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What is Bubble Hash?

Bubble hash, also called ice water hash or ice hash, is one of the most popular cannabis concentrates on the market today. When produced under the right conditions, it offers unrivaled quality and potency among hashish products. For cannabis business owners and extraction labs, bubble hash presents lucrative opportunities. But exactly what is bubble hash?

Finished Bubble Hash In Container

Finished bubble hash made by Papa's Select (Instagram: @papas_select)

An Overview of Bubble Hash

Bubble hash is a type of hashish that’s made using an ice water extraction process. It gets its name from the tiny bubbles that appear as the concentrate melts.

Top Tier Melting Bubble Hash Greasing Up In a Jar

Bubble hash "greasing up" after being left at room temperature.

Although hash has a history that dates back to 11th century Persia and Arabia, extraction methods have traditionally involved manually separating the trichomes (the terpene- and cannabinoid-rich resin glands) from the plant and compressing them.

It was in the late 1980s when David Paul Watson, better known as Sadhu Sam, popularized the notion of “hash washing,” or using water to separate the trichomes from the plant material. Because the trichomes are rich in oil, they sink to the bottom of a water-filled vessel while the plant material floats to the top. Mila Jansen, or Mila the Hash Queen, later fine-tuned this extraction method in the late ‘90s with the use of ice and filter bags (commonly referred to as bubble bags). Since then, other innovators have improved the method even more, allowing for greater potency and precision.

Today, hash is typically divided into one of two categories: dry sift (or just “sift”) and bubble hash. Sift is the traditional hash method whereby the trichomes are isolated by hand or via mechanical separation. Bubble hash refers to hash that’s produced using the ice water extraction process.

Bubble Hash vs Sift

To break it down a bit further:

Dry Sift Hash

Dry sift is most commonly extracted from the cannabis plant using 90μm to 220μm sifting screens. The collected kief can then be compressed into blocks or cakes using a pollen press.

Dry Sift Hash being Prepped

Dry sift hash

While this is one of the simplest and most cost-effective ways to make cannabis concentrates at home, it’s not very efficient for professionals who need to extract large volumes of sift with precision. In these cases, it’s more practical to use a machine trichome extractor like the Alchemist 420.

Bubble Hash

Bubble hash is generally preferred by connoisseurs in today’s concentrates markets. That’s because it’s generally higher-quality, it contains less plant material, and it’s less prone to surface contamination during production. As a result, bubble hash often melts better than sift and is generally more pure and flavorful.

Sieved Bubble Hash On Trays In Cold Room

Freeze dried, sieved bubble hash

While it is possible to produce full-melt sift that rivals bubble hash in quality, it’s extremely difficult to achieve. For extractors looking to achieve the maximum quality with consistent results, bubble hash is the way to go.

How Do You Make Bubble Hash?

While the nuances of making bubble hash can vary, the basic process is as follows:

1. Choosing a Starting Material

To make a high-quality hash, you want to start with a trichome-rich cannabis strain. Certain strains—like Chemdawg, Gorilla Glue, and Papaya—are known for their robust trichome assortments, but quality can vary by batch even when you’re relying on the best of strains. That’s why you should be able to identify hash-friendly strains and batches individually. Refer to our complete guide on How to Identify Strains for Solventless Bubble Hash.

Fresh Frozen Cannabis Flower

High quality fresh frozen starting material 

You’ll also have to determine whether you want to use dried and cured or fresh-frozen cannabis. Many top extractors use fresh frozen while others regular cannabis flower that has been dried and cured. This is the simplest and most cost-effective way to go (particularly if you don’t harvest your own plants), but the curing process does sacrifice a significant amount of terpenes. By freezing your plants in their fresh state and processing them into bubble hash immediately while still frozen, you can achieve a higher-quality “live” product with a richer terpene profile.

To learn more about fresh-frozen cannabis, refer to our guide on How to Process Flower From Harvest to Fresh Frozen.

2. Agitating the Cannabis

The first step in making ice water hash is to submerge the cannabis in a vessel filled with ice water. The ice water is stirred continuously to loosen the trichome heads and separate the resin from the plant. This step is typically completed with a basic hash-washing vessel or a complete hash-washing system.

Washing Bubble Hash in Bruteless Vessel

Agitating fresh frozen cannabis in a Bruteless hash washing vessel

The agitation is traditionally done by hand with a paddle or other stirring device. New technologies, though, have paved the way for automatic agitation. For instance, devices like the Axis Trichome Separator allow extractors to put the agitation on autopilot thanks to a motorized paddle that lowers into the wash vessel and spins at a constant, preset speed. This makes it easier to process multiple batches of ice water hash simultaneously.

3. Filtering the Cannabis

After the trichomes have been separated, they must be filtered to remove unwanted cannabis plant matter, preserving only the resin. The simple method is to drain the water from the agitation vessel into a second filtration vessel below. The filtration vessel is lined with layers of mesh stacker bags, through which the hash is filtered before being collected.

