Rosin: the pure extract of hashish, leaving all of the capitate stalks and waxy resin heads behind, presenting only the terpenes, esters, flavonoids and cannabinoids intact.

Back in 2013, there was a person that picked-up cannabis, and cannabis extract samples to be tested by a fairly large testing laboratory, here in Southern California, as we have been making dosed-cannabis medications for doctors for many years, and he was telling me about something they were playing around with in the lab, a press, that could literally squeeze the pure essence out of cannabis, and trichomes, and they were calling it “ROSIN”.

That person went on to start one of the largest rosin press companies in the cannabis market today (I won’t name names), but suffice it to say, hindsight is always 20/20.

This is where we will explore rosin, and the making of rosin, from hash or pressed flower.

We’ll start with pressing cannabis flower, as that is the starting point with all of this, and it's very easy to do.

Let me begin by saying, the actual art of pressing rosin from cannabis flower must be learned by trial and error, and what I’m going to go through is an overview of how that is accomplished.

With regard to actually pressing your material, this will give you a head-start, so that if you are considering entering into the world of rosin, when you purchase your press, to begin this journey, you will be prepared.

All you need is a hair straightener, a “C- clamp”, and some parchment paper to start, although, within a few hours, days, or weeks at the most, you’ll be ready to purchase a rosin “press”, as you’ll be amazed at the differences between rosin and all other forms of concentrates.

The fact is, you don’t need a 10-ton press to create quality rosin -- pressing cannabis flower takes between 600 and 1000 pounds of pressure to yield beautiful rosin.

Pressing hash requires less pressure, as you have isolated the trichomes only, and it requires only 300 to 800 PSI to press out the contents of your trichomes.

Cannabis flowers are covered in trichomes, which we learned to wash off in the last part of this series, but the flowers can also be pressed without washing to reclaim the “goodness”.

The next thing you’ll need is what is referred to as a “pollen press”, traditionally used to press hash into “pucks”, but very useful to press flower into pucks for pressing for rosin.

What this does is compact the flower into a very small, round “puck” (named after a hockey puck, which it resembles, just much smaller).

You can press 3.5 - 7 grams of buds/flower into pucks very easily with this tool, and they are available for purchase online very inexpensively. This is an indispensable tool for producing high-quality rosin from cannabis flower.

Of course, the old computer acronym of “GIGO”, or “Garbage In, Garbage Out” applies very well to this. The more trichome-laden the flowers, the better quality, and quantity of rosin you will yield, as always, quality is key. However, when pressing cannabis flower, there are aspects beyond quality that need some consideration. Primarily, freshness and moisture content of your bud will affect your rosin the most.

Fully dried bud isn’t the best starting material for making flower rosin. Fresh uncured cannabis that has been frozen almost immediately after harvesting is the most desirable candidate, thanks to its higher cannabinoid and terpene content. The moisture in fresh buds also acts as a buffer to help release more oils, instead of them being sucked up like a sponge by the dry plant material of cured bud.

The key here is monitoring and knowing the relative humidity of the flower intended for use.This is very important, because if your buds are too dry, the oil that is being pressed out, will be absorbed by the dry plant material.We need the flower to be high in moisture content (with a relative humidity of at least 55%, and even more optimally, around 65%.This keeps the flower moist and helps expel the oil to the outer edges when pressed, separating it from the plant material.

Of all the different variables of rosin making, correct pressing times and temperatures are the most important for the best results.

It’s also the area that is open to experimentation and debate. Reaching the perfect settings can be challenging, and is an art to perfect, so whether you go low and slow or high and fast a good understanding of how these two parameters affect quality and yield is important to produce the best rosin you can.

Temperatures can range from as low as 135-165 degrees Fahrenheit/57 to 74 degrees Celsius, to 220 degrees Fahrenheit/105 degrees Celsius, but I wouldn’t recommend much higher, as you will be destroying terpenes and other volatile compounds at higher temperatures

Generally, lower temperatures are better, as they don’t decarboxylate the end product, and retain a far wider range of terpenes, which begin to evaporate immediately upon pressing (making the lab/workshop/house smell delicious!).

The pressure spectrum for rosin sits roughly between 300 and 1000psi. Flower requires more pressure, closer to the upper range of 600 to 1000psi, whereas dry-sift or bubble hash only requires lower pressure, at 300 to 800psi.

Ultimately what pressure to use will vary from press to press. Differing pressures will also be determining factors for time and temperature settings, so it’s important to experiment with the three variables if you want to keep improving the quality of your rosin.

The cannabis flower puck is placed into a mesh bag before pressing, to contain the plant material as it is being pressed.

Generally, for flower, I use 90-micron mesh bags; for hash, I use 25-micron mesh.

Filtering also has a big impact on rosin quality and yields.

Generally, the smaller the micron rating of your bag, the higher the quality of rosin produced, but at the expense of yield. This is because finer micron values only allow resin packed trichome heads to pass through them, leaving behind larger, lower grade particles.You can either try to strike a balance between potency and yield with a larger micron rating, or you can specifically target the premium trichomes with a super fine mesh. However, there’s always going to be a trade-off between the two.