90µ vs 120µ Hash: What’s the Difference?
The micron number on a hash label tells you which filter bag the resin was collected from during ice-water extraction. It is a measurement of the mesh size that let that particular fraction through, and nothing more. It does not tell you how potent the hash is, how well it melts, or whether it is worth buying. It tells you what size of particle was gathered, and from there you can make some informed guesses about texture, purity and character, but they remain guesses until you actually see and smell the resin.
The reason 90µ and 120µ come up so often is that both sit in the sweet spot of mature trichome head sizes, and both produce some of the most desirable hash in a typical run. Choosing between them is one of the most common decisions a buyer faces, and also one of the most commonly misunderstood.
What Microns Actually Measure
A micron is one thousandth of a millimetre. Ice-water hash is made by washing cannabis in cold water and passing the mixture through a series of filter bags arranged from largest mesh to smallest. Each bag catches a different fraction of what falls through.
The largest bags, 220µ and above, are working bags that catch plant material and let everything else pass. Below that, the extraction bags in the 160µ to 25µ range collect progressively finer material. A bag labelled 90µ has holes roughly 90 microns across; a 120µ bag has holes roughly 120 microns across.
Mature, fully developed trichome heads on most cannabis cultivars fall roughly between 50 and 120 microns in diameter. This means the 90µ and 120µ bags are both capturing particles right in the zone where intact resin heads concentrate, which is why these two fractions are so often the star performers of a wash.
What Lands In Each Fraction
A 120µ bag collects everything that passes through the 160µ bag above it but is too large to pass through the 90µ bag below. So the 120µ fraction contains resin heads roughly 90 to 120 microns in diameter, the largest mature heads, plus some slightly larger particles that may include a small amount of stalk material or partially intact heads.
A 90µ bag collects everything that passes through the 120µ bag but is too large to pass through the 73µ bag below it. So the 90µ fraction contains resin heads roughly 73 to 90 microns in diameter, medium-sized mature heads that are generally very clean, because they are small enough to have shed most stalk and leaf matter by the time they reach this bag.
This is why 90µ hash is often slightly paler and slightly cleaner than 120µ hash. It has been through an additional filtration stage, so fewer contaminants made the cut. The 120µ fraction, by contrast, captures the largest resin heads, which tend to carry the heaviest concentration of cannabinoids and the broadest terpene range, but it also carries marginally more non-resin material along with them.
Aroma And Flavour Differences
In practice, the differences between the two fractions are real but modest, and they overlap considerably because both are capturing good, mature resin.
The 120µ fraction tends to be the more expressive of the two on the nose. It captures the largest trichome heads, which hold the biggest volumes of resin and therefore the densest concentration of terpenes. Aromatically it is often louder, broader and more full-spectrum, you get the top notes, the mid-palate and the bass line together. Some people describe it as rounder or more complete.
The 90µ fraction tends to be slightly more focused and refined. It has been filtered one stage further, so the profile is a bit tighter, the top notes are clear and specific, the mid-palate is clean, and the finish is precise rather than broad. Some people find it more elegant; others find it slightly less exciting than the 120µ.
Neither is universally better. If the starting material is excellent and the wash is well executed, both fractions will be outstanding and the differences become matters of preference. If the starting material is mediocre, both fractions will show it, and the gap between them narrows because there is less quality to separate.
Texture And Melt
The 90µ fraction typically melts slightly cleaner because it carries fewer contaminants. On a low-temperature dab it bubbles, domes and liquefies with very little residue, and it is often the fraction most likely to approach a true six-star full melt.
The 120µ fraction melts well too, but may leave a faint trace of ash because of the small amount of non-resin material it carries. In practice, the difference in melt between a 90µ and a 120µ from the same wash is usually visible but minor, a little more residue in the 120µ, a slightly cleaner plate with the 90µ.
Texture is broadly similar. Both arrive soft and pliable when properly made. The 90µ can be slightly sandier and looser; the 120µ can be slightly doughier because the larger heads bind together a touch more readily. Both crumble at room temperature. The differences are subtle enough that most people cannot reliably tell them apart by texture alone.
Colour
Neither fraction has a monopoly on looking good. The 90µ is often marginally paler because it is cleaner, running from off-white through pale blond to light gold. The 120µ can be a shade darker, gold through to light amber, because it includes the larger heads that carry more oxidised resin and a trace more plant material.
Colour is not a reliable quality indicator for either fraction. A poorly made 90µ will be pale and lifeless. A well-made 120µ will be golden and vivid. Judge by aroma and melt, not by how blond the resin happens to be.
Potency
The 120µ fraction often tests marginally higher for total cannabinoids because the largest trichome heads hold the greatest volume of resin. The 90µ fraction can test slightly lower in raw potency but slightly higher in the ratio of desirable compounds to plant matter.
In practice, the potency difference between 90µ and 120µ hash from the same wash is usually small enough that it would not be noticeable in consumption. Both are substantially stronger than flower, and both will overwhelm an inexperienced user if dosed carelessly. The difference is real in the lab and largely academic on the dab rig.
Dab Temperature
Both fractions are best dabbed at roughly the same range, cold start at 180 to 200°C for soft ice-water hash. There is no meaningful reason to treat them differently on temperature. What matters far more than the micron number is how the hash was made and stored: a poorly kept 90µ will need more heat to melt than a well-kept 120µ.
Which Should You Buy
There is no universally correct answer, and anyone who tells you one fraction is always better is selling you a simplification.
