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Making Marijuana Concentrate - Hash

Updated: Dec 2, 2018

What is Hash?

Hash, or hashish, is a marijuana concentrate made from the resinous glands (trichomes) of the marijuana plant. It differs from cannabis oil (aka, wax, dabs, etc.) because the trichomes are separated physically rather than chemically, and the bulbous heads and stalks of the trichomes remain in the finished product.

Hash is made by sifting marijuana leaf or flower with a screen or mesh which allows the trichomes to fall through and the plant material to be discarded. The resulting trichomes can then be further processed by pressing, rubbing, or just used directly as desired.

Overview Of The Process

Making hash can be as simple as dry sifting marijuana by rubbing it on a fine nylon mesh or screen, but a higher quality product can be made by honing the technique with some additional time and equipment. The process described here is called ice water hash, sometimes called bubble hash.

The ice water hash process, while an advanced technique, is still rather simple:

  1. Start with dry leaf or flower, frozen

  2. Suspend the material in ice water

  3. Agitate the mixture to break off the trichomes

  4. Strain the ice water through a series of successively smaller mesh screens

  5. Press the trichomes to remove excess water, then air dry

This process is somewhat time consuming, but the result is a very refined concentrate with no visible plant material other than the transparent husk of the intact trichomes.

The Process in Detail

Begin by freezing high quality, dry marijuana leaf or flower for at least 24 hours. High quality leaf is trimmed from high quality marijuana flowers. Do not use leaf without visible trichomes, leaf that has yellowed, or fan leaves from the stalks of the plant.

The equipment needed is minimal:

  1. Two containers of appropriate size for the filtration bags used (5-gallon buckets are frequently used, as many filter bags are made in this size)

  2. Set of nylon filtration bags (recommended micron sizes: 220, 160, 110, 73, 25) and hash pressing screen

  3. Strong stirring stick or rod (example: a 3/4 dowel or new broom handle)

  4. Paper towels

  5. Ice and tap water (bagged ice with sharp edges works better than smooth ice)

Place a layer of ice in the bottom of the container, add the frozen material, and cover with ice to nearly fill the container. Add cold water from the tap to cover the ice. Allow the ice water and marijuana mixture to chill, undisturbed, for 5-10 minutes before agitating with the stirring stick. Agitate the mixture vigorously for 20-30 minutes.

Filter the plant material and ice out of the mixture using the largest mesh bag (recommended micron size: 220, sometimes called the "work bag"). Do this by placing the bag in the empty container and pouring the ice water and marijuana mixture through it, then removing the bag of ice and plant material and discarding, leaving a layer of golden trichome sediment on the bottom of the second container. This is what will become your hash, after further filtration and separation.

Mechanical Agitation

Agitating this slurry of ice, water, and marijuana for sufficient time to remove the majority of the trichomes is the most tiresome part of the process. Many treatises suggest using drill attachments, mixers, or similar devices to speed it up, however this will break off fine pieces of plant material also, creating a concentrate with visible plant material.

Mechanizing the process without decreasing the quality of the product can only be done successfully by using a physical device capable of agitating the entire mixture without touching the plant material directly. There are products specifically designed for the task, but frequently, a new, portable washing machine is employed. Most of these devices will allow a 5-gallon, 220 micron filter bag to be filled with ice and material, tied securely, placed inside, then covered with more ice and chilled water. The drain hose of the machine is then placed into a container for further filtration and separation described below. This container must be able to hold the entire contents of the machine to avoid spillage of the valuable ice water and trichome mixture.

This agitation of the marijuana and ice in a vat of ice water is very effective, and a hands-off approach to high quality hash. Each machine is different, so experiment with settings to get the desired agitation time and proper container size.

