Hash Rosin 101: Lessons from Experienced Solventless Extractors

Made with no more than water, heat, pressure, and a few tools, hash rosin has become one of the most prized forms of cannabis resin today. Most hash rosin is made by squishing ice water hash instead of flower at the right temperature and pressure levels for yields that fail to rival solvent extractions. It also requires high-quality and properly maintained starting material to match the flavor and melt-quality of something made with hydrocarbon solvents.

There are also varying qualities of hash rosin. But thanks to the taste of concentrate connoisseurs, products like live rosin have become the most expensive and limited cannabis products being sold today. To better understand the many forms of modern hash rosin, I sat down with four premiere solventless extractors from Michigan with varying perspectives during the last High Times event in Detroit.

Solventless Extractors

Today’s hashmakers press their hash into rosin and don the titles of solventless extractors. The extractors I spoke to have several years of experience working with rosin.

After originally outsourcing their plant material to other hashmakers for years, the founder of Superior Flowers, Kerry, started Superior Solventless to create some of the highest-grade single source hash rosin in the state. Seeing jars with his labels in the stashes of most other competing local hashmakers I’ve met speaks volumes to how much his work is respected in the community.

Tyler of Wojo Wax recently took home a second-place medal for Best Non-Solvent Concentrate with their single source Cream D’Mint at the Michigan Cannabis Cup in 2019. Tyler said he has been making hash for about 2 and a half years but feels he really found his groove after taking a hashmaking consult in Las Vegas about a year ago.

Anthony AKA the Organic Mechanic, has been growing and making traditional hash for over 15 years with a focus on pressing rosin over the last two to three years. He’s a hash veteran that I’ve seen doing live demos and pressing hash and flowers that guests bring to his booth at the Cannabis Cup over the last few years.

Mark from Covert Extracts is one of the first to introduce mechanically separated hash rosin to Michigan cannabis consumers. Using the technique, he took first place for Non-Solvent Concentrate with the mechanically separated Mother’s Milk THCA and terpenes grown by Ghostbudsters Farm at the Michigan Cannabis Cup in 2019.

Not All Hash is Made Equal

When it comes to hash rosin, terms like 90u and 120u are different parts of the trichome separated by size. The “u” or μ to be accurate is a measurement that refers to the different micron sizes of the holes in the multiple bags used to filter and separate trichomes from the rest of the plant during the “washing” process.

“Washing” is slang for making ice water hash. More specifically, it is when plant material is put into a bucket of ice water and stirred before it is strained, leaving only hash behind. However, it’s worth noting that dry sift hash can be made without water and ice but most of the live rosin on shelves today is made by turning ice water hash made with freshly frozen materials into rosin.

In fact, all four of the hashmakers I interviewed use ice water hash over dry sift material when making their rosin.

Beyond that, different hashmakers include or exclude certain trichome sizes from their final product. As a result, certain jars of hash and rosin being sold on the market are labeled as 90u, 120u, full spectrum or some range in between.

Differences in Micron Sizes

Kerry of Superior Solventless broke down the differences between the separate micron sizes and what they mean to consumers.

He compared washing flowers to straining pasta. Big holes let the water out and keep all the stuff you want isolated from falling through. However, in the case of making hash, multiple strainers with smaller and smaller holes are needed to separate the different parts of the trichome from the rest of the plant.

“So, when you’re looking at something like 120u [up close], you’re going to see things that are intact. Basically, a stalk and glandular head right up on top. Then, when you see a 90u or a 73u, you’re mainly going to see heads. Heads that have been knocked off the stalks. You can even see them both individually in the 73 and 90u. That generally is what melts really well. Followed down by 45u and 25u.”

The trichome head has proven to be the most prized component of the plant. The fact that they mostly end up in the 90 and 73u bags as Kerry describes is why jars of pure 90 or 73u hash rosin have become more expensive and desired than full spectrum hash by some.

To get a better idea of what goes into the rosin I’ve been smoking, I asked the four hashmakers what sizes they include in their final product and why.

What is Full Spectrum Hash Rosin?

When asked if they leave the 25u or anything else out of their full spectrum rosin, Kerry replied, “We do not. Our motto or our philosophy and principle is to be full spectrum from the beginning to the end of the process.”

According to Kerry, the 90u and 73u are the “meat and potatoes of your dinner plate” and make up the majority of the weight of the yield. In fact, he claimed 90u alone “makes up 70 percent of your wash.”

He warned consumers that if they see a product that’s labeled 90u and you see that same strain from the same company in full spectrum form as well, there’s a chance the 90 or 73u were left out of that full spectrum. That means you’re only getting about 30 percent of the actual hash spectrum despite the full spectrum label.

