Several years ago I conducted a fun little experiment while looking for the ideal times and temperatures for using a kitchen oven to decarboxyilate cannabis. This turned into the popular article “Decarboxylating Cannabis: Turning THCA into THC”. The process worked great but many readers had questions. What better than a follow up article to add clarity and improve upon the process. For those still trying to figure out what decarboxylating means, go read the original article first, you’re slowing down the class.
Two Problems With The Kitchen Oven Decarb Method
First, standard household ovens don’t let you dial in very exact temperatures. Sure you can set the temperature wherever you want, but oven temperatures tend to fluctuate, which means you are really only setting the average temperature. For baking a pie this is just fine, but we have to be a little concerned with temperature spikes vaporizing the very cannabinoid we are trying to tinker with. The boiling point of THC is 314.6°F but many other potentially medicinal compounds in cannabis can be lost at lower temperatures. Standing by the oven checking the thermometer every few minutes pretty much sucks.
The second problem is odor. Personally, I don’t mind the aroma of slowly roasting cannabis wafting from my kitchen. It has been brought to my attention that some of you need to be a bit more discreet. Lets just say decarboxylating cannabis in the kitchen oven won’t go unnoticed by the delivery man.
Spark of Genius
Let’s be honest, neither of these are good reasons to create whole new method of cooking. Luckily someone did it for me. In walks Sir Benjamin Thompson the Count of Rumford. Round of applause. Now let’s continue. In 1799 he discovered the cooking method now referred to by the Frenchies as Sous-Vide, meaning “under vacuum”.
This is a method which uses an airtight plastic bag in a water bath or in a temperature-controlled steam environment at lower temperatures for longer than normal cooking times. The intention is to cook the item evenly, ensuring that the inside is properly cooked without overcooking the outside, all while retaining moisture. Imagine a New York steak cooked a perfect medium rare all the way through. What could be better? How about a method for decarboxylating cannabis that doesn’t require watching your oven like a hawk or skunking up your house.
Thinking “par Dieu” the French might be on to something, I bought myself an Anova precision sous vide immersion circulator and cooked up a delicious organic ribeye. Calm yourself ladies, I don’t really speak French but with the help of the Anova, I do cook a mean steak. It’s ability to decarboxylate cannabis was still in question, so I devised the following experiment.
Decarboxylating cannabis in the oven didn’t require much in the way of gadgetry. For those of you always looking for an excuse to go shopping, this method is going to be a real treat. Here is what I used for this experiment. Feel free to substitute as needed.
- 12 quart stock pot. I bought a Denmark because it’s made in China – $44
- Anova Sous Vide Immersion Circulator. The red one matches my KitchenAid – $199
- Food Saver Vacuum Sealing System – $79
- Escali Aqua Digital Liquid Measure Scale -$49
- Cuisinart Coffee Grinder – $30
Trim, bud, kief, bubble hash or hash oil should all work just fine for this method. For this experiment I used about 6 grams of bud donated by Club Pitbull in Salem Oregon. If you are in the Salem area in need of a great dispensary, definitely check them out. Thanks fellas!
Let The Decarboxylating Begin
If you are using bud or trim like I am, the first step is to grind it up. A rice size grind should be sufficient. I used my coffee grinder which was pretty caked with kief by the time I was done. I tried to scrape it off and back into the bud with marginal success. My coffee had a little extra kick for the next few days. I divided the ground bud into three samples, each about 2 grams in size.
The first sample I sealed it in its own bag. We will call this sample 1, and it is the control for the experiment. It was not exposed to any heat other that what it may have encountered before it came into my possession.
The next two sample would be sealed in a separate bag and submerged in the hot water to hopefully decarboxylate. I wanted some ballast for this bag so one end would sink to the bottom of the pot and the other end would float suspending the two samples in the middle of the pot of hot water. I sealed two butter knives into the bottom of a foodsaver bag with a seal above and below the knives so that they would not come in contact with either sample of bud. This may not have been necessary but it worked great.
