How to make hash with CO2 or dry ice

Hashish, as we all know, is a by-product of the cannabis plant. It?s the concentration of resin glands that are attached to the cell walls of cannabis buds.

There are different cannabinoid extracting methods, either with dried - like Dry Sift or Water Hash - or fresh plant material - Nepali Charas, Fresh Frozen. In this way, several resin extraction methods have been created depending on the needs and preferences of growers who want to enjoy their own creations for personal use.

In this case we present you a resin extraction method using Co2 - also known as dry ice - a technique derived from the classic dry sieving method.

Preparation and needed materials to make hashish with dry ice

Before getting started, you should prepare all the needed tools for the extraction with dry ice. We don't need much stuff to make extractions with CO2, although quality materials are always necessary for best possible results.

Materials to use
Materials to use

First of all, we obviously need the base material, our homegrown cannabis buds. After few months taking care of the plants, avoiding any possible issue or pest that could reduce the final quality of the crop, it is time to get the most out of them. As always, remember that top grade concentrates come from properly grown marijuana.

Cannabis remains for use
Cannabis remains for use

Secondly, we need Ice-o-Lator extraction bags or similar. These bags are exactly the same than those used for resin extractions with water and ice. In this case, and if you have different bags of different screen sizes, you should start with a 120 to 160 micron bag (depending on strains and needs) and gradually reduce the screen size according to the gland concentration you want.

As we have already explained in other posts, there are different types and sizes of trichomes. The morphology of these glands mainly depend on plant genetics, so we can find glands of up to 160mc and others measuring even less than 25-50mc.

Checking the condition of the material before its use
Checking the condition of the bag before its use

To obtain a clean and professional extraction, you should try to recover those glands measuring between 70 and 120mc, which normally yield the best quality. If the screens are smaller then the collected glands with the dry sift extraction will also be smaller (the used screen size mainly depends on user preferences).

The third element is the dry ice or CO2, the solid form of carbon dioxide. This product isn?t very difficult to find, but it is difficult to carry and store. You can buy it easily and quickly on the internet at companies who work with frozen or cold materials and deliver them at home.

The main problem with dry ice is that it degrades fast when not stored under very special conditions, so we'll have to use it as soon as we get it.

Dry Ice packed in porexpan
Dry Ice packed in expanded polystyrene

This is the main reason why it?s essential to have everything ready for a quick use, since we must use the solid CO2 as soon as we get it, otherwise it will quickly evaporate.

We will also need a plastic cup (to catch and pour the dry ice) and waterproof gloves to avoid burns: always remember that CO2 can cause severe burns in those parts of the body exposed for a few seconds to it.

How to use dry ice for cannabis resin extractions?

The first step will be to take the plant material out of the freezer  freezing it isn?t really required but recommendable) so when the organic matter goes in contact with the dry ice the resin glands are released easier and faster than with plant material at room temperature, thus achieving better yields and quality.

The second step is mixing the marijuana with the dry ice into a container (made of any non-toxic material which does not degrade with cold temperatures) and gently mix it a bit. We can now take our 120-160mc Ice-o-Lator or Cristalizer hash extraction mesh and pour the mix inside it. The amount of grass to be used may vary, depending on both the bag size and the needs of the grower.

Mixing the dry ice with cannabis
Mixing dry ice with cannabis

It?s possible to make a large extractions in one go, although using around 20-30 gr and gently sieving for no more than 15-20 seconds is recommended to get top grade hashish.

If the buds are large and compact, we'll gently crumble them in smaller buds to increase the plant surface in contact with the dry ice. In this way, and without grinding the flowers, you reduce the amount of plant debris that could contaminate your resin.

Once we have a smooth and clean surface prepared (PTFE film, glass, parchment paper, etc) and the dry ice with the buds inside the Ice-O-Lator bag, we can start shaking the bag gently and slowly for a few seconds. We'll see how the resin glands fall through the screen.

