Color of Bulk Distillate : Why is it so dark?

by Luke on March 25, 2020

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When buying cannabinoid products in bulk,  you will often find yourself thinking about the color. Color can be an important indicator of quality in some cases. No one has any desire to consume a concentrated black tar. Color is not the only indicator of purity though. Test results from a certified lab should do most of the talking. Here is some background and some advice for those producing/buying bulk THC or CBD distillate.

THC Vape Cartridge

Beer-Lambert Law

To break this down quick and dirty, you need to focus on three of the letters. A, C, and L.

A = B * C * L

Where:

  • A is the absorbance. You can think about this as a measurement of light blocked.
  • B is a property of the compound using a specific color
  • C is the concentration of the compound
  • L is the path length or total distance light travels through this substance.

The gist of this equation is that there are ways to change the color and appearance of substances! They may seem so obvious that it is easy to not even think about them.

The first method is to change the concentration of the substance. If there is a higher “density” of a compound, the more light it will absorb. The example here is that if you dissolve crude at a ratio of 1:1 in a solvent, that will look different that something at a ratio of 10:1. Simple enough. The second is to change the path length. You can think of this like a viewing distance. Even crystal clear water blocks tons of light just a few feet below the surface. Again, if you are looking through more of something, more light will be blocked.

This is great! Now you understand over 75% of how a UV-Vis spectrometer works. Specific colors of light interact with certain chemicals in a predictable and reproducible way.

Take Away

The point being that in say a vape cartridge, an oil may look light. In bulk however, the color is often much more apparent. When buying and selling distillate, it is important to consider the bulk appearance versus in a small container. Does the oil look clear and have very little color even in a large jar? Then the quality is likely very good. As always however, the CoA or ‘certificate of analysis‘ speaks for itself. Very high potency distillate (95%+) can have strong color. It will generally still have good clarity though, meaning there will not be streaks or other contaminants in your product.

Bulk distillate versus small batch appearance comparison

The same oil in two different volumes. Now imagine how light the color would be in a vape cartridge!

THC Distillate in Syringe

While training new users on spinning band distillation systems, I say that you can expect the color of the “side-arm” to be a good indication of what a vape cartridge will look like once filled. Always remember that of course lighting has a lot to do with appearance and so does the backdrop.

THC Distillate 1THC Distillate 2

Posted in cannabis-distillation, Hemp Processing

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9 Comments

  • Hi ! I have a question about Delta 9 THC vs. Delta 8 THC in terms of their color.

    I’ve been seeing so many more of these distillates lately, where their color is crystal clear with a slight purple tinge.

    Traditionally, I’ve worked with high potency Delta 9 THC distillates, with COAs and lab results coming back at 97-98%, and this stuff is clear, but it is by no means “void of color clear”. And like you say, in bulkier volumes the color appears much darker, like an orange or amber. In a smaller volume like a cartridge its a nice and clear yellow. When this product oxidizes, it turns even darker orange & amber.

    My question is, Is it possible to have Delta 9 THC distillates that appear this way too? Or is it safe to assume that all of these crystal clear white/purple distillates must be Delta 8 THC?

    Thanks 🙂

    • Hi Amanda,

      I have heard the appearance of pink or purple distillate is due to the pH.

      Generally, “water clear” distillate is made using the use of some acid activated media. The media used works well at “bleaching” the crude or distillate. It works in several different ways, and often a combination of different types of media is used.

      Delta 8 THC is made by the use of some acid. Whether you use an acid directly as a reactant or use some acid activated media, the relative acidity/basicity of your THC will be altered.

      What I am getting at is that the creation of delta 8 THC is often just an indirect consequence of using techniques to improve the color/clarity of the oil. Originally people were just remediating their otherwise less valuable product and getting delta 8 THC as an unwanted product.

      The production of “water clear” Delta 9 THC is possible, but requires some careful chemistry. And to top it off, you must have a balanced pH before you attempt to distill the delta 9 THC. Even in the scientific literature, many cannabinoids are reported as having some color.

      To answer your question, I would assume most colorless oils are delta 8 THC unless you have evidence otherwise. A long time user of our equipment (https://www.instagram.com/dabtown/?hl=en) does have some work into the colorless delta 9.

      -Luke

  • Question difference between delta 8 and delta 9. Those delta 8 come from thc flower or hemp flower..

    • Delta 8 is only is the plant in really really small amounts. It can come from D9 THC or CBD. D9 THC is probably the intermediate form that the CBD goes through on the way to D8.

      To answer your question, it can come from either form of the plant, but cheap and “legal” D8 and on the market right now is coming from CBD exclusively.

  • Quick question, I’m looking up the tendency of distillate to ‘go bad’ and telltale signs of it because i found a sample that has a cloudy white haze at one of its ends, similar to a clarified butter. Thought it could be mold but havent seen this before so was eager to verify this could happen after handling and transferring containers?

    • Hi,

      Your description of looking like clarified butter does make me think of distillate that has not been fully winterized. 3 big components (and there are others) that can indicate the quality of distillate are color, clarity, and consistency. If the clarity is off, that is generally a winterization problem.

      However, your description of it “sinking” makes me think that it could be caused vacuum grease contamination. It does not dissolve in distillate at all, but it can thin out with the distillate when warmed. I have seen many labs have an issue with grease leaking through joints and making it into the product stream.

      Warm a small sample of distillate and dissolve it in grain alcohol with a ratio of 5:1 ethanol to distillate. Anything lower proof won’t work, but higher proof is fine. Waxes will at least partially dissolve. They also have a tendency to either float or settle out over time. Vacuum grease will not dissolve.

      -Luke

  • I’m having an issue with my liter of distillate having color separation at the very top. I’ve got a nice golden light gold and about a 1/2 inch on top has turned darker. Not black just a darker color than the golden underneath it. If I was sold a Delta 8 in Delta 9 blend would this happened? What could be causing the color separation? Again I have a 1/2 in of darker colored Amber on top of a whole bunch of nice gold.. I’m using a heating pad to warm up my liter before cooking with it. I had somebody say that it may be the way that I’m heating it but why would it end up with a dark layer on top? I can email pictures to anybody that might have an answer

    • Hello,

      To me that sounds like oxidation of just the top layer of your oil. The oxidation is often pink/red/brown and creeps down in a ring around the top and down the sides of the jar. If it is a gradient creeping down, I would bet it is just oxidation.

      D8/D9 blend probably wouldn’t be the cause because I have seen this situation happen with “pure” both. Not to say it couldn’t be cut.

      Heating can cause color change definitely. Just try to keep the amount of heat and the time it is being heated to a minimum. If you ever see it smoke a little, you should remove from heat immediately.

      To prevent the oxidation:

      1) leave as little space at the top of the container as possible
      2) vacuum seal if in a mason jar or backfill with an inert gas
      3) store away from lights

      -Luke

  • […] out for when using Delta 8 vapes. If the liquid is a darker color, then it is likely that it has begun to oxidize. This means that the liquid is starting to go bad and its effects are not going to be as potent as […]

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