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Cannabis Decarboxylation

Radagast97

New Member
Mitchell's link on decarboxylation of THCA is excellent, but a number of people might be a bit intimidated by the degree of science and chemistry in the paper so I thought I'd do my best to convert it into English. If I slip into the nerd zone, accept my apologies now.

THC and CBD are the primary bioactive components most people are interested in, in marijuana. There are terpenes that give it a nice smell/flavor, and have a mild mood effect as well, but THC and CBD are the ones that keep us coming back.

Weed doesn't tend to have free THC or CBD present, not great if you plan to eat it or take an extract. It is only present in a bio-inactive, "precursor" form known as THCA and CBDA. These are the acid forms of the molecule. Nothing dangerously acidic or associated with LSD, just a compound related to THC/CBD in the form of a carboxylic acid. The most common example of a carboxylic acid we run into is vinegar (5% acetic acid - aka ethanoic acid or methane carboxylic acid).

We can get high via smoking pot, because heat converts THCA into THC (through a heat catalyzed decarboxylation reaction).

Both THCA and CBDA are converted to THC and CBD through heat, with the carboxylic acid group converting to carbon dioxide.

Now the important part - how hot and how long. Unfortunately, reality doesn't give us simply answers. The full answer implies that the higher the heat, the shorter the time required, but at a loss of the nice smelling terpenes.

The most typical answer given is 145 degrees centigrade for 15 to 45 minutes, typically 30. For those of you who found high school science an unpleasant test of endurance, that translates to 293 degrees fahrenheit.

If you are doing this to plant matter, as many of us would be, ensure the material has been thoroughly dried at close to 200 degrees F. This prevents the heat from being used up evaporating water when your intention is to decarboxylate cannabinols.

Also, if you have a large amount of material (multi kilo range), this will increase your times, given it takes time to heat up material.

Temperature / times that can be used

212 deg F for 145 minutes
250 deg F for 60 minutes
293 deg F for 30 minutes

All of these will vaporize off most of the terpenes. I know of no simple way to retain these without a lot of effort and equipment not normally found outside an organic chemistry lab.

Word of warning
- most ovens are not extremely accurate and tend to cycle, with their temperature rising and falling above and below the target temp. Putting couple of bricks into your oven and preheating for an hour will help moderate these temperature spikes and may help protect your little THC and CBD molecules.
 
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PaleSun

Well-Known Member
Can anyone recommend the best way to 'do' the decarboxylation? My oven is WAY too difficult to hold such a constant temperature. I've heard of the "decarboxylation box", but have no idea what that is. Is this a home made gadget, commercial device, what?

Cheers
 

nivek

Photo of the Month: Oct 2018
i don't think one need get too technical with this. ovens have been used for centuries for this and will continue to be for eons

perfection is for scientists in laboratories

my still rule for decarbing is 110 at 110. 110 degrees celcius for 110 minutes. works for me, no need to fix it

cheers
 

oldsmokey

New Member
The best technique I've come across so far is Sweet Sue's technique de-carb and infuse all-in-one step with the instapot.
 

Radagast97

New Member
Can anyone recommend the best way to 'do' the decarboxylation? My oven is WAY too difficult to hold such a constant temperature. I've heard of the "decarboxylation box", but have no idea what that is. Is this a home made gadget, commercial device, what?

Cheers
Consider creating a box out of something with a high thermal capacity - such as bricks. Bring them up to temperature in an oven, using an infared thermometer (found at any cooking store or online) then place your material in the "box", for the allotted time. The thermal box will act as a capacitor to smooth out the fluctuations common to an oven.
 

onewarmguy

Well-Known Member
Hi all, when making bubble hash is it better to decarboxylate weed first before the process or the hash after the process.
Curious minds want to know.
 

Radagast97

New Member
I prefer decarboxylating the weed beforehand, given it also removes the water. For techniques having no advantage of dry weed, it doesn’t matter.
 

Stunger

Well-Known Member
Mitchell's link on decarboxylation of THCA is excellent, but a number of people might be a bit intimidated by the degree of science and chemistry in the paper so I thought I'd do my best to convert it into English. If I slip into the nerd zone, accept my apologies now.
Thanks for coming in with that! :)

THC and CBD are the primary bioactive components most people are interested in, in marijuana. There are terpenes that give it a nice smell/flavor, and have a mild mood effect as well, but THC and CBD are the ones that keep us coming back.
That's what I understood too, or at least that is how it is commonly explained. I think there are supposed to be 100's of different cannabinoids of which THC and CBD are mostly the only ones that get mentioned. I wonder how much those others contribute to the pleasantness of the plant's high, it must be complicated to test them all out, but all the same is it that only THC and CBD are mostly mentioned because we know the others are not significant, or because it is assumed that the other cannabinoids only contribute on a much lower level? Some folk like the stronger THC% the more the better, but other folk say they prefer not necessarily the strongest THC% strain but some lesser one where in spite of a lower % the 'sum of all the parts' gives an effect that they prefer more, I wonder do we know that THC and CBD are the key ones or do we just assume it.