Filtering bubble hash process in bruteless system

Bubble hash filtration

Thanks to recent innovations from PurePressure, some businesses are upgrading from gravity filtration to pump filtration. This system still uses separate agitation and filtration vessels, but the vessels are connected via hoses and the water moves through the vessels with the help of a pneumatic hash pump. This type of system accommodates lower ceiling heights and allows for better batch-style processing. When you add a centrifugal pump, you can even recirculate the water.

Collecting wet bubble hash onto freeze dryer tray

Collecting wet bubble hash on trays for freeze drying

4. Drying

After the filtered hash is collected, the residual moisture must be removed. This is best achieved with the help of a freeze dryer. Whereas traditional freezers lock in moisture, freeze dryers use a low-temperature dehydration process to remove the remaining moisture and preserve the integrity of the original product.

Freeze Dried Bubble Hash On Tray Being Broken Up

Breaking up freeze dried bubble hash

A typical drying cycle will last between 6 and 24 hours depending on the type of freeze dryer and the amount of product you’re drying. Labconco and Harvest Right freeze dryers work extremely well for bubble hash.

Dry bubble hash poured into container

Freeze dried, sieved bubble hash

Bubble Hash Ratings

Bubble hash is rated on a 6-point scale based on how well it melts when heated. A better melt indicates fewer impurities.

  • 6 stars is considered full-melt bubble hash
  • 5 stars is nearly full-melt or rosin-grade
  • 3 and 4 stars are considered half-melt or rosin-grade
  • 1 and 2 stars are considered food-grade hash

Many products advertised as “full-melt hash” are actually 5-star and not 6. It’s difficult to achieve perfect 6-star hash, but 5-star hash is still extremely high-quality and can contain up to 60% THC.

The best way to test the quality of a hash product is to melt it on a quartz nail. If there is no residue left on the nail, you have 6-star hash. If some residue is left behind, the amount of char will determine where your hash falls on the rating spectrum. Low-grade bubble hash will barely melt at all.

Can You Smoke Bubble Hash?

Five and 6-star hash lend themselves to a wide range of consumption methods. These products are good for both dabbing and vaping since they melt so well. They can also be used as bowl toppers, sprinkled over joints and blunts, and incorporated into edibles.

Half-melt (3- and 4-star) hash works well as a bowl topper and can be incorporated into edibles recipes, but it does have some residual plant debris—including fragmented leaves from the buds. So while you can technically vape or dab it, it will burn out much more quickly than full-melt hash and may not result in the same smooth experience.

Cooking-grade hash contains high levels of plant matter and is not recommended for dabbing or vaping. It’s best reserved for edibles, hence the name.

Making Rosin Out of Bubble Hash

Bubble hash can also be further processed into hash rosin. Rosin is a solventless extract that’s achieved using a combination of heat and pressure. Unlike traditional extracts, you don’t need a chemical solvent like butane, propane, or ethanol to isolate the desired compounds. Instead, the hash is placed between two heated plates on a rosin press, and the plates are pressed together with several tons of force. The resin is squeezed from between the plates and collected.

When working with bubble hash, you would generally set your rosin press to a temperature between 170°F to 190°F (though your preferences may vary). You’ll want to set the pressure to a range between 300 and 1,500 lbf. When pressing bubble hash, we recommend first wrapping the material in these 25μm stainless-steel mesh rosin screens for precise filtration. You’ll also want to line the plates with parchment paper or PTFE sheets to collect the material and reduce your cleanup effort.

Bubble hash on its own is an excellent product. But when you start with a high-quality bubble hash and extract it into hash rosin, you’re ultimately left with one of the cleanest and most potent extracts available. For extraction businesses, that can translate to massive profits.

Why Businesses & Consumers Prefer Bubble Hash

Bubble hash is a hot commodity right now.

 Lemon Royale Bubble Hash from Papas Select

Papa's Select Lemon Royale 120µm bubble hash (Instagram: @papas_select)



Consumers love it because:

  • It’s incredibly potent, rich with THC and other cannabinoids.
  • It’s a clean cannabis concentrate, with no solvents or foreign chemicals used in the production process.
  • It offers an amazing taste and aroma profile on account of the rich terpene content.
  • It’s a versatile product that can be dabbed, vaped, twaxed, or added to any number of infusions.

Extraction business owners love it because:

  • It appeals to a growing market segment that’s leery about the presence of chemicals in their dabs and vape products.
  • It appeals to discerning connoisseurs and can be sold at a premium.
  • It’s much more affordable to produce than solvent-based products, even if you take it a step further and make hash rosin. A large commercial hash-washing system can be purchased for as little as $10,000, and a complete set of solventless extraction equipment (including the rosin press, hash washing system, freeze dryers, and other essentials) can be purchased for as little as $60,000 to $100,000. That’s a fraction of what you’d pay for a solvent lab.

Ice water hash is here to stay, and savvy processors are already capitalizing on this growing trend. Are you?

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