The Complete Guide to Bubble Hash vs. Rosin

For anyone seeking to produce cannabis concentrates and extracts without the use of solvents, bubble hash and rosin are the premier choices. They are the two major solventless concentrates currently available, and both can be produced at home or commercially.

While both concentrates can be made at a relatively low cost and without advanced chemistry knowledge, these two products are a world apart in terms of their production process, consistency, and other factors. 

The main difference between bubble hash and rosin is that rosin requires heat and pressure to create while bubble hash can be produced using just ice water and gravity.

What Is Bubble Hash?

Bubble hash is a type of hashish created using an ice water extraction process. It’s sometimes referred to as ice hash or ice water hash.

Fresh frozen or dried-and-cured cannabis buds are submerged in a chamber with ice and water. As the water is agitated, the cannabinoid-rich trichomes quickly separate from the plant. The trichomes then pass through a series of bubble hash bags of varying micron sizes (typically between 25μm to 220μm), leaving behind the trim and preserving only the purest resin. The resulting material is then dried (professional manufacturers and extraction techs commonly use a freeze dryer to preserve maximum quality).

Pictured: wet hash being scooped on to a tray prior to freeze drying

If your goal is to achieve a live rosin as your end product, it’s best to use fresh frozen buds. However, you can still get good-quality bubble hash using dried, cured cannabis. 

Bubble Hash vs Dry Sift

Bubble hash is distinct from traditional dry sift hash. With dry sift, the trichomes are typically separated from the cannabis plant using 90μm- to 220μm-micron sifting screens and then compressed using a pollen press. This is the quickest, easiest, and most inexpensive way to make hashish, but it’s also the least precise.

Dry sift is subject to surface contamination and also contains more unwanted plant material. As a result, the cannabinoids and terpenes generally aren’t as highly concentrated and therefore are not as potent. Dry sift also doesn’t melt as fully as bubble hash in most cases. It is possible to produce 6-star full-melt dry sift, but it’s more difficult to make and extremely rare. To achieve affordable full-melt hash with consistent results, bubble hash is still the gold standard.

Bubble hash is also unique for being a “live” product, meaning that the starting plant material is frozen as opposed to being cured or dried. As a result, it offers a unique flavor and effect similar to live resins—but without the solvents.

Full-Melt Bubble Hash – Understanding the Star Rating System 

Bubble hash is rated on a scale of 1 to 6 stars according to how effectively it melts when heated. The more it melts, the fewer impurities that are present. Bubble hash actually gets its name from the tiny bubbles that emerge as the concentrate melts. This concentrate is rated on a 6-star scale: 6 stars is considered full-melt, 3 and 4 stars are considered half-melt, and 1 to 2 stars are considered cooking-grade hash.

Pictured: full melt, 6 star bubble hash made by Essential Extracts (Instagram: @essentialextractsllc)

Most bubble hash is 5 stars which is close to full-melt but not quite there. Still, many manufacturers will market their 5-star hash as “full melt” because it moves the product. While 3-and-4-star hash are good for bowl toppers, some people still consider them cooking grade.

Cooking-grade hash is considered unsuitable for dabbing and vaping due to the high concentration of plant debris, usually in the form of fragmented leaves from the buds. Half-melt is suitable for vaping but burns out much more quickly than full-melt; it can also be uncomfortable on the throat. For anyone seeking to produce premium-quality bubble hash, full-melt is the way to go. And while there are numerous ways to make bubble hash—such as with a hand mixer or a bucket and spatula—the only way to ensure consistent, full-melt quality is with the help of a professional hash-washing system like a Bruteless™ Bubble Hash Washing Vessel.

What Is Rosin? 

Rosin is a highly potent solventless extract; in fact, its name is sometimes used interchangeably with solventless extraction. It has a consistency and function similar to popular extracts like wax and shatter, but the principal distinction is that the cannabinoids and terpenes are extracted without the intervention of a solvent like butane, ethanol, or supercritical carbon dioxide.

Pictured: rosin dripping from the Longs Peak press

Rather, the extraction is completed using only a combination of heat and pressure. The cannabis product—usually dried flower, kief, dry sift, or bubble hash—is firmly pressurized between two heated plates at a temperature of about 120°F to 220°F on average. The resulting extract is collected onto a sheet of parchment paper or into a jar.

How Rosin Is Made

One benefit of rosin is that it can emulate the look and feel of almost any major solvent-based extract. The consistency of rosin can vary based on the temperature at which it’s extracted, the moisture content of the source material, and the curing methods used. For example, while rosin commonly has a viscous or waxy consistency, it can also resemble shatter when extracted at a high temperature.

Are Bubble Hash and Rosin Both Solventless Extracts? 

