58 minutes | Feb 16, 2021

S1 E09 - Crystallization Of CBD Isolate

Luke Van Trieste of BR Instruments joins us to discuss CBD isolate crystallization. We get deep into the equipment, solvents, and SOPs used to crash out those crystals. We cover static and dynamic crystallization, as well as the continuous flow processes that are beginning to come online. In addition to the BR Instrument crystallization reactors, we discuss their patented spinning band distillation equipment.EPISODE TRANSCRIPT:Jason Showard - 00:00:10 Hello and welcome to Episode nine of The Modern Extractor. This podcast focuses on the processes, equipment and science found in a cannabis extraction laboratory. I'm your host Jason Showard, and I work professionally in the cannabis extraction field. Here in season one, we're focusing on ethanol extraction and post processing, with each episode digging into a particular stage in that process. The shows are released in an order that follows the workflow through a lab as material makes its way from cultivar to concentrate.  Jason Showard - 00:00:39 Last week we had Jay Horton on the show. He's the founder of Genovations and the man that got me started distilling cannabis. We talked specific SOPs for wiped film and rolled film distillation. We went through how to push your machine to the absolute limit and get the maximum throughput out of a wiper. He hit us with a ton of distillation knowledge gained from his years of experience in the trenches cranking out liters, as well as his experience installing and training on Chemtech equipment.  Jason Showard - 00:01:05 Moving on to this week's show, let's catch back up with a work in progress. So far, we've performed a cold ethanol extraction in a centrifuge. We've cold filtered the resulting miscella through a lenticular filter. We ran the filtered miscella through a falling film evaporator to separate the oil and the ethanol. We decarboxylated the crude oil to convert the cannabinoids. We terp stripped, then we distilled the oil, creating some beautiful golden distillate. As I said last week, distillate is the end of the line for THC.  Jason Showard - 00:01:34 But today we'll take CBD distillate a step further in the purification process and crystallize it into 99.9% pure CBD isolate. Joining me on the show today is a man who has processed many a kilo of isolate. He's very well versed in the equipment, solvents and processes of CBD crystallization. He's usually found flying around the world installing and training on BR instrument crystallization reactors, as well as their patented spinning band distillation equipment. He certainly knows his way around a cannabis extraction laboratory.  Jason Showard - 00:02:06 Luke Van Trieste, welcome to The Modern Extractor.  Luke Van Trieste - 00:02:09 Hi, thanks for having me.  Jason Showard - 00:02:10 Absolutely. Where are you calling in from today?  Luke Van Trieste - 00:02:13 I live just outside Baltimore, Maryland.  Jason Showard - 00:02:15 Right on. You were telling me earlier it's a snowy day out there. It's a rainy day here in Los Angeles.  Luke Van Trieste - 00:02:21 Yeah, plenty of bad weather lately this winter.  Jason Showard - 00:02:25 So talk to me a little bit about your path to joining BR instruments.  Luke Van Trieste - 00:02:31 So this is actually my 10th year at BR Instrument. I basically started off in high school doing graphic design content and creating marketing materials. I worked there through most of high school and college, until I got my degree in chemistry. And then I transitioned into my role, into doing installations and trainings. So if you buy a piece of our equipment, there's a very good chance that I'll be the person that's actually there, you know, running you through the show. So, yeah, 10 years. It's exciting.  Jason Showard - 00:03:08 So give us a bird's eye view of BR instrument as a company. How'd its start? Where is it now?  Luke Van Trieste - 00:03:14 So we produce mostly spinning band distillation equipment, which is really useful for high purity applications or for difficult separations. So we see a lot of work in the petroleum, the pharmaceutical, environmental, analytical industries. And obviously, you know, cannabis and hemp has become a very big part of our company as well. So we really just, any kind of distillation is pretty much our wheelhouse.  Jason Showard - 00:03:40 All right. So are you guys primarily working right now in the cannabis and hemp industry or are you spread out amongst all of that currently?  Luke Van Trieste - 00:03:50 We're spread out amongst all of that currently. So we do a lot of international business as well, which probably represents about half of the total business for us. And at this point in time, at least, there's not a ton of cannabis and hemp, although it's starting to pick up around the world. But that may be another couple of years while other countries figure out, you know, imports and exports and stuff like that.  Luke Van Trieste - 00:04:16 So I'd say cannabis is about, domestic cannabis, is about half of it. And the international, that basically encompasses all the other things I mentioned. It's probably about the other half of it right now.  Jason Showard - 00:04:28 OK, I've been intrigued by your spinning band distillation for a while now. Last week on the show, we covered, actually the last couple of weeks on the show, we covered distillation of cannabinoids with a rolled film distillation unit. While this show is technically about CBD isolate and crystallization, I think while I've got you on the line here, it makes sense to go over spinning band a little bit. So tell me a little bit about spinning band. How does it work?  