Decarb – You’re Probably Doing It Wrong

Jessica McKeil April 24, 2019 46 comments

Cooking cannabis has a science to it. If you want the most from your medicine, read on.

You’ve stepped into your kitchen with a jar of fresh flower in hand. With a recipe in mind, the first step to cooking cannabis is the activate it. You haphazardly throw it on a baking sheet, place it in a hot oven, and wait 30 minutes for the medicine to release. It’s a tried and true method of turning fresh cannabis into potent medicine – right?

According to many experienced cannabis cooks, the normal decarbing process we’ve all come to rely on may not be as effective as once thought. Not only does it make your home (and maybe apartment complex) smell like a commercial cannabis grow-op, it releases the valuable compounds into the air.

The heat triggers evaporation, and it’s this evaporation that pulls the cannabinoids out of the plant and into the atmosphere. The potent infusion you planned on making may contain far less medicinal content than you expected.

There is an easy way to avoid the strong aroma and the loss of medicinal value. A more experienced cannabis chef can tell you cooking cannabis in a mason jar will reduce the pungent smell of cooking cannabis, and more effectively capture the medicine. The complete directions for dry and wet decarbing in a mason jar follow.

[bsa_pro_ad_space id=25]

cooking cannabis, decarb, weed, whats in your jar, cannabis, marijuana, cooking cannabis the right way,

The Benefits of the Decarboxylation Process

Most cannabis recipes call for decarboxylation before you get cooking. The process, commonly called decarbing, uses heat (over time) to activate the raw cannabinoids into the active versions. The dried plant contains dozens of different cannabinoids, but most of them are inactive. The compounds most of us are looking for, THC and CBD, have a slightly different molecular structure before activated. They are tetrahydrocannabinolic acid (THCa) and cannabidiolic acid (CBDa).

Do THCa and CBDs have medicinal benefits? There is a growing evidence that they do. For example, THCa may help with pediatric epilepsy, and CBDa may have anti-inflammatory benefits. There is little information available right now, as is true of many secondary cannabinoids under active research. However, most people using cannabis for medicinal applications today are in search of the activated versions of these cannabinoids – THC and CBD. If you are making medibles at home, chances are you want THC, not THCa.

How to Prevent Cannabinoid Loss During Decarbing

Instead of throwing your raw cannabis on to a baking sheet and into the oven, there is an effective alternative to consider. A simple mason jar in a water bath locks in the cannabinoids and terpenes, instead of allowing them to evaporate. Plus, for those who don’t want to release the potent-cannabis smell throughout their house or apartment building, you’ll also have better control over the terpene release.

[bsa_pro_ad_space id=26]

decarboxylation, cannabis, medical cannabis, recreational cannabis, medibles, CBD, THC, THCa, CBDa, cannabinoids, decarbing

What You’ll Need:

  • ½ quart mason jar (with lid)
  • Pot
  • Water
  • 0.5 to 1 oz cannabis (Don’t jam it in. Leave room at the top. Bud density will determine how much you can get into the QT jar.)


  1. Roughly grind the raw cannabis and place into the jar. Tightly seal the jar.
  2. Fill a pot about halfway with water, and place on the stove top on low to medium heat. Make sure the height of the water level is not going to cover over the jar.
  3. Place the jar in the pot of water before it heats up. If you put the jar in after the water has come to a simmer, the jar will likely crack or explode. You will also note that the heat doesn’t surpass 212 F (the boiling point of water).
  4. Bring the water to a low simmer with the jar in place. Simmer for up to 90 min. Make sure the water does not evaporate while you are decarbing! 
  5. Remove from heat and allow to cool. Do not remove the lid until completely cooled, as this may release the terpenes (aroma) and some of the valuable compounds you were looking to capture.

The Set-it and Forget it Decarbing Process

Cooking cannabis using the method above is easy and doesn’t require any special kitchen equipment. You will need to keep a close eye on the setup while on the stove top though. It’s not safe to leave a stovetop unattended while cooking cannabis.

If you don’t have the patience to babysit your decarbing mason jar, invest in a slow cooker. While the full decarboxylation process will take much longer, you can essentially set it and forget it while it’s going through the magical activation process.


What You’ll Need:

  • ½ quart mason jar (with lid)
  • Slow cooker
  • Water
  • 1 oz cannabis


  1. Roughly grind the raw cannabis and place into the jar. Seal the jar.
  2. Place the jar inside the slow cooker, and cover with water. Again, it’s crucial to bring the slow cooker and the jar of cannabis up to heat simultaneously.
  3. Set on high (around 212 F), and simmer for four hours (alternately, set on low and simmer for eight).
  4. Remove from heat and allow to cool. Do not remove the lid until completely cooled, as once more this may release the terpenes (aroma) and some of the valuable compounds you were looking to capture.

