How to make THCA Crystals & Solventless Sauce

Why isolate cannabinoids?

In recent times we've seen a great increase in the amount of isolated cannabinoids coming onto the market, with CBD crystals and pure THC distillate becoming a more frequent sight on the menus of dispensaries. Their popularity is mostly due to the ease of calculating dosage amounts. While the vast majority of resin extracts have an unknown cannabinoid content, when we isolate a cannabinoid, users can be confident that they have a product with a purity approaching 100%, which makes it very simple to adjust dosage to a specific amount of milligrams. This is particularly important when preparing edibles, tinctures or other products for oral consumption, where knowing the cannabinoid content is vital to avoid any ill effects caused by ingesting too much THC.

Pure Solventless THCA Crystals
THCA Crystals isolated using this method

For the most part, these isolated cannabinoid products are the result of complex processes that employ expensive equipment, volatile chemicals and in-depth, specialist knowledge that are far out of the reach of the average home grower, extraction enthusiast or fan of cannabis concentrates.

THCA molecule
THCA molecule

However, over the last year, new techniques have come to light that enable anyone with a rosin press and some good quality starting material to produce their own isolated THCA, the un-decarboxylated, acid form of THC. It is a very simple mechanical separation process whereby "budder" or "wax" textured rosin is re-pressed at low pressure and low temperature, through a fine mesh filter, extruding the terpenes, waxes, lipids and secondary cannabinoids, and leaving behind more-or-less pure THCA inside the filter. Over the following paragraphs we'll explain how it's done. First, if you want, check out our earlier blog post for some basic tips on how to use a hydraulic rosin press.

What you'll need:

  • Rosin with a wax or stiff budder texture (for best results use rosin from fresh frozen bubble hash)
  • Rosin filter bags - 25 or 37 micron
  • Parchment paper
  • Manual rosin press with temperature control (air-assisted presses rarely have the delicacy needed to press at low pressure)

The importance of rosin texture

To carry out this process successfully, the rosin we use as starting material must be in "budder" or "wax" form, a phenomenon which occurs as a product of THCA nucleation. Basically, the THCA molecule is a pseudo-polymorph, meaning it is able to change and crystallise into different forms under certain conditions of pressure, temperatures, and depending on the interactions between the solvents (in this case the various terpenes), the solutes, (the cannabinoids) and any impurities present (for example plant fats, waxes and lipids). This can cause the THCA within the concentrate to crystallise and form a stiff, hard wax or budder texture and, in some examples, "crash out", or separate itself from the other elements in the extraction, such as in the case of sugar wax, which takes on the consistency of wet granulated sugar as the THCA crystallises and separates from the terpenes, secondary cannabinoids, fats and lipids.

Buddered Flower Rosin
Rosin agitated to produce a budder texture

These textures are more often experienced with high purity extractions of varieties with high terpene content, as well as with fresh-frozen bubble hash extractions, also due to the high levels of volatile terpenes, which not only offer a much more intense flavour and aroma, but when the bubble hash is pressed into rosin can often cause the rosin to nucleate and become budder almost as soon as it oozes out of the filter bag.

In the right conditions, stubborn rosin can be persuaded to nucleate to some extent and form a loose budder via heat and agitation, for example stirring with a dabber over a heating mat or hot plate set to 50ºC or less. This method has worked successfully although degradation of terpenes is inevitable when the extracts are exposed to this temperatures of this kind.

Preparing the starting material for separation

Once we've got our wax/budder rosin in the right state, it's time to start preparing it for the separation process. Now is a great time to switch the rosin press on and set the temperature of the plates to 55-60ºC (130-140ºF). For faster and more uniform heating keep the plates pressed together as they get up to temperature.

Packing the rosin in screen
Preparing the rosin for separation

For separation to work properly, we need to enclose the rosin in a tight mesh screen, ideally this will be a 25 micron rosin bag although 37 micron bags will work fine, and if we've got neither of those to hand, an unbleached paper coffee filter can be cut down and used instead. Pack the bag with the rosin, fold the opening over and cut off any remaining material.

Next we place the rosin, now a tightly wrapped parcel in its filter bag or paper, into a folded, pre-cut sheet of parchment paper, and we're ready to begin pressing.

Applying pressure

Open the pressing plates enough to insert the folded parchment with the rosin parcel, so that it is centred with the open end facing outwards, towards you, so you'll be able to see as the terpene-rich sauce oozes out.

Terpene-rich sauce oozing from the filter
Terpene-rich sauce escaping the filter

Now carefully close the plates until they just make contact with the parchment and its contents, but without exerting any pressure, and wait for 20-30 seconds for the rosin to warm up and start to melt. Begin to apply pressure very slowly and gently to avoid bursting the bag, and very soon you should see liquid resin dripping from the plates on to the collection paper. Once you've reached maximum pressure, hold it there for up to a minute, or until the sauce stops dripping out. Open the plates, take everything out of the press and put the parchment carefully to one side, keeping the rosin parcel for the second pressing.

Opening the mesh to find the raw THCA

Now repeat this process with the temperature raised to 80-90ºC (175-195ºF), using a fresh piece of parchment to collect the sauce (there will be less this time, and it's usually less runny). After this second press, remove everything from the plates, allow to cool and carefully open the filter parcel that held the rosin. You should have a white, or very pale yellow substance with a chalky texture. You can press it again at a slightly higher temperature if you'd really like your THCA to be more pure and lighter coloured.

