Hi THCFarmer Forum fam,
My name is Nancy and I'm part of the customer happiness team at The Press Club, a small family owned premium solventless company located in sunny California!
What is solventless you might ask? Well, that's why I'm here!
THCFarmer Cannabis Cultivation Network has officially partnered with The Press Club to bring you the latest in solventless to the amazing cannabis growing community here! We're here to educate and answer all questions (and hopefully inspire some growers to be rosin pressers too)!
Solventless is a cannabis concentrate that's created without using any chemicals or solvents. Using only heat from aluminum plates and pressure from an industrial press, you can instantly transform your trichomes into different forms of concentrates. Similar to wine-making when grapes are squeezed for their juice, trichomes are squeezed for their active cannabinoids and terpenes during rosin pressing. The final result is called rosin, a solventless concentrate that can be further refined or transformed into different forms and consistencies - from budder to THCA to shatter to everything in between.
After being introduced to rosin pressing in 2014, the founders at The Press Club fell in love with the solventless extraction process. One thing they didn't like was how expensive filter bags - also known as rosin bags - were for rosin pressing. Not only were they expensive, they weren't dependable - often tearing and ripping under pressure.
After 8,610 hours of research (we counted), 16 trips to nylon factories, 2 years of lab testing, 0 blowouts and 1 proprietary stitch, The Press Club was born.
Now The Press Club's mission is focused on pushing the cannabis industry forward, educating people about this wonderful plant and becoming a one-stop-shop for all premium solventless products from washing to rosin bags and accessories. All our filters are made with our proprietary pink stitching, making our bags 5x stronger than competitors, and all bags come with our Zero Blowout Guarantee™. We also donate 5% of every purchase to support American veterans and NORML.
In this "From Soil To Oil: How To Cultivate, Prep, and Process Cannabis for Solventless Extraction" guide we created specifically for THCFarmer Forums, Concentrates & Processing, we take you from seed to oil - explaining every aspect of the rosin pressing process from picking plant genetics to explaining what equipment is required to start your solventless journey.
Feel free to email the team at [email protected] if you have any questions! We're always here to help!
We also partnered with THCFarmer Cannabis Cultivation Network to give everyone here 10%-off any purchase with us (use code: THCFARMER at checkout).
INTRODUCTION: ROSIN 101
The best solventless extractions require the best cannabis for starting material. Whether it’s bubble hash, dry sift, or rosin, premium cannabis concentrates are derived from cannabis flowers of superior genetics grown in the ideal environment, and harvested at peak ripeness. The process of creating cannabis concentrates with solventless extraction methods (without the use of solvents like butane or CO2) amplifies the existing quality of the cannabis from which it’s derived. Solventless extraction isn’t magic, and it won’t transform mediocre cannabis into a remarkable concentrate. The starting material directly determines the end product. Therefore, cultivating, harvesting, and preparing exceptional cannabis is key to making exceptional solventless extractions.
The two main categories of solventless cannabis extractions are rosin and hash. The two forms of hash include bubble hash and dry sift hash, both of which are composed mostly of trichome heads with very little plant material. Bubble hash is created using the ice water extraction method, while dry sift is created by sweeping dry cannabis material over a series of mesh screens.
Rosin can be made using flower, bubble, or dry sift as starting material, and the resulting rosin is known as either flower rosin, bubble hash rosin (or simply hash rosin), or sift rosin. Flower rosin is the fastest and most straightforward concentrate to produce, while hash rosin is generally considered the highest quality.
Making rosin begins with loading cannabis starting material inside nylon filter bags, pre-pressing it with an aluminum mold, enclosing it within a folded piece of parchment paper, and placing it between rosin press plates where heat and pressure can be applied (1). The press (2) gives us the right amount of pressure needed to extract rosin, while the heated plates provide high temperatures needed to liquefy the cannabis trichomes that contain all of the therapeutic compounds we’re aiming to extract. Several types of presses and rosin press plates are used in a variety of configurations, from hydraulic to pneumatic presses (8) with either caged or uncaged plate (9) set ups. Even a hair straightener will work for pressing rosin (3)! We’ll outline the specific heat (4) and pressure (5) settings applied to each type of starting material in this overview.
Pre-press molds (6) are often used to compress the starting material inside the rosin filter bags before extraction. The loaded rosin bags (7) are placed inside a folded sheet of parchment paper, which catches and holds the rosin as it’s extracted between the heated press plates. The rosin is then collected from the parchment paper with a rosin stamp or dab tool.