When asked if he prefers to smoke 90u over full spectrum Kerry said he personally feels 90u lacks certain flavors and the “entourage effect” from missing cannabinoids that would have been in the full spectrum.  

“We have one product. That product is all full spectrum. From there we manipulate the consistency,” he said.

The other three hashmakers I spoke to leave what they perceive as the less desirable ends of the hash spectrum like 25 and the much higher microns out of the final product.

Which Microns Make the Cut?

In response to what goes into their full spectrum, Anthony from the Organic Mechanic responded, “45-159u is what I use for my full spectrum.”

He added that he leaves out the 25 and the 159 because “in my personal opinion, it’s all the broken stalks and little pieces of heads that fall through.”

Anthony also added that you would have to wash an extremely large quantity for the 25u to amount to anything worthwhile.

Tyler of Wojo Wax agreed by saying, “like Anthony said, I catch 40 to 159. I’ve done 25 before and never went above 159u. My reasoning for it is it just makes the color a little bit darker and a lot of people base it [the quality] on color. I didn’t notice much of a difference as far as effect. Yields are obviously a little bit better if you are throwing in those bags, but I’ll sacrifice that yield for the lighter color.”

Covert also found that, in his experience, the 45 to 159u range for his full spectrum rosin was the best for maintaining the flavor of the original plant. The remaining hash that get left out of smokable product is still used in capsules or edibles.

I asked Kerry why he felt less inclined to leave out the 25u and he admitted, “the 70u is going to be white, the 25u or the 159 and above is definitely going to be on the greener, darker, less smelly side.”

But he added that he believes the ends have beneficial properties and those parts make up a much smaller portion of the weight of the wash.

Furthermore, when you make rosin, “you’re taking all the hash and you’re putting it through an entire filtration process again and you can look at that bag and you can see what’s leftover.”

Never Judge a Book by Its Cover

Hashmakers are tasked with selecting strains of flower that will provide a sustainable yield and desirable characteristics after being washed and pressed into rosin.

When asked what his favorite strain to wash was, Kerry of Superior Flowers responded, “I would say Purple Pebbles as well as TKP currently. The TKP was very deceptive when I was running through the pheno hunt. The plant to the naked eyes doesn’t look covered in frost like the Cookies strain.”

Despite the lack of visible frost on the plant, he assured us the yields from washing the TKP were surprisingly high.

And vice versa, he added, “if you’re familiar with the MAC, looking at it you would think ‘wow, that thing is covered [in frost], if it gets washed it’s going to do phenomenal,’ but sometimes that’s not the case and you never want to judge a book by its cover.”

Tyler’s current favorite plant to wash is Sundae Driver because it “checks every single box from nose to taste to yield.”

He described it as a delicious dessert dab with fruity flavors that speak to the Grape Pie half of its lineage.

The Organic Mechanic had similar woes with MAC and Tyler from Wojo Wax agreed that he’s washed material that was frosty in appearance but only yielded .3% — and when you’re getting that little in return, it becomes impossible for hashmakers to keep their lights on. To put that .3% into perspective, yields for hash-friendly strains like GMO can be as high as 8%.

Anthony from the Organic Mechanic said his favorite strain to wash is GG#4 because it has been consistent in every category including yield, potency and smell.

“The color on it is beautiful, the taste, the yield, the terp on it is just loud. Everybody that has got a hold of it likes it. Also, Cherry Punch from Greener Thumb’s outdoor grow is another one of my favorites because of the terps.”

Mark, the lead extractor for Covert Extracts says his current favorite is the mountain cut of Tropicanna Cookies bred by Harry Palms and grown by Ghostbudsters Farm because of the prominent terpene profile. He gave GMO an honorable mention as well because “it dumps, it’s stinky and it checks every box for me. It’s my go-to.”

Mason Jar Test Wash

Tyler admits he made the mistake of judging how well a strain would wash based of the quality of its appearance. After putting in tons of work processing an extremely large bulk of flower for a friend that ended up looking far better than it yielded, he learned his lesson the hard way.

Since it is impossible to rely on looks alone to tell how well a strain will wash after the harvest, Tyler recommends paying attention to genetics and performing a small mason jar test before washing an entire grow and being surprised it didn’t yield enough to break even.

Tyler said that when sourcing starting material, solventless extractors “have to truly look for what strains are going to wash well. You gotta look at the parents and then as you’re growing them too, you can tell by the size of the head if you’re scoping it. A new thing that we started doing is doing a test wash. You can put a small amount of flower in a mason jar with water and ice then start swishing it around to see if those heads fall off because it can be the frostiest plant ever like the MAC and not dump at all. It’s got to want to let that head go because we’re not after the stalk.”

