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How to prepare hemp for screw press cbd oil extraction

How to prepare hemp for screw press cbd oil extraction

March 24, 2021

A previous issue of this newsletter described a turn-key hemp oil production plant which was designed and built by our affiliate, Plant Works Group, for a customer in the southeast. Those are facilities which cost in the seven figures.

Many operations in the industry start on a smaller scale. For them it works out most economically if they follow Do-It-Yourself steps.

Right now EtOH extraction with a screw press is the cheapest and easiest way they can make a product. Screw press extraction gives approximately 95% efficiency of CBD oil removal from the hemp biomass.

An important benefit of using a screw press is that it maximizes alcohol recovery. Our model CP-4 screw press has proven to be an excellent screw press for newcomers to cut their teeth with. Washing with a 3:1 ratio, 85% ethanol recovery is achieved.

Downstream processing can get quite complicated. Or, it can be done in a fairly rudimentary way, inexpensively, as an introduction to refinement. The next steps are:

Step 1:
Alcohol coming through the 150 micron wedgewire screen of the screw press is pumped to filtration equipment. Bag filtration works well. Stepped bags, starting with 100 micron, 60 micron and then 10 micron fabric, are recommended. A polishing filter with 2 micron medium is used for the final step.

Pressure vessels are ideal, although we see plenty of people who just allow gravity to do its work.

Step 2:
Activated carbon filtration is needed to take out Chlorophyll.

Step 3:
Winterization (deep chilling) is used to remove lipids, fat and waxes. This is a time and temperature process. Some of our customers get away with dry ice, if they can get it cheaply or produce it themselves. Otherwise they will need either a large freezer, capable of -20C to -60C (or even lower), or a jacketed tank with an associated chiller.

Plant Works Group recently bought a two stage (compressor) chiller on Ebay. It is a -80C chiller, and it cost us around $20,000. This, hooked up to a jacketed tank, would do the job. With the right temperature and time, the waxes will precipitate, allowing for removal by filtration. You have to take out the waxes and lipids or the finished product will not be acceptable.

Step 4:
Ethanol Recovery: An inexpensive approach is a large 50 liter rotovap. These cost around $10,000, as a guess. A less expensive chiller would be used for condensing EtOH. The more expensive approach is a small scale kettle or falling film evaporator ($100k+).

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Step 5:
Decarboxylation or Decarbing: The crude must be heated to 70+C for a period of time. This is done to convert CBO-A to CBD. The CO2 is exhausted. It is important to evaporate the alcohol under a vacuum, to prevent oxidizing some oils.

Once the solvent is removed, the temperature is held, under vacuum, long enough to get an active CBD product.

At this point a winterized, decarboxylated crude oil with all residual EtOH removed has been produced. The industry refers this as CBD crude oil. It is a very thick black fluid at room temperature. At temperatures over 120F this turns to a water-like consistency.

Distillate is the honey gold colored oil, near enough to be a pure CBD product.

Step 6:
For around $5K a single mantle glass distillation set-up will produce around 1 liter of 80% – 85% CBD distillate per day. This is done at high temperature and a deep vacuum, 175C and 50 mTorr. Under these conditions, residual solvent, humidity, and terpenes are boiled off and stored separately from the distillate.

In a nutshell, newcomers need to get their heads around the above set-up for lab scale, minimum expenditure, processing. If they don’t have $25,000 – $50,000, in addition to the screw press, to spend on some essential equipment, then they will be hard pressed to make a finished product through this solvent extraction process.

The above is a good first phase in the learning process. Once the newcomers master this and develop some SOPs that work for them, they will be able to embark on scaling up. A recommended option is to engage an engineering firm like Plant Works Group to expedite the path to the market.

Practical experience in this industry is vastly underrated by new money; they always think that they will be fine. The bottlenecks and hurdles are fairly cumbersome.

Making Hemp Seed Oil: A Simple Guide To How It’s Made

As CBD oil’s lesser-known cousin, hemp seed oil provides its own unique set of health benefits and its own special manufacturing methods. Since its discussed less often, we thought we would take a closer look at hemp seed oil.