(1) What Equipment You Need To Press Rosin
(2) How To Build Your Own Rosin Press
(3) Can You Really Press Rosin with a Hair Straightener?
(4) Rosin Press Temperature Guide
(5) Rosin Press Pressure Guide
(6) 3 Reasons Why You Need a Pre Press Mold
(7) How To Pack Rosin Bags
(8) Hydraulic vs Pneumatic Presses
(9) Caged vs Uncaged Rosin Press Plates
The quality of cannabis starting material is the predominant influencer of the quality of solventless extract it will produce. Just as the quality of cannabis starting material determines the quality of solventless extractions, genetics play a critical role in the outcome of a cannabis grow (10). While there are other impactful variables such as garden environment, plant genetics are the foundation of a high quality harvest. Selecting genetics known for producing copious amounts of resin is a good starting point (11). Specifically, flowers with an abundance of capitate stalked trichomes are what we’re aiming to cultivate, and some cultivars (strains/genetics) tend to produce more than others. Choosing seeds or clones that contain these genetics is the first decision to make when planning your operation (12).
(10) Best Cannabis Strains for Pressing Rosin
(11) Which Cannabis Strains Are Best for Washing Bubble Hash?
(12) Why Is Pheno-Hunting Important for Rosin?
The right genetics can only express their most spectacular traits if given an optimum environment in which to flourish. Whether it’s an indoor or outdoor grow space, factors like light, temperature, humidity, and nutrients will determine the outcome of the harvest. The best genetics placed in a subpar growing environment will never live up to their potential. Thoughtful design and configuration, intentional selection of equipment, and meticulous attention to detail are components of a quality garden (13). At the same time, nature knows what’s best (14). We are facilitating growth, not playing God. The idea is to create the best space for the cannabis plant to do its thing (15).
(13) Cultivating Soil for Maximum Terpene Expression
(14) Guide To Pressing Rosin for the Outdoor Grower
(15) Do I Need To Grow My Own Cannabis To Press Rosin?
HARVEST AT PEAK RIPENESS
Good genetics placed in the ideal growing environment will produce resin-packed buds at harvest time. But how can you determine the best time to harvest your flowers? The answer lies in the trichomes (16). Those tiny translucent globes convey peak levels of ripeness based on their coloration, starting first as completely clear, then moving to milky and finally amber-colored (17). When the trichome heads are predominantly amber, this signals the peak of resin production and the height of therapeutic compounds within. Using a magnifier like a jeweler’s loupe is the best way to peer into the world of trichomes and gage maximum ripeness.
(16) Guide To Trichomes and Solventless Extraction
(17) How To Harvest Cannabis at Peak Trichome Ripeness
FLOWER ROSIN, SIFT ROSIN, OR BUBBLE HASH ROSIN?
Before harvest day it’s important to decide how you intend to use the flowers. Assuming that solventless extraction (18) is the goal, you have a few different options. Flower rosin can be produced using air dried flowers and requires less processing than dry sift or bubble hash rosin. If flower rosin is the aim, you simply need to harvest and dry the flowers, then press them using heated rosin press plates.
Flower rosin is a great option if you’re just getting started in rosin and want to learn the mechanics and general workflow, without having to first process the flowers into hash (19).
If hash rosin is your objective, the harvested flowers need to be processed into hash, which is either dry sift or bubble (bubble hash being the more pure of the two types of hash). Dry sift hash is made by sweeping dried, trichome-rich cannabis material over a set of mesh sieving screens, employing the force of gravity to separate trichomes from the rest of the material. Bubble hash involves a bit more complexity than dry sift, and is made using a process called ice water extraction. Ice water extraction uses cold water and a liquid vortex to separate trichomes from the remaining plant material.
Both flower rosin and dry sift rosin require dried cannabis flowers as starting material, so hanging cannabis to dry immediately after harvest is the way to go. Although dry sift hash needs to be made with dry cannabis material, bubble hash can be made with either dry or “fresh frozen” cannabis. Fresh frozen cannabis refers to material that’s been frozen immediately after harvest to preserve the best qualities of the living plant, such as terpene content. Fresh frozen material is only used in the production of bubble hash and bubble hash rosin.
