Dear Cannalovers, since many of you have asked us to enlarge the information regarding the differences between BHO and DHO, and some of you proposed us very interesting questions to discuss, we have decided to start working on it and tell you in a technical way, but at the same time simple, the secrets of these extraction methods, giving relevant information both to the sybarite medicinal consumer and to the professional producer of cannabis extracts
Let us not fool ourselves, both BHO and DHO are solvents or chemicals for extraction, so if you make the decision not to use solvents, this means that is not your technique; on the other hand both have many advantages if they are carried out correctly and the execution allows almost 100% of removal of the solvent used.
But Let’s go one step at a time…?
What is BHO?
The BHO stands for Butane Hash Oil, which comes from the product definition and the technique used, i. e. hashish oil extracted with butane gas.
Most of you are used to thinking about extraction solvents that are already liquids at room temperature. In the case of butane it is a gas at room temperature, but with high pressures we get the liquid gas to flow through the vegetable matter we want to extract.
This is a part of the basis of the BHO technique, the use of high pressure butane that makes it flow as a liquid through the marijuana sample.
Why is butane used?
That’s the other part of the technique. The polarity of the solvent.
The polarity of the solvent is its ability to dissolve or remove components that are of the same nature. For example, water that is very polar, dissolves very polar substances such as mineral fertilizers based on potassium nitrate, or calcium phosphate, which we have already treated in other posts.
In the case of butane, it is a very apolar substance (as opposed to water), this means that it dissolves very well substances soluble in fat and insoluble in water, such as cannabinoids and terpenes.
Butane, being a high pressure liquefied gas, is depressurized when passing through the sample, so that hashish oil bubbles at room temperature, that is to say, it is used that the gas has a boiling point of 0 º C at atmospheric pressure. This allows the gas to be eliminated almost completely by heating slightly the hashish oil obtained by extraction.
How to make BHO?
There are low production devices for homemade extractions, and other more sophisticated equipment installed to be installed as pilot professional extraction plants.
In the homemade extractions, it’s very simple its execution, since we only need a Roller extractor BHO, assemble it including the Roller Extractor support tripod, introduce the sample, and insert the gas valve (Colibri gas cartridge).
The use of this gas, which is already prepared for extractions, assures us a high purity content in Butane, so that it has no mixture of isobutane, propane and isopropane like conventional butane gas cylinders that you all know.
Remember, once assembled the Roller extractor with its support tripod, you only have to add the sample (always micronized with a grinder) to the extraction tube, and press it well. The Roller extractor has several sizes, but with all of them the technique is exactly the same.
I advise you to protect yourself, using special cold gloves, because when you depressurize the butane gas, the tube of the Roller extractor freezes below -20ºC and you will not be able to hold it.
Another essential advice is to make the extraction in an outdoor place, away from ignition points or electrical outlets, to avoid any spark of static electricity, as it’s an extremely flammable gas.
Also, use a mask equipped with an active carbon filter to avoid breathing butane gas as it bubbles in your collector tray.
Butane itself is not a very toxic gas, but breathing it at high concentrations can alter the absorption of oxygen in our lungs, also accumulates in the body’s fat, remember that it is very soluble in fats. Better to avoid it.
With respect to the pilot plant devices for extraction with BHO, we can find equipment such as these::
With which most of the butane can be recirculated, leaving a clean extract with undetectable gas impurities.
Now we go with DHO….
What is DHO?
The DHO stands for Dymetil ether Hash Oil, which comes from the product definition and the technique used, i. e. hash oil extracted with dimethyl ether gas.
Like butane for BHO, dimethyl ether or DME, is a gas at room temperature, in fact its boiling point is at -24.80ºC, which being lower than butane makes it easier to remove afterwards at room temperature. This is DHO’s first advantage over BHO.
DME is a molecule whose formula is identical to ethanol (or ethyl alcohol), but changes the rearrangement of its atoms, with this I simply mean that it weighs the same as alcohol, but behaves differently as a solvent. Also tell you that DHO is like liquid ethanol, more polar than butane and more manageable than butane.
In fact, being somewhat more polar than butane, final extractions with higher concentrations of terpenes have been found in the hash oil obtained, also preserving higher levels of cannabinoids than for BHO extractions.
