Trichome color and THC

Hi Guys,

I just found this pdf online (http://www.gwpharm.com/uploads/finalfullthesisdjpotter.pdf). It’s a thesis on Cannabis botany, and it has some really great info in it. I haven’t read the whole thing yet, but I did read one section on trichomes. The author does a study on trichome color and THC/CBN concentrations. Conventional wisdom says that trichomes come in 3 colors: clear, cloudy and amber. Also, that harvesting for peak THC should be done when the trichs are cloudy. If they turn amber it means that the THC is degrading into CBN, and potency will be reduced. Also, harvesting when the trichs are darker gives more of a couchlock effect, whereas harvesting when clear gives a racy head high. I’ve been interested in finding real data on THC content as a function of trichome color, and now I’ve found it!

The author defines a scale from 1 to 9 where 1 is clear and 9 is very dark.



He then subjects the specimens to THC analysis by gas chromatograph, and plots the data. The x axis shows increasing trichome darkness (1-9) and the numbers beneath are the number of specimens measured.




As you can see, the samples labeled 1-8 show very little variation in THC content. It’s not until the darkest trichomes (level 9) that you see a drop in THC, and that is measured from a single specimen. The rest of the specimens are very similar, and vary between 12-16% THC.


He then measured CBN, the breakdown product of THC.




Here we see that CBN content trends upwards slightly in darker trichomes, but really constitutes only 0.5 to 1.5% of the cannabinoid content. I think this is probably a negligible amount, being only one tenth the amount of THC.


Overall, I think this makes a good case that the harvest window is wider than one might think. Harvesting when the trichs are amber shouldn’t make a big difference, unless you let them go way long and harvest when very dark. CBN itself isn’t dark, and it’s not known why they darken. But the take home message is that dark trichs don’t necessarily mean that the plant is past it’s peak potency.


There’s lots more great info in the entire thesis, so read it if you’re interested in these things. I’ll be poring over it myself.

Cheers,

bblunt

Good resource but I entirely disagree with your conclusions.

bblunt said:

I think this is probably a negligible amount, being only one tenth the amount of THC.

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10% of the total amount of THC is far from negligible.

bblunt said:

As you can see, the samples labeled 1-8 show very little variation in THC content. It’s not until the darkest trichomes (level 9) that you see a drop in THC, and that is measured from a single specimen.

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Are we even looking at the same chart? What the graph shows is what the expert on the matter, some professor, as outlined in an article by Mel Frank in Hightimes years ago, and that's that not amber, not cloudy, but peak potency (THC-wise anyway) is before they turn cloudy (what above is called misty white for some reason...).

bblunt said:

Overall, I think this makes a good case that the harvest window is wider than one might think. Harvesting when the trichs are amber shouldn’t make a big difference, unless you let them go way long and harvest when very dark.

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A drop from 16.3 to 12-14 IS a big difference. Maybe not if you have a couple of plants at home, but man, your conclusion is the opposite of what it should be. The harvest window is not at all wider than one might think.

bblunt said:

As you can see, the samples labeled 1-8 show very little variation in THC content.

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Are you reading the thesis in braille? If so, you're not holding the graph horizontally or something.

bblunt said:

But the take home message is that dark trichs don’t necessarily mean that the plant is past it’s peak potency.

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I'm genuinely baffled by that statement.

Sativied said:

Good resource but I entirely disagree with your conclusions.

10% of the total amount of THC is far from negligible.

Are we even looking at the same chart? What the graph shows is what the expert on the matter, some professor, as outlined in an article by Mel Frank in Hightimes years ago, and that's that not amber, not cloudy, but peak potency (THC-wise anyway) is before they turn cloudy (what above is called misty white for some reason...).


A drop from 16.3 to 12-14 IS a big difference. Maybe not if you have a couple of plants at home, but man, your conclusion is the opposite of what it should be. The harvest window is not at all wider than one might think.

Are you reading the thesis in braille? If so, you're not holding the graph horizontally or something.

I'm genuinely baffled by that statement.

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I was typing when Sativied posted, and I agree with him.

bblunt said:

Hi Guys,

I just found this pdf online (http://www.gwpharm.com
View attachment 3276539


As you can see, the samples labeled 1-8 show very little variation in THC content. It’s not until the darkest trichomes (level 9) that you see a drop in THC, and that is measured from a single specimen. The rest of the specimens are very similar, and vary between 12-16% THC.

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A drop in percent from 16-12% is not negligeble. It may be only 4%, but when the max of the sample was only 16%, that's 25% gone.

The graph says peak potency is from 4-6, opaque white, slightly brown, or light brown. Meaning you wouldn't want to harvest before or after that point if possible.