Rosin filter bags hold the cannabis starting material and provide filtration while heat and pressure are applied in between the rosin press plates. As the rosin is squeezed from the material it passes through the filter bags before oozing out onto the parchment paper. Unwanted material is contained within the rosin bags, while pure rosin flows through (20).
(18) Top 3 Reasons Why Solventless Is Superior
(19) Flower Rosin vs Hash Rosin
(20) Average Rosin Yields from Various Cannabis Starting Material
Drying Flowers for Flower Rosin
If pressing flower rosin is your objective, drying your freshly-harvested crop is the first step (21). Wet cannabis can’t be pressed into rosin, so hanging the flowers upside down to dry anywhere from several days up to two weeks will bring the material to the proper moisture level. In preparation for rosin production, cannabis flowers should maintain 60-65% relative humidity (RH). The best way to monitor moisture levels is with a digital hygrometer and a glass mason jar. Place the buds and a digital hygrometer within a sealed mason jar, and wait until the reading stabilizes. If the buds are showing RH over 65% then keep drying. If under 60%, you can rehydrate the material in preparation for rosin production (22).
(21) What Is the Best Environment for Hang Drying Cannabis Flowers?
(22) How To Rehydrate Cannabis Flowers That Are Too Dry for Pressing Rosin
Pressing Flower Rosin
Once the buds have achieved optimum moisture content, it’s time to prep them for rosin production (23). Selecting the correct rosin filter bags and setting the correct temperature and pressure outputs at your rosin press plates are the leading variables of the process (24). 90-120 micron rosin filter bags provide the ideal filtration power for pressing flower rosin (25). Whole buds should be broken up into smaller, popcorn-sized pieces by hand, not ground into a powder with a grinder. Regardless of the starting material you’re using, the rosin filter bag should be packed tightly to avoid empty spaces and large gaps within the material.
180-210 degrees Fahrenheit at 650-1000 PSI is the recommended range for pressing flower rosin (26). Note that pressure readings on your rosin press may not be the amount of pressure that’s actually being applied to your starting material at the bag. Calculating Platen PSI for your specific set up will help ensure accuracy (27).
(23) How To Find the Best Flower for Pressing Rosin
(24) What Micron Do I Use?
(25) How To Press Flower Rosin Starter Guide
(26) Top 5 Rosin Pressing Tips for Flower
(27) How To Calculate Platen PSI
DRY SIFT ROSIN
Making Dry Sift Hash
Dry sift is a form of solventless cannabis concentrate that involves separating trichome heads from cannabis plant material and isolating them for collection using a set of mesh sieving screens (28). Resin-coated cannabis flower or trim leaf is whisked back and forth over a series of stackable screens composed of varying pore sizes. While plant material is contained on the upper screens, trichome heads are small enough to pass through for collection on the lower screens (29). Dry sift can be made using a steady, sweeping motion of your hands across the surface area of the screens, or with the help of a card (e.g. a credit card) to move and gently agitate the cannabis over the mesh filter. This technique is known as “carding”.
(28) What Is Dry Sift?
(29) The Ultimate Guide To Dry Sift
Cleaning Dry Sift Hash with Static Tech
Trichome heads that collect on top of sifting screens are often intermingled with a noticeable amount of tiny plant particles that also made their way through the mesh filter. The most desirable hash contains trichome heads exclusively, without the presence of other plant material. It’s difficult to remove plant material from dry sift hash, but it can be done with a technique known as Static Tech. There are various forms of static tech, but the basic principle involves the use of static electricity to separate trichomes from plant material in such a way that the trichomes can be collected and the remaining material can be discarded.
Pressing Sift Rosin
While dry sift can be consumed on its own, most extractors prefer to press dry sift into rosin. Hash rosin that’s been pressed from dry sift is called sift rosin, and it’s generally considered a step up in quality from flower rosin.
As with pressing flower rosin, selecting the correct micron rosin filter bag plus temperature and pressure settings at the rosin press are the top variables to consider. Smaller micron rosin filter bags can accommodate dry sift, so 37-75 micron bags are generally suited for pressing sift, depending on the purity. In general, the more pure the source material you’re pressing, the smaller the micron size rosin bag you need. Double-bagging is also a good idea with pressing both sift and bubble hash rosin. The volume of rosin outflow from the sift and bubble hash is generally higher than that from flower rosin, and the additional reinforcement of a second bag helps to prevent blowouts. A larger micron such as 120 or 160 is often used as the outer bag, but the recommended 37-75 microns for sift will also work doubled-up. If using different microns, the larger micron should be on the outside.
