Ice Water Extraction 101 - Benefits & Factors to Consider

Ice Water Extraction

Ice water extraction is a solventless method of making cannabis concentrates that uses water, ice, and agitation. This method was developed and refined at the end of the 20th century and continues to be a standard extraction method for connoisseurs and extraction companies alike.

Ice water extraction has many benefits, including a pure and clean extract (bubble hash), no use of solvents, and no risk of burns as there is with the dry ice method. Extraction professionals who are interested in this technique need to understand the process, its benefits relative to the alternatives, and factors to take into consideration.

What Is Ice Water Extraction?

Bubble Hash product from ice water extraction

"Ice water extraction" is a cannabis extraction method that separates the trichome heads cleanly from cannabis buds and sugar leaves using water, ice, and agitation. A series of mesh filter bags collect the trichome heads when they detach from the plant material and fall to the bottom of the vessel.

"Extraction" in terms of cannabis refers to the separation of the trichome heads from the plant material for a more potent smoking or vaporizing experience. The trichome heads contain the cannabinoid and terpene-rich resin that gives the cannabis plant its signature aromas, flavors, and effects.

Ice Water Extraction and Bubble Hash

Once the trichome heads are collected and dried, the resulting extract is referred to as bubble hash, ice water hash, ice-o-lator, or even ice water extraction (IWE). The term "bubble hash" refers to the way this extract bubbles when dabbed.

The Ice Water Extraction Process

There are two main approaches to making ice water hash: hand washing and machine washing.

How to Make Ice Water Hash by Hand

You can make ice water hash (bubble hash) manually with a clean wash vessel, ice cold water, ice, cannabis flowers, and mesh filtration bags (bubble bags).

  1. Freeze your flower.
  2. Soak the frozen cannabis flowers in the ice cold water.
  3. Agitate the water with a hand paddle until the trichome heads detach from the plant material. These are typically 15-20 minute washes with four cycles in total.
  4. The trichome heads will fall to the bottom of the vessel and settle in one of the mesh bags according to their size. It's best to have one vessel for agitation and one for your filtration bags. This will result in cleaner hash.
  5. Scoop the collected trichome heads out of the mesh bags (separated by size) onto parchment lined trays. You can now choose to air dry or freeze dry your hash according to our guidelines on how to dry bubble hash.

How to Make Ice Water Hash With a Machine

Washing hash by hand is fine for beginners and hobbyists. However, you'll need professional hash washing equipment to produce high-quality ice water extracts at scale.

The Osprey™, for example, offers top-of-the-line features that you simply can't achieve when washing by hand:

  • The Osprey ice water extraction machine
    Stainless steel construction to prevent contamination with microplastics
  • Low shear impeller paired with a square vessel lets the water do the work (via a vortex) instead of contacting each bud with a blade on a top-down mixer
  • 75 gallon capacity—processes up to 21 kg fresh frozen material or 4.2 kg dry material per wash
  • Daily throughput of 185 lbs of fresh frozen flower for 121 lbs of solventless water hash with 4 cycles and only one employee
  • Ability to set custom recipes

Unlike top-down agitation solutions that risk introducing shear and contaminants due to constant blender-like paddle-material contact, our innovative design minimizes such issues, preventing hot spots and ensuring superior homogenization.

Important note: For best results with commercial ice water extraction, it's critical to use cold RO water. Our 300-gallon Chilled Water Skid can produce 300 gallons of potable water per day for clean, food-grade ice water extracts.

Benefits of Ice Water Extraction

Ice water extraction has several benefits compared to other solventless and solvent-based extraction methods:

Ice Water Extraction vs. Dry Solventless Extraction Methods

  • Ice water extracts contain less unwanted plant material than solventless extracts like kief, dry sift, and dry ice hash.
  • Ice water extracts are less likely to be contaminated with dust particles than their dry counterparts because the entire process takes place in water.
  • The higher purity and potency of ice water hash means that it can often be dabbed directly with no further processing needed.
  • Ice water hash can be made from fresh frozen cannabis, resulting in a "live" extract that contains almost the same terpene profile of the plant at the time of harvest.
  • Ice water hash is the best starting material for premium rosin.