Luke Van Trieste - 00:05:01 So if you're familiar with the colloquial, short path distillation. So by that I mean a small flask with a short little column, and basically a very simple distillation model. And not in reference to a wiped film or a rolled film distillation with appropriate pressure. So like Lab Society or Summit or one of many other companies produce those short paths. It functions more similarly to that than a wiped film.  Jason Showard - 00:05:33 Yeah, I've on the show here previously. I've referred to those as a tabletop short path. While the rolled or the wiped film still technically a short path, I believe you're referring to the tabletop short path, correct?  Luke Van Trieste - 00:05:45 Correct. So basically we are a batch process where you're going to at the beginning of the run, fill up your flask with your starting material and then you're going to heat it up. And then by using different boiling points of the different compounds in there, we're going to slowly separate them out. And basically how we do that is, the way to separate a vapor from a liquid is to have them interact more. Strangely enough. And that's going to enrich both of those phases in their majority component.  Luke Van Trieste - 00:06:19 And so a spinning band. What we're doing is by highly agitating the column area, as vapors come off of the boiling flask that we've been heating, we're greatly agitating these vapors and making them slam into the liquid and along the wall of the column, and basically forcing tons of interactions with a very high refresh rate.  Luke Van Trieste - 00:06:42 And that gives you the highest purity out of fractional distillation. And so a comparable method would be, for like a tabletop short path, if you put in a packing substrate. And that basically gives you a surface area for the vapor liquid interaction. So a spinning band, it's a dynamic interaction where that surface is always being changed, it's constantly being refreshed. And there's definitely some other advantages too. Such as a spinning band is going to have generally a higher throughput for the purity that you get. Because as the cycle of boiling and condensing happens, the helix of the spinning bands pumps the rejected liquid that has been condensed back into the boiling flask to start the cycle over again.  Luke Van Trieste - 00:07:32 But vapors are basically able to travel relatively freely up the column because there's a large open space. It's just moving. So there's a couple of advantages. But purity is definitely the name of our game.  Jason Showard - 00:07:48 Yeah, I've basically from talking to you guys at the trade shows and reading on the Internet, the amount of theoretical plates that can be created with these is pretty impressive, but something that you really don't run into with a wiped or a rolled film unit. That would definitely be the upside. Now, I've heard some people in the industry say that a downside to a system like this or to your traditional short path is going to be something like residence time. What do you say to that?  00:08:18  I say that cannabinoids aren't as fragile as people like to make them out to be. I think that, you know, frequently people take maybe a little bit too much care. I think a lot of it has to do with the type of product that you're trying to make. I'd say that the maximum temperature is almost more important than your residence time. And basically the thought process behind that is a general rule of thumb for chemistry, is that by every 10 degrees Celsius you raise the temperature, you cause a reaction to happen twice as fast.  Luke Van Trieste - 00:08:55 So taking twice as long is effectively the same thing as doing something 10 degrees hotter, from a chemical reactions perspective. So I think, you know, if you're really concerned about residence time, I think maybe you should look at the maximum temperatures that you're incurring first instead. And as long as you're below 200, 190 Celsius, you're really not going to see a ton of stuff.  Luke Van Trieste - 00:09:22 The funky things start to happen at about 210 to 220 degrees Celsius, in my experience. That's where you'll start to see more and more rapid degradation.  Jason Showard - 00:09:32 OK, so with your style machine, also, the way that it functions, you're going to end up with the lighter stuff, which is typically more fragile, coming off first and getting out of there before the temperature rises anyway for the most part, right?  Luke Van Trieste - 00:09:50 Yeah, absolutely. We do a decent amount of terpene processing, too, as well. Which involves using virtually no heat and just vacuum. And so instead of heating something, we can just reduce the pressure which will cause us to distil over. And with terpenes, they tend to be quite low yielding, but for that very reason, you want to be very careful with them and very gentle with them. And those can be removed first in kind of a separate process, but still on the spinning band.  Jason Showard - 00:10:18 All right. Well, I'm glad we got a chance to kind of jump into that. I've wanted to talk to you guys about spinning band and had thought about reaching out regarding that. And then, you know, when it came up to reach out to you regarding crystallization, I figured it was a great opportunity to do that. So the reason that I reached out to you specifically about CBD crystallization is because of a blog post that you wrote back in early 2019 on the BR Instrument blog about creating CBD isolate.  