With the mason jar test wash method, Tyler says only about a half ounce of flower is needed rather than using a whole plant or more when it might not yield much.

Live Rosin vs. Cured

Most modern hashmakers exclusively work with “live” or freshly frozen starting material. This is best illustrated by the fact that only one of the four hashmakers I interviewed for this article currently processes dry or cured flower.

I asked Anthony from Organic Mechanic if he preferred using fresh frozen starting material over cured and he replied, “I would do either one if the product was taken care of.”

However, he finds flavor can be lost during the curing process.

On the other hand, the other three hashmakers exclusively work with live products for a number of reasons.

Kerry said in his experience at Superior Solventless, he observed differences in the yield, color, potency and consumer demand.

Tyler used both live and cured products before the Wojo Wax team deciding to only use freshly frozen flowers. Tyler says that in his experience, the yield was higher with cured material. Despite this, he exclusively runs live material because of the enhanced flavor and the fact that it melts better in his experience.

Mark prefers live because it “tastes better, the color is obviously better” and that’s been enough to keep him exclusively working with freshly frozen flowers.

Single Source vs. Outsourcing Flower for Hash Rosin

I asked a few of the hashmakers if they noticed any differences when extracting flower they grew themselves versus outsourcing plant material.

“This is probably my favorite question so far because this to me is where you really get your difference [in hash quality]. We do everything single source,” said Tyler of Wojo Wax.

He says the reason for this is, “growing for hash is different than growing for flower.”

Growing for Hash

“For starters, I’m not defoliating as much as I am for hash because I’m trying to get as much surface area as much as I can. On top of that, I crank my room down as cold I can possibly get it for the last three weeks because that preserves the terpenes which is what we’re ultimately after. Another reason is because I’ve taken [other] people’s materials and it doesn’t always yield well. I don’t want to be the bearer of bad news to somebody that they’re getting .3% back on a wash.”

When asked if he also noticed a difference when washing the same strain from his own grow compared to somebody else’s, Kerry of Superior Solventless admits the experiences were not the same.

“For example, we washed Wedding Cake that we grew and got 5%. We washed someone else’s and got 3%.”

Mechanical Separation vs. Jar Tech

There are two additional ways for hashmakers to further process hash after it has been turned into rosin. Using these techniques, they can turn the consistency of their rosin into something closer to a live resin sauce.

Rosin Jam

One is called “jar tech” which just about anyone should be able to do at home with a jar of fresh-pressed rosin, a source of heat, time and practice. The consistency it creates has been called jam or “caviar” by Superior Solventless and it contains small crystals with a more liquidy high-terpene layer. The layers combine to create an applesauce-like consistency that is less likely to change at room temperature than fresh-pressed rosin.

Unlike the washing and pressing phases, the hashmakers I spoke to claim little to no weight is lost after a jar of hash rosin undergoes the “jar tech.”

On the other hand, the other technique which involves mechanically separating THCA out of the oil comes with a more significant yield loss.

If you come across a jar of solventless rosin with large THCA crystals and oil in it, they were most likely mechanically separated with a press and filters. Then, the crystals are melted down and manipulated into a shape of choice. Usually, they are made to mimic the appearance of popular live resin extracts made with hydrocarbon solvents.

Mechanical Separation

According to Mark of Covert Extracts to make mechanically separated THCA, “you need wax rosin in order to make mechanically separated THCA.”

From there, he says, “to separate the THCA from terpenes I usually press the rosin wax in a 25u press bag at about 135 degrees to start. With a very low pressure at first before building to almost max pressure. Then, I repeat at different temps until I feel enough terpenes are separated. From there you can take the THCA and melt it down into a glass-like consistency at around 240 to 250 degrees.”

Comparing it to the jam tech or fresh press, Mark said it is a “long process and you have about a 25% loss in yield but potency and appearance of the final product sets it apart.”

The process appears to further isolate THCA in hash rosin with Mark claiming to have “had some testing out at 92% THCA.”

There was a point in time when most hash looked the same. It was a dark brown or green in color, grainy and stretchy. That same hash commonly came in a brick, ball, or bullet that may have traveled inside someone’s ass before getting to you.

Fortunately, today’s hash is far more refined and versatile. Made in the under the right condition, it looks lighter in color and can take on the form of dry sift, ice wax, rosin, live rosin, jam, or mechanically separated hash rosin. Not to mention the various consistencies that rosin can be shape-shifted into, like cake batter, sugar, or applesauce.