140-200 degrees Fahrenheit with Platen PSI between 500-1500 are good ranges in which to experiment with sift rosin.
BUBBLE HASH ROSIN
Washing Bubble Hash
Bubble hash is the highest quality of hash, known as bubble hash because of the small bubbles that appear on the surface when exposed to heat (30). Bubble hash is rated on a scale of one to six stars, 6-star hash being the most pure and highest-quality. 5 and 6-star hash is also known as full melt hash, because it will fully burn away and leave no waxes or residuals behind on a nail or bowl when smoked.
Making bubble hash is often referred to as “washing” hash, and involves a process known as Ice Water Extraction (31). Cannabis material (either flowers or trichome-covered trim leaves) is mixed in a bucket with ice water, stirred together with a circular motion to create a vortex in the water. This vortex, coupled with the ice cold temperature of the water, allows the trichome heads to break away from their stalks (32). This slurry of ice water, plant material, and trichomes is then poured through a series of filter bags, also called Bubble Wash Bags, through which the trichomes heads are separated from the remaining material. While tap water is probably the most convenient water to obtain, it’s not the best. Use RO water when washing hash for the best results (33).
Each wash bag in the series contains a different size of filter screen, ranging in pore size from 220 to 25 microns (34). The filters which most closely match the size of full trichome heads will collect the highest grades of hash. Filters larger than trichomes catch and hold plant material that can be removed from the batch, while filters smaller than trichomes catch lesser-qualities of hash containing trichome stalks, broken heads, and tiny pieces of plant material.
After the ice hash water slurry is poured through the filters, the wash bags are removed from the work bucket one by one and gently scraped with a cold metal spoon for the hash that’s collected on the screen. 120, 90, 75, and 50 micron wash bags usually collect the purest hash, composed almost exclusively of trichome heads with minimal contamination (35).
(30) The History of Bubble Hash
(31) How To Wash Bubble Hash
(32) Top 20 Best Tips for Washing Bubble Hash
(33) Why Is RO Water Best for Washing Bubble Hash?
(34) What Is the Purpose of Using Multiple Bubble Wash Bags?
(35) Best Qualities for Bubble Wash Bags
Drying Bubble Hash
Drying the hash that’s collected from the wash bags is a critical step that can make or break the entire process (36). Wet hash invites microbial growth like mold, which will completely ruin the product, rendering it unusable. As the wet hash is scraped from the filter screens, the trichome heads stick together in an amorphous glob, somewhat resembling a loose and extremely wet pancake batter. This patty of hash can be dried using various methods, the most effective of which is freeze drying.
Freeze drying utilizes the process of sublimation coupled with a vacuum chamber to quickly and thoroughly dry the hash with minimal exposure to oxygen (37). Freeze dryers are advanced pieces of equipment that are often used by commercial processors. The cost of freeze dryers can be prohibitive to in-home extractors and casual hobbyists. It just depends on your budget!
Air drying hash is a fine alternative to freeze drying. To air dry hash, immediately freeze the wet hash patty for 24 hours, or until it’s frozen into a solid block. Then take the frozen blob of hash and rub it back and forth across a kitchen sieve or strainer, which breaks the hash into smaller pieces. The resulting is a coarse powder or sand-like consistency in the hash, allowing it to dry out evenly. Without breaking the hash down into smaller pieces like this, moisture will get stuck inside the middle of the hash patty and harbor microbial growth.
Sieve the wet hash over a piece of cardboard lined with parchment paper, and allow it to air dry in a cool, dry, dark space, or inside a refrigerator, until it’s completely dry to the touch. This can take a week or more. Squeeze a piece of the hash and feel for any moisture on your fingertips. When no moisture is present, the bubble hash is ready to go.
(36) Best Ways To Dry Bubble Hash
(37) How Does a Freeze Dryer Work?
Pressing Bubble Hash Rosin
3 and 4-star hash is ideal for pressing into rosin. 1 and 2-star is better suited for edibles, and 5 and 5-star can be dabbed as it is (38).
