Post-Harvest Trichomes and Light

Azimuth

Azimuth

Well-Known Member
3 Member of the Month
October 2024
We hear the admonition all the time about drying and curing your bud out of the light but I'm wondering if there is any real science to this.

Or, more specifically, does the intensity of the light matter? I get that strong sunlight or even grow lights could negatively impact trichomes as I have seen the bleaching effect both sun and grow lights can have on containers, but I'm wondering if ambient light would have any material impact at all?

I know microbes are said to not like light, and we are using them to help cure, so maybe that's it?
 
no science to back me up but I’d say absolutely indoor light intensity matters on trichs after the chop, think some ambient is ok but I’m sure most of us prefer minimal exposure for a reason

many other crops are kept in low light / near dark conditions post harvest, aromatics like tobacco and spices, also fruits and veggies unless they need to ripen further. But consider too years ago tobacco was cut, shocked and bound up teepee style right in the open field to dry in the sun & rain for the first month or two before going to the barn

thanks Azi, as always I’m interested to see where thread this leads
 
Regarding the intensity of light, it does matter. The stronger the light, the more quickly it can cause degradation. However, even ambient light can cause degradation over time, so it’s always recommended to cure and store cannabis in a dark place.

As for the role of microbes in curing, it’s not the main reason for avoiding light, but it could be a factor. The curing process is anaerobic (occurs in the absence of oxygen) and some beneficial microbes involved in this process may be photosensitive, meaning they function less optimally in the presence of light.
 
There has been work done on the effects of sunlight
Azimuth said:
We hear the admonition all the time about drying and curing your bud out of the light but I'm wondering if there is any real science to this.

Or, more specifically, does the intensity of the light matter? I get that strong sunlight or even grow lights could negatively impact trichomes as I have seen the bleaching effect both sun and grow lights can have on containers, but I'm wondering if ambient light would have any material impact at all?

I know microbes are said to not like light, and we are using them to help cure, so maybe that's it?
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yes, intensity and wavelength have a lot to do with it. All direct light will degrade THC, but the more ionizing the wavelength (UV) the more quickly THC is degraded. No direct light is what you want. I doubt reflected light causes much harm, but should still be avoided when possible.
 
Azimuth said:
We hear the admonition all the time about drying and curing your bud out of the light but I'm wondering if there is any real science to this.

Or, more specifically, does the intensity of the light matter? I get that strong sunlight or even grow lights could negatively impact trichomes as I have seen the bleaching effect both sun and grow lights can have on containers, but I'm wondering if ambient light would have any material impact at all?

I know microbes are said to not like light, and we are using them to help cure, so maybe that's it?
Click to expand...
Plants tissues will dry out to faster with added light during drying since darkness slows down the metabolic rate. It's not "dead" hanging on the drying rack and there's a lot of processes still going on in the plants tissues during drying. Most people aim to preserve terpenes and flavour, then you ideally want them to dry as slow as possible.

Cheers!
 
Azimuth said:
We hear the admonition all the time about drying and curing your bud out of the light but I'm wondering if there is any real science to this.

Or, more specifically, does the intensity of the light matter? I get that strong sunlight or even grow lights could negatively impact trichomes as I have seen the bleaching effect both sun and grow lights can have on containers, but I'm wondering if ambient light would have any material impact at all?

I know microbes are said to not like light, and we are using them to help cure, so maybe that's it?
Click to expand...
This video might be of interest but there's no mention of light levels. I did find it interesting to hear about the difference between cannabis that's been grown outdoors vs indoors. Also, the inability to quantify a difference between a short cure vs a long cure.

RE. light having an impact, this info leads me to think that you can reduce THC but you've got to really work at it.

My take is that we don't need to do "night ops" to harvest and dry but don't do it in the sunlight. I've dry trimmed a few grows and I just leave them hanging in my windowless garage.
 
I just skimmed this paper and this phrase jumped out at me -

"Trofin et al. [127,128,129] have extensively investigated the stability of various cannabis products, focusing on major cannabinoids via kinetic models and in-vitro studies, and have found that the storage of cannabis at 22 °C with the presence of light is highly detrimental to cannabis compared to samples stored in darkness at 4 °C."
 
Just made a discovery. I have 1 gallon ziplock bags that I was going to turn into hash a month ago and forgot about. They have been sitting on a corner table with a 45wat equivalent LED lamp 16 inches away this whole time. I can pull out a bud from the top tonight and let you know if it effected it in any way. Purely in the name of science!
 
Sativa1970 said:
Just made a discovery. I have 1 gallon ziplock bags that I was going to turn into hash a month ago and forgot about. They have been sitting on a corner table with a 45wat equivalent LED lamp 16 inches away this whole time. I can pull out a bud from the top tonight and let you know if it effected it in any way. Purely in the name of science!
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:)"Purely in the name of science!" Why, of course. We would expect no less;). It is a sacrifice on your part.
 
013 said:
no science to back me up but I’d say absolutely indoor light intensity matters on trichs after the chop, think some ambient is ok but I’m sure most of us prefer minimal exposure for a reason
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Thanks 13. Yeah, that's how I'm leaning, but I always like to know the why's behind our practices. Is it just bro science or is there actually something to it.

Cultiuana said:
Regarding the intensity of light, it does matter. The stronger the light, the more quickly it can cause degradation. However, even ambient light can cause degradation over time, so it’s always recommended to cure and store cannabis in a dark place.
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Thanks, Cult. I plan to keep the harvest "mostly" out of direct light light, and also mostly out of light at all, but probably won't be fanatical about it.