Coming specifically from hemp seeds (duh), hempseed oil is commonly confused with its uber-popular counterpart, CBD oil. While CBD oil is a health powerhouse in its own right, hemp seed oil also carries with it plenty of health benefits. It has a rich nutrient profile, lots of good fats and fatty acids and carries a wide range of nutrients. Hemp seed oil can help skin health, inflammation, brain & hearth health. Hemp seed oil is a worthy addition into anyone’s diet.

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You may know that CBD oil extraction involves complicated machines that use different solvents such as C02. We thought you’d want to know how making hemp seed oil compares. Below we’ll outline how hemp seeds are commonly extracted and even how you can make your own oil at home!


All seed oils are extracted with an oilseed press machine, and hemp seeds are no different. Used for edible and industrial oils, the oilseed press machine is a trusty & sturdy machine for oil extraction. Seed press machines usually come in two distinct types: a traditional screw press or a reducing screw design.

Making hemp seed oil, or any seed oil, involves a seed press. The details can get complicated, however.

A lot of variables go into the specific pressing of different seeds, but the main concept stays the same. First you dispense raw seeds into the seed hopper, then an expeller screw crushes the seeds. Next, the oils run through canals where the pulp gets separated from the oil.

The oil produced from this method is pure, raw and as unprocessed as modern technology can get. And this is the basic & traditional method of extracting oils from seeds. This basic method and machinery are used for all kinds of seeds and even nuts. Oils from peanuts, sesame seeds and of course hemp seeds are extracted by this method.


While the traditional oil press method seems simplistic, it’s actually surprisingly complex. Many variables go into seed pressing that can make or break a batch of oil.

Let’s take seed moisture content for an example. If a seed is stored incorrectly and it harbors a higher-than-normal moisture content, then it will not press well. This is because if a seed is pressed with too much moisture, the moisture will actually tie up the oil within the seeds. Problems arise with moisture levels that are too low as well. That will increase the pressing temperatures, leading to lesser oil production and potentially going above the temperature limit for “cold-pressed” oils (120°F). Even something as simple as storage can impact the way the seeds interact with the press machines, which is why it’s important for manufacturers to pay attention to every part of the process.

Seed quality is another important characteristic. Non-ripe seeds produce different quality oils and smells than ripe seeds. And obviously seeds that are moldy and improperly stored will produce low-quality oil. The actual operation of the seed press is important too, as the settings for the machine greatly affect the pressing method and pressing temperature. An operator must know how to manipulate the distance between the press head and the screw end, the speed of the press, the tip size and the type of screw needed for the seed. This is why having a well-experienced seed press machine operator is important for companies looking to produce quality hemp seed oil products.

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The reason a “cold-pressed” oil is preferred over others (even though it produces less oil) is that it tends to keep more of the characteristics and benefits of the seed in the final oil.

Cold pressing also produces lower phosphorous levels. phosphorous is the culprit for the “green” and “grassy” flavors of some oils. If this is something you dislike, then cold-pressed oils are for you.

The complex process of creating cold-pressed seed oils requires a surprising amount of expertise and precision.

Heat and the distinctive characteristics of the oil it produces affects the quality of CBD oil too. Most CBD extraction methods require heating and pressurizing chemicals to supercritical temperatures. If you want an oil that keeps the majority of the plant’s original characteristics and fats without the ‘grassy’ taste, then cold pressed oil might be a good match.


If you’re like us, you can’t afford to buy an industrial scale oil press machine. You might still want to experiment with making your own seed oil. If so, we suggest you purchase a hand crank oil press. Not only can you make hemp seed oil, but you can press any type of seed or nut that you want.

Making hemp seed oil on a hand crank seed press is easy. First, set up the press on a flat, secure surface. Next, you’ll fill the attached oil lamp and light it for 10 minutes prior to operation. This warms up the crank and ensures the oil separates. Then, simply put seeds into the hopper and crank away!

That’s the basics of how to make hemp seed oil. We hope that the next time you see seed oils in the store, that you have a little bit more appreciation for all the hard work and precision that goes into making them.