How to do DHO?
Exactly like with the BHO. Since both DME and butane are highly flammable gases (the DME a little less), and with some toxicity, so the precautions to treat one and the other are the same.
Although DME is less flammable than butane, it also requires similar precautions, but keep in mind that in this case the gas we will use for homemade DHO extractions is the 500 ml Dexso DME.
The extractor that we must use is like the Roller extractor for BHO, but a little more sophisticated, since it is made up of aluminum and glass parts, without rubbery material, which can be easily dissolved by the gas. This is why they are more expensive extractions than you can perform with BHO.
Infographics on the main differences between BHO and DHO extraction
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Tips for BHO and DHO extraction
If you’ve decided to make your own hash oil extraction you have to take into account that the cannabis flowers must be freshly harvested, because this way we will obtain an oil very rich in terpenes providing an extraordinary flavor.
With the BHO procedure it is sometimes better to freeze the flowers on the same day of harvest and have them frozen for at least 24 hours. Keep in mind that the older the vegetable raw material is, in our case, the flowers, the less terpenes are extracted, because the terpenes evaporate slowly during the entire drying process.
With the DHO procedure it’s not necessary to freeze, since the extractions produced with DME are extraordinarily quantitative, and it is a more apolar (or less fat soluble) gas, which extracts all compounds whether they are in the trichomes or not, in a very effective way and at the same time.
We should not forget that by expanding the gas inside the extraction tube the vegetable matter is directly cryonized, thus, it could be better not to pre-treat the sample, unless we want to keep it for weeks, for which reason I recommend to keep it in vacuum bags and then store it at -20ºC
If the previously micronized flowers are compressed inside the extractor the yield will be higher, as well as the efficiency of the solvent, although we must be careful in the crushing, since if we destroy a great part of the glands we will be losing yield
The dimethyl ether evaporates rapidly due to its low evaporation temperature (-24.8°C). This speeds up water condensation in the extraction tube
It’s possible to help eliminate the gas once the extraction is done in the case of homemade extractions, so that we can evaporate the ether/butane by putting the container with the extract in a bain-marie. The temperature of the distilled water should be around 25ºC-30ºC; this causes the DME to evaporate almost instantaneously, it takes a little longer to remove butane.
After extraction, the oil can be diluted in alcohol with a minimum of 96% purity to make creams or tinctures, or in olive oil or hemp seed oil to make sublingual oil or also for topical use.
And after extraction??
Some of the solvent-extracted substances, such as waxes, have no medicinal or beneficial properties, and although these solvents extract less undesirable matters than supercritical CO2, we can concentrate cannabinoids even more after extraction with BHO or DHO.
These waxes precipitate at low temperatures when dissolved in alcohol. They end up forming particles that can be removed with a filter. The mixture of alcohol and extract is introduced in the freezer for 24-48 hours, so that the waxes begin to agglomerate and form white flakes that float in the solvent, this process is called “Winterization“.
The mixture is filtered with a coffee filter. After filtering the purified mixture, the alcohol evaporates. What remains is an oil that still contains small amounts of alcohol and water. But they can be easily removed with heat treatment. The vacuum pump allows alcohol and most moisture to evaporate completely.
Keep in mind that the extraction process always involves certain risks, so if we use BHO or DHO, it must be carried out outdoors, or with a special gas extraction equipment, away from any source of heat, flame or sparks. And, of course, before getting down to work, you have to be very well informed about the technique that you are going to use, consult the manufacturer’s manual of the extraction equipment that you are going to use if you have finally decided to install some professional equipment.
Good luck with your extraction… and remember to comply with safety regulations for handling equipment and gases!
At PEV Grow we hope that most of your doubts regarding the differences between BHO and DHO have been solved, although you know that if you need us, our technical department will solve any concept for which you need to deepen.
Surely you are going to become experts in extractions, and some of you will see yourself lifting some cannabic award in the coming months…. if so, don’t forget to share your experiences….…
We want to meet the next champion!!… … Do you dare to apply for a BHO or DHO cannabis cup?
In the next post we will tell you how to make marijuana milk; a product that will leave your best pastry recipes which will make to lick your fingers… and more!
See you in the next post!?