First big run of resin extraction
First run

The duration of the extraction mainly depends on two aspects: type of glands - some glands are more easily removed than others - and the desired quality - the more we shake, the lower the quality.

Most growers make a fast first extraction to collect the best trichomes, and then perform a second run adding more ice in order to recover more resin. Normally, this second run is more contaminated with plant debris than the first one, since plant matter is gradually shredded as we shake the bag.

Changing the mesh to make a new extraction, with the already used remains.
Changing the mesh to make a second run

Once you have the resin on the surface, it is time to collect it with a card for proper storage. Notice that, unlike happens with hashish made with water and ice, we don't need to dry this resin, so we can taste it instantly.

Still, it should be noted that due to the condensation of the ice the resin can get sometimes a bit moisturized during the extraction process, so letting it dry completely for few hours would be ideal. We can dry it with a heating mat at around 37 °C, a good temperature for resin curing.

Gathering a 2 minute extraction
Collecting resin glands

Extraction with dry ice step by step (First run)

1. Prepare all materials: dry ice, dry cannabis buds, ice-o-lator bags, waterproof gloves, clean surface.

Frozen cannabis with dry ice
Frozen plant material

2. Mix the marijuana buds and the dry ice and let it rest for few minutes so buds are completely frozen.

3. Pour the mix into the sieving bag.

Extraction with dry ice
Cannabis buds with dry ice

4. Gently shake the bag to start removing glands: for this run we just need to remove the best trichome heads, so we should stop shaking before contaminating the extraction with plant debris.

2ond pass without mesh filter 40s
The first resin glands are sieved

5. Collect the resin and repeat the extraction process for another 20-40 seconds (second run). You can repeat the process until you see the first signs of plant matter.

Gathering the 2ond extraction
Collecting the 2nd run

6. Finally, we made a total of 8 runs with the same screen size and different times of extraction: 5, 15 and 40 seconds.

3 grades, same extraction time
3 different grades, same extraction times

7. Let the resin rest on a heat mat to evaporate any remaining moisture from the condensation of dry ice when it changes to gaseous state.

Drying the extraction at 34ºC near an optimal temperature of 37ºC
Extraction drying at 34ºC

Second extraction with another type of cannabis

In this second extraction we have slightly varied the method and times to observe and show you the differences. Once we have prepared the materials to use for the extraction:

1. Mix the cannabis and the dry ice in a bowl to freeze the weed and the glands in order to make the extraction easier.

Freezing the weed during 2 minutes
Freezing the weed during 2 minutes

2. Pour the mix of dry ice and marijuana buds into an Ice-O-Lator extraction bag and shake for 2 minutes with care to avoid producing too much plant debris.

3.Collect the resin glands with a card and store it. You can press it  with a manual hashish press .

Trichomes joins quickly
Trichomes being collected

4. Continue with the extraction if you want to get the most out of your plant material. This run will have much more plant debris than the first one.

Second extraction of resin with plant matter but with glands
Second extraction, much more contaminated with plant debris

5. Collect the extraction with plant matter (don?t mix it with the first one!)

Hash with a lot of plant matter
Hash with a lots of plant debris

Gathering the outcome of the 2ond pass with plant matter
Collecting the second run, much more contaminated

Conclusions of the extraction with dry ice

First of all, this method is not very popular due the price of dry ice, which is around 50-60? for 5 kg. The ideal would be purchasing the ice with other growers so everyone makes his own extraction, since we really don't need 5kg unless we have lots of buds.

The amount of plant material used can vary; you can use about 1.5 kg of dry ice for every 60gr of dried buds. After 2-4 minutes of use, only a small part of dry ice had evaporated.

At the left, 1rst extraction of glands, at the right 2ond extraction of glands and plant matter.
Left: first run Right: second run

This extraction method offers very good yields, being perfect to easily and quickly make a nice, standard quality hash piece. While it is true that the most experienced growers in resin extractions claim that this is not the ideal method for getting the highest quality, it is truly an appropriate method to make large amounts of standard grade hashish with just a 160 micron mesh anf few minutes.