Phytoplankton said:
yes, intensity and wavelength have a lot to do with it. All direct light will degrade THC, but the more ionizing the wavelength (UV) the more quickly THC is degraded. No direct light is what you want. I doubt reflected light causes much harm, but should still be avoided when possible.
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Thanks, Phyto. Certainly no direct sunlight is the plan, but I'm not building a darkroom! :laughtwo:

Wastei said:
Plants tissues will dry out to faster with added light during drying since darkness slows down the metabolic rate. It's not "dead" hanging on the drying rack and there's a lot of processes still going on in the plants tissues during drying. Most people aim to preserve terpenes and flavour, then you ideally want them to dry as slow as possible.
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Thanks Wastei. I've long thought the plant was still clinging to life for a couple of days after the harvest at least. We see that with clones all the time. They hang on until they can grow so roots to replace the amputation we did.

A slow dry is the goal. Well, more like a fast dry down to about 70% and then string it out from there.

Delps8 said:
My take is that we don't need to do "night ops" to harvest and dry but don't do it in the sunlight. I've dry trimmed a few grows and I just leave them hanging in my windowless garage.
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🤣 Ha! Thanks Delps. Yeah, I'm not going to tie myself in knots over it. Reasonable care is the standard. Reasonable being the operative word.

Delps8 said:
"Trofin et al. [127,128,129] have extensively investigated the stability of various cannabis products, focusing on major cannabinoids via kinetic models and in-vitro studies, and have found that the storage of cannabis at 22 °C with the presence of light is highly detrimental to cannabis compared to samples stored in darkness at 4 °C."
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Two different variables so how does one know if it was the light or the temperature that was most responsible? It would be more helpful if they ran it all four ways, light, no light, and 22 vs 4 against each other. Then we'd have some useful data!

Sativa1970 said:
The only light that catalase the decomposition reaction is UV. The rest of the spectrum is too low energy to effect cannabinoids and bacteria. Standard indoor lighting won't effect it unless you are trying to dry under a grow light or the light of an easy bake oven.
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The Easy Bake Oven is only used for chocolate chip cookies. The toaster oven on the other hand....

Sativa1970 said:
Just made a discovery. I have 1 gallon ziplock bags that I was going to turn into hash a month ago and forgot about. They have been sitting on a corner table with a 45wat equivalent LED lamp 16 inches away this whole time. I can pull out a bud from the top tonight and let you know if it effected it in any way. Purely in the name of science!
Click to expand...
We appreciate you taking one for the team! Thanks Sativa!
 
Sativa1970 said:
Results are in! I was in no condition to type after 2 hits so I would say that light had no effect on the potency. Flavor was the same. Wife says new house rule. No more decreeing "In the name of science!" while she is trying to cook. Swedish meatballs downgraded to sandwiches within 10 minutes.
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Nice! Thanks for sharing. You doing the cooking or did she participate in the experiment as well? :laughtwo:
 
Azimuth said:
Nice! Thanks for sharing. You doing the cooking or did she participate in the experiment as well? :laughtwo:
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She was cooking when I walked into the kitchen with the bong. Told her it should be less potent than normal. When she set a plate with a sandwich in front of me I flashed back to the commercial "This is your brain, this is your brain on drugs".
 
Hey Azi,

I found an interesting study done by Anresco Labs in 2022, where they stored trim in clear or amber jars, and at three different temperatures... (emphasis/annotation added)...

"Temperature strongly influenced the degradation of THCA to Δ9-THC, yet that did not materialize into statistically significant deviations in total potential THC through 90 days.... After 90 days, Δ9-THC degraded into CBN at a significantly higher rate in samples held at higher temperatures. In the final 3 testing periods, samples held at 4°C [39°F] retained an average of 3.2% more total potential THC than samples held at 20°C [68°F], and 14.1% more total potential THC than samples held at 30°C [86°F].​
​
[re: the effect of light...] Samples held in amber jars marginally reduced the rate of degradation of THCA to Δ9-THC, as well as the degradation of Δ9-THC to CBN. By day 360, samples held in amber jars retained 2.56% higher total potential THC than those held in clear jars.​
​
Time was the most significant driver of potency degradation. By day 30, total potential THC decreased by an average of 11.83%, and by day 60 degradation of total potential THC exceeded 12.5% for every temperature and container condition...."​

In the charts below, from the Anresco study, you can see that degradation increases after the 90-day mark, whether stored in amber or clear, and for storage temps 68 F and 86 F. (There's something magic about 90 days.) Storage temp 39 F actually gets a bump after 90 days (blue line), for both amber and clear. Strangely, the trim stored at 86 F in amber does the best up to 90 days (orange line)! According to this, the best way to store buds up to 90 days is in amber jars at room temp. After 90 days, it's best to refrigerate. Since drying/curing happens typically within the first 60 days, and considering the preservation of terpenes, the best temp is probably 64 F, and in total darkness. Here's Ed Rosenthal's fine points on drying and curing: HERE.

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(Potential THC is calculated using the formula: Total THC = (0.877 * THCA) + Δ9-THC.)

:tommy:
 
THCA to delta 9 is a restructuring exchange formula of the the same elements with no loss or gain. Delta9( C22 H30 O4) has a reaction product of CBN(C21 H26 O2) and ( C1 H4 O2). The byproduct C1H3O2 can only be formed from an oxidation reaction therefore requiring an external source of available O2. It then decomposes into 2CO2 and 2H2O over time. Increasing available O2. Jarring before the chlorophyll was done decomposing and gassing off CO2 would also increase O2 over time. Temperature is the catalyst for the decomposition reactions releasing O2 and high O2 enables the oxidation of delta 9 into CBN. That could possibly explain the 90 day anomaly.

That's why I vacuum seal all my jars before storage. Popped open a 6 year old jar yesterday.
 
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