Ice Water Extraction vs. Solvent Based Extraction Methods

  • Ice water hash doesn't undergo any purification or purging after extraction. Consumers can be confident that the starting material must have been top-grade if the extract passes quality assurance testing.
  • No solvents are required for the ice water extraction process. This makes ice water extraction more accessible for enthusiasts and small extraction companies that don't have the capital to invest in a safe, closed-loop solvent extraction system.

Factors to Consider

Solventless extracts like ice water hash have great marketing potential. You can sell bubble hash as-is, press it and sell hash rosin, or use the bubble hash to make infused edibles. In January 2023, bubble hash was the second most popular solventless product after rosin. With the right equipment, you can make both!

To ensure a product that has great shelf appeal and is capable of competing in the current cannabis market, keep the following points in mind:

Pre-Test a New Strain Before Washing

Not all strains wash well. Before you do a full run with a new cultivar, do a test wash with a mason jar to see if you get a decent amount of trichomes. 

  1. Place around 1 oz of buds in a mason jar. The buds should be the same size you’d use for a full wash (popcorn size but not ground).
  2. Fill the mason jar with ice cold water and some ice, leaving a couple of inches of space at the top.
  3. Shake the mason jar vigorously for 10-15 minutes.
  4. Allow the contents to settle.
  5. Observe how thickly the bottom of the jar is coated with trichomes.

Afterward, you can pour the plant material off the top, collect the trichome heads, dry them, and smoke them. However, just observing how many trichome heads detached and fell to the bottom of the jar will give you a good indication of the strain’s suitability for ice water extraction.

Use Fresh Frozen Cannabis

Fresh frozen or dried cannabis buds can be used to make ice water hash. However, fresh frozen will give you a live product that can fetch higher prices in dispensaries.

Use RO-Purified or Distilled Water

You must wash your buds in RO water to ensure you’re not introducing contaminants. Investing in your own reverse osmosis machine can help you scale without compromising on quality or cleanliness.

Extract the Trichome Heads in a Cold Environment

Cold temperatures are critical for a successful wash because they:

  • Keep the trichome heads brittle
  • Minimize cannabinoid and terpene degradation
  • Minimize chlorophyll leaching from the flower
  • Prevent the resulting bubble hash from greasing up

A cold room or a room with an air conditioning system would be ideal.

Use the Right Hash Washing Equipment

ice water hash product progress

Producing large quantities of ice water hash is a huge undertaking. Research and compare your options carefully before investing in hash washing equipment.

As we mentioned above, The Osprey has an extremely gentle impeller and creates the perfect vortex inside the square-shaped vessel. Don't risk your money on a sub-par machine that shreds your plant material or potentially contaminates your extract with microplastics.

Freeze Dry the Ice Water Extract

There are several options for drying bubble hash after extraction. We recommend freeze drying over air drying for several reasons:

  • Your dried bubble hash will be much lighter in color and hence have more shelf appeal.
  • Freeze drying protects the extract from contamination.
  • Freeze drying gives you full control over your drying parameters.
  • Freeze drying dries the hash patties completely, so there's no chance of mold growth from residual moisture.
  • Freeze drying often takes around 24 hours compared to several days for air drying. This allows you to get your product to market sooner.

Store the Dried Bubble Hash Correctly

Storing ice water hash correctly is just as important as optimizing the extraction process. Keep the dried hash in airtight containers in a fridge or freezer (depending on how long you plan to store it) until you press it for rosin or have it grammed out and transported to dispensaries for sale.

Create Premium Hash With a Great ROI

Commercial-scale ice water extraction is both accessible and lucrative with the right hash washing equipment. Get your strains, washing, and drying processes right and you should have a product that can hold its own in the competitive cannabis industry.

Ice water hash stands out in the extraction scene for its purity, potency, and accessibility for producers. Whether you plan to sell it as-is or use it to create premium hash rosin, this extract offers an excellent ROI.

Article written by

Levi Lanzrath

Levi Lanzrath is a cannabis extraction expert and founder of Lowtemp Industries.