While both rosin and hash are both the products of solventless extraction, there is some nuance as to the definition of an extract. The word “extract” is traditionally reserved for butane hash oil (BHO) and other solvent-based hash oils, but rosin has assumed the title of “solventless extract” since the heat and pressure isolate the terpenes and cannabinoids much like a solvent—the only difference is that a solventless extract is achieved via mechanical separation and not by means of chemical intervention.

Hashish is traditionally recognized not as an extract but as a concentrate. This, however, is a trivial distinction. Dry sift hash, much like rosin, is commonly the product of mechanical separation, and bubble hash uses agitated ice water to isolate the trichomes in the same manner. Rather than being chemically or physically drawn out of the plant, the active compounds are collected and compressed. So while the use of solvents may represent the traditional dividing line between concentrates and extracts, this distinction is losing its meaning as solventless extractions become more popular and more refined. 

Once processed, a concentrate like bubble hash can be further manipulated into an even more refined solventless extract (rosin) with the help of targeted heat and pressure. This may help to increase the potency of the concentrate, remove additional impurities, alter the texture or consistency, and allow for more complete melting, especially if the hash is only half-melt or cooking grade.

Bubble Hash vs Rosin — Similarities 

Ice water hash and rosin are both partial- to full-melt cannabis extracts created without solvents. Both are commonly used with dabbing and vaping equipment, and both consist of highly concentrated cannabinoids and terpenes.

In terms of THC concentration, bubble hash and rosin are both substantially more potent than dry herb cannabis. The total THC concentration can vary depending on the quality of the extraction and the cannabinoid profile of the original plant material, but in general, both extracts can boast THC concentrations well above 50%. In most cases, rosin will have a higher concentration. Whereas bubble hash may contain up to 60% THC, rosin (especially hash rosin) can measure as high as 90%—similar to solvent-based extracts.

Pictured: bubble hash (L) and first press live rosin (R) made by Eric Simpson (Instagram: @simpsonsolventless)

As solventless extracts, bubble hash and rosin also share one key limitation. Only a fraction of existing strains—about one-third, by some estimates—lend themselves to high-quality, profitable extraction, which means that producers must be mindful of the strains they use to produce hash and rosin. This is due in part to the number of trichomes on the plant but also to the trichome shape and size. If the plant lacks sufficient trichomes, or if the micron size of the trichomes isn’t sufficient for adequate filtration, the yield is going to be low. Producers should always seek out trichome-rich strains with the classic capitate-stalked, or glandular-domed, trichome shape.

Bubble Hash vs Rosin — Differences 

One of the most significant distinctions between ice water hash and rosin is the up-front production cost. A quality rosin press can range between $3,000 and $10,000 in price while a basic home hash washing system can be purchased for as little as $1,600 (larger commercial systems start around $10,000). Processing bubble hash can also be more labor-intensive, while a rosin press is almost fully automated.

Another key distinction is the extraction process itself. Bubble hash is a form of hashish created by detaching and filtering the trichomes. Rosin is a pure cannabis extraction achieved through heat and pressurization. Rosin is commonly more psychotropic due to its higher THC concentration, and it’s more malleable since it can assume different textures and consistencies.

Rosin and hash also have some different uses. Rosin is used as a basis for edibles, topicals, pre-rolls, and other cannabis preparations, while hash is used to make hash joints, infused joints, and hand-pressed hash consumables. Both concentrates are commonly used for dabbing and vaping.

It is also worth noting the distinction between flower rosin and hash rosin. Flower rosin is created from dried flower, whereas hash rosin is created from bubble hash. Flower rosin is popular with home producers because it can be produced more affordably and in fewer steps, and it’s an extremely potent and high-quality product on its own.

Pictured: Girl Scout Cookies flower rosin after the press on the Pikes Peak V2 rosin press

Hash rosin is more refined because the source material has already undergone an extraction process to remove unwanted plant matter. Hash rosin generally maintains a lighter color, a cleaner flavor profile, and higher potency than flower rosin, which is why it is often preferred by commercial producers and extraction technicians.

Bubble Hash vs Rosin — Which Is Superior? 

Bubble hash and rosin are both among the cleanest and highest-quality cannabis concentrates. While neither is superior to the other, each has its own merit. Bubble hash is more cost-effective to produce and offers a less intense psychoactive experience. Rosin is easier to extract in less time and can be made to emulate the effects and consistency of most popular solvent-based extracts. For unparalleled quality and purity, these two extractions can be combined in the form of hash rosin.

Choosing the best extraction system ultimately depends on the needs and goals of the end user. PurePressure offers the most trusted and reliable rosin- and hash-making tools in the cannabis industry, so be sure to explore our full selection of equipment and materials. Then decide yourself which extraction method is right for you.