Now the important part - how hot and how long. Unfortunately, reality doesn't give us simply answers. The full answer implies that the higher the heat, the shorter the time required, but at a loss of the nice smelling terpenes.
I was reading some articles that Shanel Lindsay wrote about decarboxylation, where she had a laboratory test the amounts of THCA successfully decarbed to THC from using methods like the kitchen oven/home methods and found that often a significant percentage was not decarbed (in the range of 10% - 30% give or take), so therefore the resulting edible or infusion was not getting the benefit of the full amount of THC possible from the herb because some of it was still remaining as THCA. Given that everyone has a different approaches of time and temperature it seems to me there is a general assumption that no matter what method and time/temperature is used, that full decarboxylation is assumed to be the result. I can't help thinking that unless a lab can show that a 'home method' is fully converting THCA to THC, then to assume it is fully decarbed may be wrong if instead it is only partially decarbed.
 

Radagast97

New Member
Most of the methods I've seen give from 5 to 15% undecarboxylate THCA. That's not unexpected. Even smoking you'll lose THC via destructive oxidation.

As a chemist, I'll tell you that 80% yield is considered an great yield, when running a synthesis.
 
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bebecillo

Well-Known Member
You know what's the best method for decarbing? one of these mofos

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This youtube video explains how they work, in case you want to understand why they're the best method.

When using a rice cooker, as long as there is water in whatever you're cooking, temps won't go over 100C, which means you have an electromecanic device that won't go over that temp no matter what (if you have more money, a digital air fryer is an upgrade)

Personally, after I boil the plant mass in water 3-5 times to remove chlorophyl and other nasty stuff, I throw it on the rice cooker, set to cook and add water everytime the device goes from cook to warm. This is specially helpful if you're making oil, butter or any other fat infusion. This would technically help if you're using alcohol to extract THC in warm mode, but I haven't gone that route yet. You know you will get uniform heat, you know your cannabis won't go over 100C and you're gonna be able to make the most of what you have.

Don't believe me? grind some weed, add a couple butter sticks and a liter of water/milk and let it do its job. You will be amazed at how easy it is.
 

Icemud

Member of the Month: July 2012, July 2014 - Nug of the Month: July 2012
Great read and information!

One thing that is also important is to pay attention to your temperatures when decarbing, and to remember that Terpenes are volatile and some have very low vaporization points, so the trick is to also consider these boiling points when decarbing so you don't lose too much of your terps.

Also, another good point to bring up... A lot of the extraction market now is starting to use "fresh frozen" biomass to make products like LLR (liquid live resin) and other "live" extracts.....(Fresh frozen, is when the plants are flash frozen immediately after they are cut down, no drying, no curing, just immediately frozen. This preserves a lot of the terpenes and volatile chemicals that would normally evaporate when dried).

The way to tell that you are truly getting "live resin" and not being sold distillate, is to look at the lab results.. A liquid live resin cart will generally have a much higher THCa percentage than D9THC....which shows it was lightly heated but not decarbed. If you buy a cart with a very high D9THC but low THCa, then most likely the cart is using distillate with added terps, and you are losing the "full spectrum" which is what is special about LLR and "live" extracts.

Great article and very informative.
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
One thing that is also important is to pay attention to your temperatures when decarbing, and to remember that Terpenes are volatile and some have very low vaporization points, so the trick is to also consider these boiling points when decarbing so you don't lose too much of your terps.

Pack a small watertight metal container full of bud and chuck it into a pot full of boiling water, and keep it at a rolling boil for three hours (yes, you'll have to add more water along the way, and it's best to add water that's as hot as possible). Where are the terpenes going to go, lol?
 

Icemud

Member of the Month: July 2012, July 2014 - Nug of the Month: July 2012
Pack a small watertight metal container full of bud and chuck it into a pot full of boiling water, and keep it at a rolling boil for three hours (yes, you'll have to add more water along the way, and it's best to add water that's as hot as possible). Where are the terpenes going to go, lol?
They could become a gas, and interact with other compounds in the sealed container, which could potentially cause harmful bi-products. The terpenes could also separate and end up on the sides of the container as the process above is very much like fractional steam distillation, without the fractional part... The real issue though would be what materials the container and seal are made from.... and if the terpenes were to interact.

I was working for a large legal manufacture and in partnership with a very well known testing lab. We always would test our products for all Cat3 test requirements before packaging, and then also the products would be tested as required before entering the legal market. We started to use new packaging from a different supplier, and all of our Pre-tests were clean, but started failing the Post-Packaging compliance test. (same tests, same product, only difference was time and package). We could not figure out what was happening. How do you test something that is clean, and then later it failed for residual solvents...??? We looked at everything and even tested all the packaging... and we finally found a solution. It was the jar lids!