Product of the extraction with plant matter in a second run after 4 min. and a mesh of 185mc
second run, 4 minutes, 185 micron mesh

1rst extractión 2 min and gathering
1st run, 2 minutes

8 different types of hash extractions of different times
8 different hash grades

Detail of the 3rd run of extraction of 40 sec
3rd run, 40 seconds

Precautions for handling CO2

Using the correct safety measures is important if we want to avoid problems.

Dry ice reaches temperatures of (-74ºC / -42.5°C) or -109.3F, so using waterproof gloves to avoid burns on your hands is absolutely necessary. Dry ice is really cold!

Also, use safety goggles to avoid contact with your eyes.

The articles published by Alchimiaweb, S.L. are reserved for adult clients only. We would like to remind our customers that cannabis seeds are not listed in the European Community catalogue. They are products intended for genetic conservation and collecting, in no case for cultivation. In some countries it is strictly forbidden to germinate cannabis seeds, other than those authorised by the European Union. We recommend our customers not to infringe the law in any way, we are not responsible for their use.

Comments in “How to make hash with CO2 or dry ice” (4)


Simon Is an Alchimia client 2022-10-15
Can I use buds with seed for this method

Alchimia Staff

Tim Alchimia 2022-10-17
Hi Simon, thanks for your comment and question. CO2 solvent extraction is commonly used in the food industry to extract vegetable oils from seeds, so I would expect to get some contamination of the cannabis extract with seed oil as a result of the extraction process. The dry ice method, on the other hand, is basically a super-cold dry sift technique so is very unlikely to have th same issue although it tends to produce a much "dirtier" hash with considerable amounts of leaf matter contaminating the resin. In my opinion, the best technique in terms of quality to use with seeded buds would be either to make dry sift or ice water hash. I hope that helps, best wishes and happy hashing!


Chase0420 2020-10-05
Can you explain making hash from freshly cut down plants? You speak of fresh frozen but nothing about freshly cut down plants. Im needing to process fresh material because i had a very aggressive aphid issue. Anything that might help with this issue would be greatly appreciated!

Alchimia Staff

Tim Alchimia 2020-10-06
Hi, thanks for your comment and question. Fortunately, we have a blog article dealing with exactly this subject! Here it is: "Fresh chilled cannabis to make water hash". I hope that helps, if you have any further questions you can leave a comment on that post. All the best and happy hashing!


Llewellyn 2019-09-10
I'm just getting started here- Should the buds be dried first? Should they be cured first? Last, what is the result of using fresh harvested?

Alchimia Staff

Tim Alchimia 2019-09-17
Hi Llewellyn, thanks for your questions. You can extract with C02 or Dry Ice from dried material or from freshly cut material, although fresh material will need more care and gentle treatment to avoid contamination with vegetable matter from the brittle pistils and leaves. It may be easier to use dried material for your first attempt and progress to fresh-frozen once you've got the hang of it, but that's your call. I wouldn't recommend using cured material if it can be avoided, curing is essential to be able to smoke the flowers, but less so for hash, and if you want to smoke cured hash, it's best to cure the finished hash rather than the starting material. The advantage of using fresh material, apart from saving drying time, is that the end results are much more aromatic and terpene-rich than when using dried material. I hope that's helped, all the best and happy hashing!


Robert E Florent Jr 2016-03-04
Please keep me updated on any information you publish on marijuana, cannabis and hash. I would also like to know how to make liquid marijuana, I can smoke in a vaporizer. Thank you for listening

Alchimia Staff

Dani Alchimia 2016-03-04
Hi Robert, Stay tuned to our blog, we are preparing an article on how to make cannabis e-liquids for vaporizers. Thanks for your confidence, All the best!

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