Above the sealed butter knives I added 2 grams of ground bud and sealed the bag again above the bud. This would be sample 3 for the test. Essentially I created multiple sealed compartments to separate the samples and the butter knives while still using only one vacuum seal bag. I added a second seal about a half inch above the first sea because I wanted to later cut the two bud compartments apart without actually opening them. Last I added the remaining 2 grams (sample 2) of ground bud and made a final seal above the sample.
To help the Anova bring the water to temperature I started with the hottest tap water my sink could produce, about 120°F. Placing the Anova in the water, I secured it to the side of the pot with the screw clamp. The plan was to mimic the time and temperature of the oven decarb experiment, but the maximum temperature on the Anova is 210°F. Not wanting to max it out and potentially break it on the first run I settled on 200°F and increased the time for the experiment.
I decided on 1 hour for sample 2 and 1 hour 40 minutes for sample 3. Why 1:40 you ask? I considered 2 hours for the sample 3 but I had a hunch it really wouldn’t need that much time. Once the water reach 200° F I lowered the bag containing the two butter knives and cannabis sample 2 and 3 into the hot water.
After 1 hour I extracted the samples and cut between the two seals removing sample 2 from the top of the bag. I placed the remainder of the bag containing sample 3 and the butter knives back in the pot and hopped in the shower. I removed sample 3 at 1 hour 40 minutes and cut it free from the butter knives.
Lab Test Results
Rose City Laboratory agreed to help us out with our experiment by donating their lab testing services. These guys are awesome, really easy to work with, and would absolutely recommend them.
I received the lab results of the liquid chromatography testing by email within 24 hours of dropping off the samples. Here are the results from the testing:”
- Sample 1 was not decarbed at all, just ground up and sealed in the bag.
- Sample 2 was submerged in the 200°F water for 1 hours.
- Sample 3 was submerged in 200°F water for 1 hour 40 minutes.
Here are the results from the testing:
|Cannabinoids||#1 (no decarb)||#2 (1 hour decarb)||#3 (1:40 decarb)|
|Total THC Adjusted**||14.14%||10.31%||9.78%|
*Total THC = (THCA x .877 + THC) because THCA weighs about 12.3% more than THC so the percent of THCA multiplied by .887 should equal the amount of THC after decarbing.
**If you want accurate data, lab test readings for cannabinoids should always be adjusted to compensate for the quantity of water found in the sample. In this case a water content of 10% was used for the baseline. If this just blew your noggin, here is an article on how and why cannabis lab results are often misleading because of water content.
What Does It All Mean?
Though sample 1 was our control and not exposed to the hot water bath, the lab results show that it was already about 24% decarboxylated. This means that the starting point for samples 2 and 3 was also about 24% decarboxylated. This could be because it was an older sample or had been exposed to some heat before it was given to me. No big deal.
Sample 2 shows that after 1 hour at 200°F the cannabis was 86% decarboxylated. Pretty good but not quite finished. This may be a good stopping point for those who want to leave some THCA and take advantages of it’s own medicinal qualities.
Sample 3 at 1 hour and 40 minutes was 100% decarboxylated. It appears this would to be a sufficient time and temperature to decarboxylate cannabis with the sous-vide method. Further experiments could reduce this time but batch size, density and starting THC level could also require adjustments. Unless you are going to have your batch lab tested I would not cut down the time or temperature.
The results of this experiment indicate we may have lost some THC during the decarboxylating process. It’s also possible that the samples were not exactly the same to begin with. It’s always difficult to get the exact same samples when working with flowers. Even though all three samples came from the same blend, one of the sample could have had some of the kief that separated out in the coffee grinder while the others did not. Using only kief in the experiment would have made it much easier to have nearly identical samples.
It might be interesting to see if the THC levels continued to drop if a sample was left in the heated water beyond the 1 hour 40 minutes needed for 100% decarboxylation. If so, one would want to keep the decarb time to the minimum required to complete the process. Keep an eye out for an experiment along these lines down the road.
I hope my little experiment on sous-vide decarboxylating cannabis has been informative and helpful. I still don’t know if this is the ideal way to turn THCA into THC but it does have some real advantages over the kitchen oven decarboxylating method. As always, ask questions in the comments below and please feel free to chime in if you have some insights or knowledge on the subject that may help us improve the process.
Decarboxylation: Marijuana Alchemy,