Hi everyone...thanks for the replies. Let me address your concerns here:

10% of the total amount of THC is far from negligible.

That 10% CBN figure is a very generous estimate, based upon the majority of trichs being mid to dark, and coming from 20 and 6 measurements respectively. The error bars on those plots are pretty wide, indicating poor accuracy in that measurement. If you assume that THC is breaking down into CBN, then there's no agreement between the THC chart and the CBN chart, as the THC does not drop 10%. The THC level is flat with dark trichs.

Are we even looking at the same chart? What the graph shows is what the expert on the matter, some professor, as outlined in an article by Mel Frank in Hightimes years ago, and that's that not amber, not cloudy, but peak potency (THC-wise anyway) is before they turn cloudy (what above is called misty white for some reason...).

On the THC chart, the highest value is from clear trichs. Again, this is based upon 8 measurements, and the error bars are relatively wide. It may be that clear trichs have the most THC, but I'd like to see more data. Also, the conventional wisdom on this site (and most others) is that cloudy trichs represent peak potency, and amber trichs indicate loss of potency. I think this is not supported by the data presented.


A drop from 16.3 to 12-14 IS a big difference. Maybe not if you have a couple of plants at home, but man, your conclusion is the opposite of what it should be. The harvest window is not at all wider than one might think.

Saying that the potency drops from 16% to 12% based upon this graph is a bit cavalier. If you ignore the values for 1 and 9 (based upon 8 and 1 measurements, respectively) the error bars for the remaining measurements overlap, except for number 4. Even in that case, the difference is about 1%, and even if that's accurate I don't believe I could tell the difference between 15 and 16% THC. Between 2 and 8, the graph is essentially flat. This is not the pattern I would expect to see if the conventional wisdom about trich color and peak potency were true.

Are you reading the thesis in braille? If so, you're not holding the graph horizontally or something.

I hold a PhD in molecular biology. Looking at and interpreting data in the biological sciences is something
I do every day. The slope of the regression line is negative, and statistically significant, but the correlation is weak, based upon the R^2 value.

I'm genuinely baffled by that statement.

Hope this explanation helps!

bblunt

bblunt said:

That 10% CBN figure is a very generous estimate, based upon the majority of trichs being mid to dark, and coming from 20 and 6 measurements respectively. The error bars on those plots are pretty wide, indicating poor accuracy in that measurement.

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I'm talking about the THC, which I quoted. Surely a PhD can figure out the quote feature. So... now that your conclusion is questioned the data is not accurate enough? Regardless, not a great argument. 5% would still be still significant. It would be silly to expect a huge difference within the relatively large (to the entire flower period) harvest time frame.

bblunt said:

On the THC chart, the highest value is from clear trichs. Again, this is based upon 8 measurements, and the error bars are relatively wide. It may be that clear trichs have the most THC, but I'd like to see more data.

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Yes the error bars are relatively wide... 15-18% for clear. Let's just assume the data we're discussing is what is and its accuracy doesn't adapt to your conclusion. The graph clearly show clear is peak. You cannot get 4+5 only on a bud without getting darker ones as wel, and without obviously losing more clear.

bblunt said:

Also, the conventional wisdom on this site (and most others) is that cloudy trichs represent peak potency, and amber trichs indicate loss of potency. I think this is not supported by the data presented.

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The more dark (lower THC in graph) trichs, the less clear trichs (higher THC in graph)... It's a little more specific in practice than what you claim is conventional wisdom. You can't place an entire plant on just one point on the graph and capture that point when you chop the plant.

He "visually assessed" the color and created 9 levels. Growers aren't going to do that.

1 is clear, 2-4 is cloudy, 5-9 is amber/brown.

The graph shows any practical combination of the first 4 (cloudy+clear, little amber is ok) results in higher THC% than any practical combination that includes more of the last 5. More of 6 automatically means less from 1-5.

bblunt said:

Saying that the potency drops from 16% to 12% based upon this graph is a bit cavalier. If you ignore the values for 1 and 9 (based upon 8 and 1 measurements, respectively) the error bars for the remaining measurements overlap, except for number 4. Even in that case, the difference is about 1%, and even if that's accurate I don't believe I could tell the difference between 15 and 16%

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Except for number 4... which we're just going to imagine isn't there? Again, this is where you went wrong already and no irrelevant attempt to gain credibility is going to change that that 4% "you" mentioned earlier" is not "very similar". It's as if you think you can selectively and subjectively pick when you choose the low or the high end of the error bars but even then 1% isn't as little as you think it is. Well, again, maybe if you have a couple of plants at home. On a total of 15% that 1% is nearly 7% of the total THC contents. If you think that is negligible, for let's say concentrate makers..., then you shouldn't be concerned about this in the first place and you're probably better of reading something else.