If you prioritise the cleanest possible melt, the palest colour and the most refined, focused flavour profile, the 90µ is the slightly safer bet. It is the fraction that tends to look and perform best under close inspection, and it is what most competition judges reach for first.
If you prioritise the loudest, broadest and most full-spectrum expression of the cultivar, and you are willing to accept a marginal trade-off in melt cleanliness for a more complete aromatic picture, the 120µ is often the more rewarding fraction. It captures the biggest resin heads at their most expressive.
If you are new to ice-water hash and unsure, buy the one that smells better. The nose knows more than the micron number does.
A practical note: many sellers offer the two fractions as a mixed bag or simply sell their best melt grade without specifying the micron, because the differences are small enough that for most consumers they do not justify separate listing. There is nothing wrong with this. The micron number is most useful when you are choosing between two listings from the same producer and the same wash, where the only variable is the fraction.
When The Micron Number Does Not Matter
A good 120µ from an excellent wash beats a mediocre 90µ from a careless one every time. The micron describes what was collected, not how well it was collected. Starting material, wash technique, drying method and storage all matter more than the filter bag the resin happened to land in.
A maker who fresh-froze the material, ran a cold and gentle wash, dried patiently at low temperature and stored the resin properly will produce outstanding hash at either micron. A maker who used warm water, rushed the dry, or left the resin in a warm room will produce mediocre hash at either micron. The number on the bag is the last variable, not the first.
The same principle applies to price. A 90µ that costs significantly more than a 120µ from the same wash is charging you for the label. If the 120µ smells and melts better, buy it instead and keep the difference.
The Honest Summary
90µ and 120µ are both premium fractions from the heart of the trichome size range. The 90µ is typically slightly cleaner, paler and more refined. The 120µ is typically slightly louder, broader and more expressive. The differences between them are modest and overlap considerably, and both are capable of producing hash at the very top end of what the method can achieve.
Choose by aroma and melt, not by number. The fraction is a useful piece of information, but it was never meant to be the whole story.
Frequently Asked Questions: 90µ vs 120µ Hash
What does the µ symbol mean on hash labels?
It stands for micron, one thousandth of a millimetre. The number refers to the mesh size of the filter bag the resin was collected through during ice-water extraction. A 90µ bag has holes roughly 90 microns across; a 120µ bag has holes roughly 120 microns across.
Is 90µ hash always better than 120µ?
No. The 90µ fraction is typically slightly cleaner and paler because it has been through an additional filtration stage, but the 120µ captures the largest trichome heads and often carries the broadest, loudest terpene profile. Neither is universally superior. It depends on the wash, the material and what you value.
Why does 90µ hash usually cost more?
Because it yields less. In a typical wash, the 90µ fraction is smaller than the 120µ fraction, so there is less of it to sell. Scarcity drives price, not inherent quality. If the 120µ from the same wash smells and melts better, it is the better buy regardless of the micron number.
Does 120µ hash melt as well as 90µ?
Almost, but usually not quite. The 120µ carries marginally more non-resin material because it has not been through the finer 90µ filter, so it may leave a faint trace of light ash. The 90µ generally melts cleaner. In practice the difference is visible but modest, and a well-made 120µ will out-melt a poorly made 90µ every time.
Which fraction is stronger?
The 120µ often tests slightly higher in total cannabinoids because the largest resin heads hold the most volume, but the difference is small enough that most people would not notice it in consumption. Both fractions are considerably stronger than flower, and both should be approached with the same caution on dosing.
Which smells better?
The 120µ tends to be broader and more full-spectrum on the nose, louder, rounder, more complete. The 90µ tends to be more focused, refined and precise. If you want the widest aromatic expression of the cultivar, lean toward the 120µ. If you want the cleanest and most elegant read, lean toward the 90µ.
Can I tell the difference by looking at them?
Sometimes, but not reliably. The 90µ is often marginally paler and sandier in texture. The 120µ is often a shade darker and slightly doughier. These are tendencies, not rules, a dark 90µ and a pale 120µ from different washes would be indistinguishable by sight alone.
Do I dab them at different temperatures?
No. Both are best cold-started at roughly 180–200°C. The micron fraction does not dictate temperature. What matters is that both are soft ice-water resins with volatile terpenes, and both reward restraint on heat.
What about 73µ and other fractions?
The 73µ sits just below the 90µ and is another premium fraction, often even cleaner and paler but with a smaller yield. Fractions below 70µ tend to include more immature heads and fine debris; fractions above 130µ carry progressively more plant material. The 73–120µ range is the heartland where the best resin concentrates.
If a seller does not specify the micron, should I be suspicious?
Not necessarily. Many producers sell their best melt grade without breaking it down by fraction, because the differences are small enough that most consumers do not need the distinction. The micron number is most useful when choosing between two listings from the same producer and the same wash. If the hash smells vivid and melts cleanly, the fraction it came from matters less than the quality of the work.
Is the micron system the same for dry sift?
No. Dry sift is graded by screen mesh too, but the particle size distributions differ because there is no water to separate heads from stalks. A 90µ ice-water fraction and a 90µ dry sift fraction are not directly comparable. The system only means something within the same extraction method.
So which one should I actually buy?
Whichever smells better. The micron number is useful context, but aroma and melt are the real quality indicators. If you can inspect both, pick the one that speaks to you. If you cannot, go with the producer you trust rather than the fraction you assume is better.