Jason Showard - 00:10:47 It was full of equipment, knowledge and SOPs and just basically a really nice, informative package. In addition to the post afterwards, people started commenting and you were jumping right in there and responding to everybody's questions in the comments. I think that's great and really aligns with my approach here at The Modern Extractor, which is to kind of curate and release the best information possible to the audience. So because of that, I was excited to talk to you and I'd like to move on to the actual science behind the final stage in the process we've been covering this season, which is crystallization.  Jason Showard - 00:11:20 So let's talk a little bit about what we're trying to produce here. CBD isolate is purified, crystalized CBD. Let's break that down. So what is a crystal?  Luke Van Trieste - 00:11:31 So a basic overview of what a crystal is, is that it's going to be a solid that has its molecules in an organized long-range structure. And so I think it's important to talk about things that are not a crystal, so a very common example is a glass. Glass is clear, it's pretty. You can cut it into a crystal, but that doesn't make it structurally on the molecular level, a crystal.  Luke Van Trieste - 00:11:58 Another example is going to be like some kind of plastic or wax where, you know, these are very big molecules that kind of interact with each other in a much different way than a nice crystal lattice. I think it's also important to point out that a lot of natural substances are polycrystalline. And basically that's going to mean that you took a bunch of individual crystal structures, grew them together, and then they fused. So this is going to cover, you know, metals, some rocks or a ceramic, for example.  Jason Showard - 00:12:30 OK, so with those things that you were just talking about, for example, the metals, the rocks, the ceramic, that is, they were crystalline in nature prior to having a bunch of these crystalline structures formed together and then fused due to heat or some other environmental conditions? Pressure?  Luke Van Trieste - 00:12:50 Yes, you can almost think about the way they fused together as a joint. And so frequently that's where a weak spot in the crystal may form, is at the interface of two of these different sub crystals. And so you can call gold crystalline in some context, but you're not going to have a gold crystal, if that makes sense. It's going to be quite small, realistically.  Jason Showard - 00:13:14 OK, so solubility is an important concept when it comes to crystallization. Talk to us a little bit about the relationship between solubility and crystallization.  Luke Van Trieste - 00:13:28 So solubility is going to be in this case, how much CBD can we jam into a given solvent at a given temperature? And there's ways to change that. An important way is temperature. So as you increase the temperature of anything, it's going to become more soluble. And if you decrease the temperature, it's going to become less soluble.  Luke Van Trieste - 00:13:54 So we want to, our goal is to basically create a solution that has a lot of CBD in it and that's going to be called "saturated." So a saturated solution is when we get to the point where if you add more CBD, it doesn't dissolve anymore, it just kind of sinks to the bottom of the container. Then you can also have a supersaturated solution.  Luke Van Trieste - 00:14:15 So this is going to be a solution that has more CBD than it should technically be allowed to at that temperature. And how we create that is you elevate the temperature to dissolve a lot of CBD, but then through some controlled method, you reduce the temperature without crystalizing any of the CBD out of solution. Suddenly you have CBD that's just maybe a little bit thermodynamically unhappy to be there at this point, but it's not quite ready to crash out.  Jason Showard - 00:14:44 OK, well, before we get further down the road into the SOPs of crystallization and specific stuff about equipment, let's talk about solvents for a moment here. While you're talking about solvents, there's a variety of them that can be used for crystallization. Are you making solvent decisions based on solubility or is that more of a boiling point or regulation or a safety decision?  Luke Van Trieste - 00:15:09 So primarily the issue is solubility, because if it doesn't crash out at some point or you can't dissolve any of it, then that's just kind of a non-starter. So our solvent of choice really needs to have a couple characteristics regarding solubility. So the first one is that CBD needs to dissolve into our solvent well, at an elevated temperature like I mentioned. However, at decreased temperatures, when we start to cool our solution, CBD needs to become relatively insoluble. If it stays too soluble at a low temperature, then we're not going to get crystal formation.  Luke Van Trieste - 00:15:49 The final solubility consideration is what is our waste product consisting of? So if we have THC that needs to be removed from these CBD crystals so you can sell them internationally, then you need to make sure that your solvent of choice also carries THC quite well at low temperatures, not just high temperatures. Otherwise you're just going to end up with kind of a goo coating your crystals as it will crash out, but not really crystallize either.  Jason Showard - 00:16:20 Some CBD sauce.  Luke Van Trieste - 00:16:22 Yeah. So that's how you
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