So the take home message is (if max THC is the goal): Avoid the brown ones (and no, that's not an Uncle Ben quote)

Sativied said:

I'm talking about the THC, which I quoted. Surely a PhD can figure out the quote feature.

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Zing! Here's me using the quote feature. Can I have my degree back?

I assumed you were talking about the equilibrium between THC and it's conversion into CBN, which was my original point. I'll reiterate it now: If one assumes that THC breaks down into CBN, then the data show that the amount of CBN in brown trichs is very low. This does not support the idea that amber trichs lose potency due to conversion of THC into CBN.

Sativied said:

So... now that your conclusion is questioned the data is not accurate enough?

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That's right. The error bars are wider than you mother's knees on Friday night. I mean, just look at the graph. Just look with your eyes.

Sativied said:

Yes the error bars are relatively wide...

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I accept your apology.

Sativied said:

Let's just assume the data we're discussing is what is and its accuracy doesn't adapt to your conclusion.

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That's exactly what I'm doing. I'm not adapting the data to my conclusion. You're adapting the data to your conclusion. I'm looking at the data in context, with the understanding of what error and accuracy mean. Should I look at category 9, with one measurement, and discuss what it is, or discuss the fact that it's an unreliable measurement? Should I give it the same weight at a category with greater than 50 measurements? Listen to yourself. You sound like a retard.

Sativied said:

The graph clearly show clear is peak.

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Again, fucking retarded. Get a clue. Start with understanding what error is, and then you can join the adult conversation.

Sativied said:

You can't place an entire plant on just one point on the graph and capture that point when you chop the plant.

He "visually assessed" the color and created 9 levels. Growers aren't going to do that.

1 is clear, 2-4 is cloudy, 5-9 is amber/brown.

The graph shows any practical combination of the first 4 (cloudy+clear, little amber is ok) results in higher THC% than any practical combination that includes more of the last 5. More of 6 automatically means less from 1-5.

Click to expand...

None of this is relevant to my point. I'm not claiming anything like what you're stating here. Do you like arguing with yourself? Is it because it's so easy to win?

Sativied said:

Except for number 4... which we're just going to imagine isn't there? Again, this is where you went wrong already and no irrelevant attempt to gain credibility is going to change that that 4% "you" mentioned earlier" is not "very similar". It's as if you think you can selectively and subjectively pick when you choose the low or the high end of the error bars but even then 1% isn't as little as you think it is. Well, again, maybe if you have a couple of plants at home. On a total of 15% that 1% is nearly 7% of the total THC contents. If you think that is negligible, for let's say concentrate makers..., then you shouldn't be concerned about this in the first place and you're probably better of reading something else.

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So, is condition 4 accurate? Well, there are 52 measurements there, and the error bars are narrow. But to me it seems like a fairly weak data point to conclude that it represents peak potency. If different labs were to repeat this experiment, would the graph flatten out? Would the peak become more pronounced? I don't know. But I'm not going to give it more weight than it deserves. My point, which I'll reiterate again, because you seem insistent on arguing on a different point, is that potency, as measured by THC concentration, does not decline when the trichs turn amber. It doesn't. If you have data that shows different, please post it. I'm willing to see and accept it if it's good data. You are not. You're trying to seem like you know what you're talking about when you clearly do not. I'm trying to figure out the truth here, and you are not.

Sativied said:

So the take home message is (if max THC is the goal): Avoid the brown ones (and no, that's not an Uncle Ben quote)

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Who cares what Uncle Ben says? I don't. I don't care what you say either. Facts are facts. You don't have to accept them, but pissing all over facts doesn't really get you anywhere, does it? But I'll take it one step further. Can we agree that, according to you, the later you harvest the less potency will be? I have three white widow clones going now, and I will harvest one when mostly clear, another when mostly cloudy, and another when significantly amber. I will then test the potency of each. I can't measure the THC, but then again I don't grow in order to get a number. If the clear or cloudy is significantly more potent than the amber, I'll post here saying that you were right all along. And if you want, please do the same. Test it for yourself. Don't listen to me, listen to facts.

I find the sample size a little disturbing. Only 1 example on the 9 scale?

THC can be converted to CBD because of time (storage) or smoking.

Some of you may find this helpful:

http://biocyc.org/META/NEW-IMAGE?type=PATHWAY&object=PWY-5140&detail-level=4&detail-level=3&detail-level=2

Also of note to add to the original PDF discussion - there are 3 types of trichs and only 1 type (Capitate Stalked) is being measured in that study.