25-37 microns is the recommended filter size for rosin bags when pressing bubble hash. Bubble hash is loaded into the rosin bags the same way as sift and flower, packed tightly to eliminate empty pockets within the material, but not so tightly that rosin cannot flow out from the center. It should feel dense and very compressed when squeezed between the fingers. For both flower, sift, and bubble hash, pre-press molds help to further compact and prime the material for extraction.
As with dry sift, double-bagging for bubble hash is helpful in preventing blowouts due to the high volume of rosin that flows quickly from the hash under heat and pressure. A larger micron such as 120 or 160 is often used as the outer bag, but the recommended 25-37 microns for sift will also work doubled-up. If using different microns, the larger micron should be on the outside.
160-190 degrees Fahrenheit with Platen PSI between 350-750 are good ranges in which to experiment with bubble hash rosin. And with any type of rosin extraction, be sure to start with a lower PSI and gradually increase to full pressure over time (39).
(38) How Hash Is Rated
(39) Top 10 Hash Rosin Pressing Tips
Rosin is ready to consume immediately after production, but a curing process can help enhance the flavor and stabilize consistency. Curing rosin involves the use of an airtight glass jar, such as a mason jar. This approach to curing rosin is known as Jar Tech, and there are two types of Jar Tech (40): Warm Curing and Cold Curing (41).
Warm Curing involves exposing the rosin to temperatures anywhere between 90 and 135 degrees Fahrenheit (42). This can be accomplished in an oven, or even with a heating mat similar to what is used for warming cannabis cuttings.
Cold curing is often done at cool room temperatures, in the 60-degree Fahrenheit range (43). Cold curing often preserves more of the volatile terpenes in rosin than warm curing. With both types of curing, keeping the lid sealed for the duration prevents terpenes from evaporating into the air.
The lid can be “burped” intermittently during the cure, and some extractors like to “whip” the rosin as well. Terpenes often separate out naturally during the cure, and whipping helps to reintegrate the liquid terpenes back into the rosin.
(40) How To Jar Tech Rosin
(41) Cold Curing vs Warm Curing Rosin
(42) Top 10 Warm Curing Rosin Tips
(43) Top 10 Cold Curing Rosin Tips
(44) What Are the Benefits of Whipping Rosin?
Rosin can be stored for many months in glass containers with an airtight seal (45). Using glass to store rosin is key, since glass doesn’t interact with terpenes in the way that plastic or silicone does. Both plastic and silicone as susceptible flake away and leach into the rosin over time, as terpenes are actually a natural form of solvents. To preserve the natural state of the rosin, be sure to only store it in glass for the long term.
Store rosin in a cool, dark, and dry environment. If storing in the refrigerator or freezer, be sure to allow the jar to come to room temperature when removing for use first before cracking open the lid. And wipe away any condensation that forms inside the glass, in order to prevent moisture from getting into the rosin. Bubble hash and sift can be stored following these same principles. Bubble Hash can also be heated and rolled into a Temple Ball (46) for long term storage and aging (47).
(45) How To Properly Store Rosin
(46) What Is a Bubble Hash Temple Ball?
(47) What Is the Purpose of Aging Bubble Hash?
Rosin is most commonly dabbed with a dab rig and heated nail or bowl (48). To optimize for the most flavorful smoke, use lower temperatures at the nail. If you prefer the ease and convenience of vape pens, rosin can be used to make vape cartridges. This requires extra steps to decrease the viscosity of rosin, but it can be done (49).
Rosin can also be used for making edibles or other infusions, like MCT Oil capsules. You can even add rosin to joints for enhanced flavor and potency (50).
(48) How To dab Rosin
(49) How To Make Vape Cartridges with Your Rosin
(50) Best Ways to Use Rosin
Unlike cannabis concentrates that utilize solvents for production (e.g. CO2 in closed-loop systems), solventless extracts like bubble hash and rosin are safe and easy to produce right from home, with minimal investment in equipment and starting material. Growing your own cannabis allows you to produce quality starting material and is often the most economical way to create a steady flow of top shelf cannabis concentrates. Solventless concentrates capture the essence of the plants from which they’re produced, delivering a pure, potent, and flavorful experience.
Getting started is the hardest part. Once you start gaining some hands-on experience, you’ll quickly learn as you go and improve your process and your results. Take good notes along the way, learning from both your successes and so-called failures (51).
What are you waiting for? Start your solventless journey and start rosin pressing today!
(51) How To Take Notes to Improve Your Rosin Production
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