up (not grind) the cannabis into small and loose pieces. This increases the surface area for the solvent and maximizes the amount of material to be extracted.
2. Pack your extraction tube in a firm manner. Be careful not to over pack the tube full of cannabis as the butane must be allowed to flow through the material freely by the force of gravity.
3. Cover the open end with four coffee filters and secure with rubber band or clamp. This is imperative to prevent the plant material from exiting the extraction tube along with the butane.
4. Freeze your filled tube in your freezer in an air-tight container (this minimizes condensation) for a minimum of 2 hours.
5. Once frozen, put on the protective gloves, mask, and any other protective equipment and remove the tube from the freezer. Proper protective wear is imperative during this step.
6. In an outdoor area, prepare the pyrex tray that will be used to catch the liquid butane exiting the extraction tube. Place the pyrex or glass dish in a WELL ventilated space, which is only truly achievable outdoors or under a fume hood. This step is vital to ensuring a safe and explosion proof extraction process.
7. Begin pouring the butane into the extraction tube filled with cannabis from the small vent opening on one end. The butane should flow through the cannabis material to the bottom of the tube and fall into the pyrex dish. Due to the expansion of the liquid butane into gaseous butane, there will be a temperature drop within the tube. The tube will become very cold or frozen and impossible to hold without heat-resistant gloves or test tube tongs meant for extreme temperatures.
8. Continue to pour the butane into the extraction tube until the exiting butane lacks color and runs clear.
9. At this point allow most of your solvent to evaporate from the dish in the well-ventilated space free from mechanical or electrical sparks. Agitate occasionally at a safe distance. If using a hot water bath to aid in evaporation, monitor the temperature of the bath to keep it below boiling yet warm enough to aid in evaporation. Make sure to have a fire extinguisher near by in case of emergencies.

Final Steps

1. Once most of the butane has evaporated from the extraction trays, pour the liquid extract onto parchment paper or an oil slick and place it into the vacuum.
2. Turn on the vacuum and allow to reach full vacuum capacity which is typically around 29 in/Hg at sea level. The oil will begin to bubble and muffin up as the trapped butane escapes the extract into the chamber.
3. Wait several hours for the muffin tops to fall and the bubbles to stop forming. This activity signals that butane is exiting the B.H.O. as intended.
4. Once the activity has stopped place the chamber on the heat source and gently raise the temperature to 100-120 degrees Farenheit. Be very careful not to add too much heat as this will burn off terpenes and darken the end product. Wait for any remaining bubbles to stop and remove it from the vacuum.
5. Carefully try to flip the oil and melt it into the thinnest layer possible. Again take care not to add too much heat or fold air into the product as this will add moisture and trap in gasses which will affect the translucence and smoothness of the end product.
6. Place the thin layer of oil back into the chamber at full vacuum. Leave on overnight.
7. Repeat the final five steps as many times as necessary to fully purge the oil of impurities.

• 
  Ground Flower
• 
  Packed Tube
• 
  Frozen Tube
• 
  Butane Evaporation Process - make sure this is done in a well ventilated area.
• 
  Vacuum Chamber
• 
  The Purge Step
• 
  Final B.H.O. Extract

Notes

• Oil making is highly dependent on the strain. A wide variety of different looking products can result from this tek and may range from 'shatter' (the highest grade) to 'crumble' to 'wax' or anywhere in between. High THC strains often tend to "sugar up" and is prized by many for the smoothness of its vaporized taste.

External Links

_{The information contained in this article was acquired and accumulated from the sources below and should in no way indicate that the author or authors have any practice in illicit activities.} Salem (talk) 13:59, 12 January 2015 (UTC)

• https://skunkpharmresearch.com/bho-extraction/
• https://skunkpharmresearch.com/vacuum-purging-and-processing-tips/
• https://learnpot.blogspot.com/p/equipment-fire-extinguisher-safety.html