If you're separating the THCA for the purpose of accurate dosing for edibles, topicals and other applications requiring precise measurements, it is now ready to use in this state. If, however, the plan is to make some "diamonds and sauce" to dab then a little more polishing will be needed to get the finished product.

The final stage is to place the chalky, raw THCA on the plates on some parchment and melt it without applying pressure, so it liquifies and forms a pool (this can require temperatures upwards of 120ºC) . Carefully remove from the heat and allow to cool, so it can stabilise, when it will assume a much more visually attractive crystal-like texture once broken into smaller pieces. Now, using a little heat to reduce viscosity and facilitate mixing, we can re-combine some of the THCA crystals with a little of the terpene-rich sauce that we separated earlier to create the famous Solventless Sauce & Diamonds extract that has caused a sensation on Instagram over the last year, and not only is it spectacular to look at, but also very tasty and potent indeed!

THCA Crystals added to the sauce
The finished product: THCA Crystals recombined with the terpene sauce

In a future article, we'll take a look at a new method of creating Solventless Sauce and Diamonds that gets similar results also using heat and pressure, but in a very different way. Till next time, happy extracting!

Comments in “How to make THCA Crystals & Solventless Sauce” (7)

Great read. Thank you for sharing your work! A fan.
Evan M
Can you use filter bags above 37 micron? Say 90 microns for example.
Tim Alchimia
Hi Evan, thanks for your question. I wouldn't recommend using larger micron filter bags to attempt mechanical separation of this sort. In fact, 37 microns is even a bit large for my personal preference. Ideally, I'd use 25 or 15 microns for all hash rosin and THCA separation, simply to increase purity and, in the case of the mechanical separation, to retain more THCA. I'd only ever use a 90 micron bag for pressing flower, or as a second bag to reinforce the 25 micron against blow-outs. So to sum up, it's 15, 25 or 37 microns for hash and THCA separation, anything larger than that is only useful for pressing flowers. I hope that clears things up for you. All the best and happy pressing!
Relationship Problems
Important information. I would like to share your blog with friends. It looks very awesome.
Tim Alchimia
Hi, thanks for the nice compliment, please feel free to share our blog with everyone you know! All the best.
Silence Dewgood
Hello, This is a fantastic article! I am a natural product chemist and this is valuable information that you are providing. Thank you. I am curious, how do you know that the final product (without the readdition of terpenes) is only THCA? Would it be possible that CBD is present as well? What about other cannabinoids found in rosin? If possible, would you be able to provide lab testing results of the constituents in these crystals? I realize these are many questions, so I am happy if you are able to answer any of them.
Tim Alchimia
Hello Silence, thanks for your comment and question, we're very happy you enjoyed the article! As for your question about the possibility of other cannabinoids being present in the crystals, as much as I'd like to, I haven't had any lab tests done on the end product (here in Spain cannabinoid & terpene testing is still in its infancy and while there are labs doing reliable tests on flowers, I don't know of anyone doing accurate testing of extracts yet) so any estimate of the final cannabinoid content would depend mostly on the chemotype of the cultivar being processed. In this case, we used a high-THC variety, so any secondary cannabinoids would only have been present in trace amounts. In addition to this, and as far as I understand it, CBD behaves differently to THC in that its raw, un-decarboxylated form CBDA it has a viscous, oily texture while once decarbed, CBD takes on a crystalline form, which is exactly the opposite to THCA which is a crystal and decarbed THC which is a thick oil. In short, yes, there may well be trace amounts of secondary cannabinoids in the THCA crystals, but the chemotype of the starting material along with the crystal texture indicates that we're dealing with almost-pure THCA here. That said, I'd love to have access to a trustworthy lab to verify this! thanks again for the kind words, all the best and happy extracting!
Very good info. Just what I'm looking for. You said you had another method for crystals. When will you post that info? Inquiring minds and all that.
Tim Alchimia
Hi Phread, Thanks for asking, nothing just yet I'm afraid, I'm still experimenting with the method, but if you want to look into it yourself, try a google search for "Jar Tech".
Great response Tim, new fan here!
Tim Alchimia
Thanks for your kind words, they mean a lot!
margie ridgen
Have you ever heard about these foods infused cannabis? I tried frozen yogurt infused cannabis before and it really tastes good! and now, there's new and something interesting! On the other hand, Ingesting Cannabis has a side effect that can lead you addiction because of its high dosage that you'll never know how much dosage that food has. By continually do researching, I came across in this article about strains
Tim Alchimia
Hi Margie, thanks for your comment. Yes, here we're big fans of cannabis.infused foods, they're a great healthy way for non-smokers to medicate and are essential for some therapeutic patients who can't consume cannabis in any other way. However I must correct you, you're wrong when you say that Cannabis can lead to addiction. That's a completely false statement with no basis in science. Cannabis use, unlike caffeine, nicotine or alcohol, does not lead to physical dependency. It can however be habit-forming, which can cause issues just like other modern-day "addictions" like gambling, shopping, social media etc. which are all non-physical dependencies, and a subject for psychologists rather than physicians. I hope that's helped to clear things up. All the best!

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