The new packaging we were using, had polyethylene seals in the jars... The terpenes were becoming a gas and as solvents were interacting with the polyethylene seals, and forming a by-product, Ethylene Oxide. Ethylene Oxide is extremely harmful and mutagenic at extremely low amounts. This was being formed in the individual jars after they were packaged and sealed, and the jars were always stored at below room temp... luckilly none of these products were released but it could have been extremely hazardous to people if these interactions were not caught by testing. Anyhow, this is very unlikely, but could happen... therefore its always best to make sure to always use food grade materials.

Also, by sealing the jar and heating it, you are creating pressure within the container so when heated, it could expand/crack/pop/leak.. not a big issue, but may lose your concentrates.. or cause a mess. Also, because of the buildup of pressure inside the sealed container, this may influence the boiling points of some of the compounds so you would have to compensate for that.

Also to add.. .some terpenes are extremely flammable, so by concentrating them into a pressured device and being around spark or flame.. although unlikely, accidents could happen if the LEL was reached with the air/fuel ratio.
 
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Pahval

Member
Thank you very much @Icemud for this info, this may save someones life, ill spread the word around about this... Ive had my issues with those jars as well, as i saw people use it with pressure cooker, but the rubber/pet seals just dont seem well tought about in my head, im glad you did your test and found out about it... Ill add here what i found out about decarboxylation from 2 studies, which i found most helpful about this, and ill link my google drive folder with all studies i researched, most i discarded as they werent so helpful or were using material i was not interested in (like pressed hemp seeds oil)...

@MITCHELL FLORN can you please post new link, this one seems broken?

Cannabinoid Decarboxylation: A Comparative Kinetic Study

Overview of the processes involved in cannabinoids transformation...

Cannabinoid Decarboxylation A Comparative Kinetic Study pdf.jpg


This study investigates different temperatures and timings of decarb for all main cannabinoids, both with and without present oxygen.

Summary:

They used data from oven decarbed herb material to find prediction models of THC and CBD for total decarboxylation, but unfortunately they didnt show the losses you get while going for total decarb, as there will be shown in next study. Prediction model based on decarb kinetic for THC shows that best variables for total decarb are 160°C (320°F) for 6.5 minutes, and for CBD are 90°C (194°F) for 12 hours, 100°C (212°F) for 6 hours, 110°C (230°F) for 3 hours.

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This setpoint may be useful for commercial production, but for home oil producer, it may bring too big of losses to final oil yield...

Eyeballing of data graphs for extracted cannabinoids show that the best (meaning not total decarb, but most decarbed yield with some precursor cannabinoids still left) temperature and timing for THC decarb is 140°C (284°F) for 20 minutes, for CBD is 120°C (248) for 50 minutes, for CBG is 120°C (120°F) for 50 minutes also.

Cannabinoid Decarboxylation A Comparative Kinetic Study pdf (3).jpg


When decarbed at 140°C (284°F) for 20 minutes, THC shows no significant degradation to CBN in any method (thin or thick bed of material, nitrogen filled pouches).

Cannabinoid Decarboxylation A Comparative Kinetic Study pdf(4).png




Decarboxylation Study of Acidic Cannabinoids: A Novel Approach Using Ultra-High-Performance Supercritical Fluid Chromatography/Photodiode Array-Mass Spectrometry

This study is focused on decarb of cannabinoid oil extracts in vacuum oven. Since it involved different material (oil extract vs dry herb from above), some decarb variables are different, but what i found most useful was the data of how much there is a loss of material for CBD and CBG.

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Total THCa decarb is achieved at temps of 110°C, 130°C and 145°C (230°F, 266°F and 293°F) after 30, 9 and 6 minutes, with a loss of total molar concentration at temp of 110°C being 7.94%.

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Since decarb was done in vacuum oven, no oxidative transformation of THC to CBN was seen.


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Total CBDa decarb is achieved at 110°C and 130°C after 45 and 20 minutes, with a loss with first temp being 18.05% and with second 25.2%.

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They also showed how degradation of CBDa happened due to other biological material being present in extract, or some other unknown factors, compared to degradation of pure CBDa.

Decarboxylation Study of Acidic Cannabinoids A Novel Approach Us[...](3).png

Total decarb of CBG was achieved at temp of 110°C after 40 minutes, with loss of 52.67% of total molar concentration.

Decarboxylation Study of Acidic Cannabinoids A Novel Approach Us[...](2).png


My conclusion:

I will personally follow data from first study, aiming at highest yield, preserving some carbolyc acid forms as they are also proven to have health benefits, decarbing of herb material before extraction. It seems herb has to be covered with something like a lid or aluminium foil while in oven. Oven temps usually fluctuate about 20°F above and below (11°C) setpoints if undisturbed (not opened), but it shouldnt be a problem.


*edit: somehow this post is showing some pictures below, i cannot remove them :/

Peace...

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Pahval

Member
I would go for CBD temperatures... THC was shown to be most resiliant, and if you cover your pot and prevent any air moving you should have no oxydation of THC to CBN... How did you do it so far?
 
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