How do different storage conditions affect Max THC?

Years ago, I placed a friend’s bag of weed in direct sunlight. He quickly grabbed it and moved it into the shade, saying that the weed would go bad if it was kept in sunlight.

Having the instruments to run almost any cannabis tests we can think of at MCR Labs, we decided to test this myth.

So we set out to answer the question: How do different storage conditions alter Max THC, or the maximum theoretical THC,  in cannabis after 50 days?

First, we tested a Blue Dream flower to get the baseline Max THC. Here are the results:
THC:  0.4%            THCa:  23.9%            Max THC: 21.3%
*Max THC = (87.7% x THCa) + THC

Then we split up the same Blue Dream flower and placed it into 4 different glass containers:
Container One was left open, and placed in the shade
Container Two was closed, and placed in the fridge
Container Three was closed, and placed on a windowsill, in direct sunlight
Container Four was closed, and placed in the shade


After 50 days, we tested the Blue Dream flower from each container. The following graph shows the remaining Max THC in each storage condition.

cannabis storage graph 2

The full numbers:cannabis storage table 3


Regardless of storage conditions, all flower samples lost a significant amount of Max THC.  However, the flower that was on the windowsill lost 30% more Max THC than the flower that was kept in the fridge.  So there you have it. 

Full cannabinoids profiles can be found here. This experiment was performed only one time, using one flower. We will continue this line of tests, and will repeat this experiment with a large sample size in the future.


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  1. Jeans available 06/24/2016, 2:41 am Reply

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  2. Cantech 07/11/2016, 6:14 am Reply

    Great information! Proof that making concentrates with fresh material is so important. Lesson learned. Thank you.

    P.S. It would be great if you could test the terpene content with a similar method and post the results. =)

  3. Cantech 07/18/2016, 9:04 pm Reply

    Hello, this is great information. It would be great if you could do the same test on terpenes.

    I really love that you’re sharing actual research data rather than hearsay that is found on the rest of the internet. Thank you.

  4. [hydrocarbon] 11/03/2016, 5:22 am Reply

    Great post. I would be interested in a similar experiment measuring the different storage conditions’ effects on terpene content and/or degradation. Due to the entourage effect it makes the most sense that cannabis with a more intact terpene profile would be of greater benefit than without it.

    It would be particularly interesting to see which terpenes in particular are more likely to be lost. The spice cabinet comes to mind when thinking about terpenes – many spices that share a terpene with cannabis do retain at least a significant portion of that terpene, otherwise they would not remain highly aromatic throughout dry storage. However, given the varying volatility of terpenes present in cannabis, it’s not unimaginable that there are one or two present that degrade more rapidly than the rest. One theoretical use for this information is the preservation of more volatile terpene profiles for longer periods of time, i.e. by infusion of fresh flower into a cooking oil/alcohol/glycerin.

    For example, alpha-pinene has a vapor pressure almost 30 times that of linalool. This leads me to speculate that strains heavy in linalool will store better than those heavy in pinene. I could be wrong as my understanding of volatility is elementary but if I’m correct then strains such as SSH/Jack/OGK may demand more urgent consumption/infusion than, say, Blueberry or a descendant thereof. Could be good to know for sure for those who sit on their buds for longer periods of time (I’m sure within the 50 day window you used there would be a quite considerable difference).

    If somehow you found the time to try something like this it would be invaluable – there is only so much speculation one can do on PubChem. Cheers.

  5. jarrod m womble 11/17/2016, 12:12 pm Reply

    Re:the flower that was on the windowsill lost 30% more Max THC than the flower that was kept in the fridge

    This is a bit misleading. Since the values in question are already expressed as a percentage there is no need to perform a “double conversion” which ultimately skews the reported data by a factor of 10 😉
    The difference between 16.3% Max THC (fridge) and 14.7% THC (windowsill) is actually 1.6% which may be within the limits of the analytical variability of the method employed.

  6. Some Dude 11/24/2016, 11:55 am Reply

    This doesn’t really tell much of anything. you should have done a sample that was left open, and in direct sunlight. We know both air and light degrade thc, but to what point both of them do that, would be nice to know.

  7. Mike 04/07/2017, 8:22 am Reply

    What about freezer storage? Would love to see the data on that as well.

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