Filtration And Separation

Whether you use a stir stick, hash machine, or washing machine to agitate the ice water and marijuana mixture, the final result is a container full of very cold water and trichomes that have been filtered through the largest mesh bag (recommended: 220 microns). These trichomes can be used directly or further filtered and separated to create finer "grades" of hash. This filtration and separation is accomplished by pouring the water and trichome mixture from container to container through successively finer mesh filter bags.

Most filter bags on the market have handy drawstring ties at the tops which allow the bags to be set aside and hung to dry until you have finished filtering and separating all of the trichomes and are ready for pressing. It is important to ensure that the water and trichome mixture stays as cold as possible during the filtration process, so it is recommended to filter and separate all grades first, before pressing.

Use a 160 micron filter bag to remove small particles of plant material that make it through the 220 micron filter (160-220 microns). The material trapped by the filter bag may be used or discarded, but has a much lower potency than the finer filters due to this residual plant material, and cannot be described as hash. It can be used effectively in bhang, tea, and other drinks and foods, however.

The first grade of hash is separated using the 110 micron filter bag (110-160 microns). While it may have some plant material remaining, the particles are very few and fine after filtration through the 220 and 160 micron filters, so this grade is very tasty and fairly potent for smoking, but is not quite pure enough for vaporizing.

The finest grade of hash is then separated using the 73 micron filter bag. This is the product that is frequently called bubble hash, because it bubbles when smoked or vaporized, similar to cannabis oil. This grade contains trichomes between 73 and 110 microns in diameter, which means it is made up of the heads of bulbous and capitate trichomes and contains very little, if any, plant material, trichome stalks, or cessile (hair) trichomes. The final product is very rich in essential oils and cannabinoids, and is very sticky when dry. The quality of this hash will be a direct result of the quality of leaf and flower used, and the handling during processing.

The final grade of hash is a fine, dark hash which is rich in trichome stalks and cessile trichomes (25-73 microns). Because of the metabolic pathways the plant uses to create cannabinoids, these trichomes are higher in CBC than the previous grades, which can be particularly helpful for insomnia and spasticity. The 25 micron filter bag is used for this grade, and the remaining ice water is nearly devoid of cannabinoid material and can be discarded.

Pressing And Air Drying

The final steps in hash making are pressing and air drying. These steps commence after all the ice water has drained from the hanging filter bags, and are required to remove the last bit of water introduced during the process. This ensures that the hash won't grow mold when stored, as recommended, in an airtight container. Ice water hash will grow mold if not dried properly before storage.

It is recommended to start with the 73 micron bag, as these trichomes are the most sensitive to heat, and will become sticky and unmanageable fairly quickly after draining.

First prepare two "beds" of 6-8 layered paper towels to absorb the expressed water - one to lay under the pressing screen and one to press down on the top. Place the pressing screen on the bottom bed. Scoop the trichomes out of the bottom of the filter bag and place on the pressing screen in a pile, then fold the pressing screen over the top of the pile. Place the top bed of paper towels on top of the folded pressing screen and gently press down on the top of the pile. This will squeeze the remaining water out of the trichomes, through the pressing screen, to be absorbed by the paper towels.

Lift the top bed of paper towels and move the pressed cake of trichomes to a dry spot on the bottom bed, and repeat this gentle pressing cycle until the pressure no longer creates a wet spot on the paper towels. Try to press fairly quickly, so that the heat of your hands does not warm the trichomes and make them sticky. If the pressed hash sticks to the pressing screen, this is an indicator that the hash is getting too warm, though the thinner outer edges of the hash "puck" sticking to the pressing screen is normal. Try to minimize sticking, while making sure to get all the water out of the trichomes. This is a balance that will be learned by experience.

After pressing, remove the puck from the pressing screen and break it or cut it into smaller (1/4"-3/8") chunks, spreading it out onto a paper plate for 24-48 hours of air drying, depending on the relative humidity. If the relative humidity of your drying area is above 40%, ensure a full 48 hours of air drying time to eliminate risk of mold growth. Store in an airtight container after drying to keep the hash fresh and tasty.


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