How to Make Cannabis Infusions Using the Mason Jar Method

Want to kill two birds with one stone? Prepare your infusion at the very same time you are decarbing. Place the carrier oil and the cannabis in the jar before setting into the water bath. Use enough coconut oil, olive oil, or other fat to completely cover the plant material. Whether you use the simple pot-on-stove method or use the slow cooker, follow the same steps. At the end of the decarbing process, strain and discard the leftover organic plant material.

decarboxylation, cannabis, medical cannabis, recreational cannabis, medibles, CBD, THC, THCa, CBDa, cannabinoids, decarbing

Incorporate the infused cannabis oil into any recipe, as you would with the non-potent version. Coconut oil, olive oil, and avocado oil are all great options. 

Next time you are headed into the kitchen to cook with cannabis, consider the mason-jar method of decarbing. Whether you are making candies or cookies, the final product is likely much better. Perhaps your neighbors will appreciate the lower pungency, but the final edible may contain higher medicinal value than the cookie-sheet method.

Author avatar

Jessica McKeil

Jessica McKeil is a freelance writer focused on the medical marijuana industry, from production methods to medicinal applications. She is lucky enough to live in beautiful British Columbia, Canada where the cannabis industry is exploding. When not writing, she spends much of her time exploring in the coastal forests.


  1. Jaye Bublet

    Huh. I thought 212F was too low a temp to decarb at.

    • Jennifer Grant

      212F is the temp at which water boils. That simmer will decarb the flower in the glass jar over prescribed time. You can’t get higher temp in a water bath (without using pressure cooker). This decarb is slow and preserves terpenes, but is not efficient. It does, however, produce a better result than oven. You’d really need to purchase something like Nova to get the perfect decarb.

    • Dave G

      212 F is fine, but it will be slower. Another article on the RxLeaf website ( ) recommends 220 to 240 F and cooking in the oven. Seems easy enough to put the jars in the oven. The jars and oil will help even out the temperature cycles of the oven. The time required for jars would be a bit longer allowing for heat to transfer into the jar. For an oil infusion, I would preheat the oil to ~120 F – warm but still handle-able.
      This paper ( ) includes a chart with a set of time/temperature exposures out to about 1 hour for both THC and CBD.
      Also note, if your location is at higher elevation (ex Rocky Mountain states), the boiling temperature of water will be lower. At 5000 ft, water boils at about 203 F.

  2. Buck

    Really just a question for clarification…. 7 ounces of flower product?? I don’t think 7 ounces will fit in a 1/2 quart (pint) Mason jar. Other than that, I really like this method. I use a similar one to this for making my evape oil. I will be modifying my method to yours…. (except for the 7 ounces part)

  3. awa keened

    Heat shouldn’t exceed 160F. Make Rick Simpson oil instead. Watch Run From The Cure.

    • Jennifer Grant

      The water bath method calls for the water to approach 212F so that it can simmer and lead to decarb of the cannabis in the jar. RSO is a total different method.

  4. H Maier

    Can you smoke it after doing this process? Effects? TY

    • Jennifer Grant

      You don’t need to decarb before you smoke it. The heat of smoking/vaping process is enough.

    • Joe

      You can. Might be really dry and harsh with a nutty or burnt popcorn taste to it, but the purpose of decarbing is to activate thc for consumtion by removing carbon atoms with heat. When combusted or vaped the carbon is released and the thc is available. So the short answer is there is no removal of thc (well, some may be lost), just carbon and terpenes which would still make it smokable

  5. Teresa Trainor

    This is all new to me. I have been researching this and thought about the water bath method too (old fashioned “canning” really). I’m going to test it out soon. I plan to use a candy thermometer to monitor the water temp. So glad to find this article…tells me I’m on the right track. I’m going to do it in small 4oz Ball canning jars. And keep my chem lab nite book 🙂 got my grinder and digital scale that measures grams! One question though: will I be able to add a small amount to my chai tea in an infuser once I decarb and have a nice cup of potent tea?

    • Jennifer Grant

      Yes! I am going to try the same project this weekend. We’ll have to compare notes. 🙂

  6. Teresa Trainor

    Are you going to try mixing with loose tea in an infuser? I’m doing the water bath method now ?

  7. Christina Brown

    Can you decarb a batch in mason jars, then store it safely in the unopened jars for extended periods (months)?

  8. Jillian Lemmond

    I have a levo machine with a max temp of 200 f. And want to decarboxylaze directly in the avacado oil so it’s all one step. Looks like I would need to set it at max temp and increase the time (5-6 hours???) To get a full CBD decarbing as it infuses the oil???? Maybe longer?? What would you suggest?

  9. Rob S

    I’m a bit late on this thread but couldn’t you add some salt to your water to increase the temp to about 220deg F? More salt would raise the boiling point to an even higher temp. This would speed up the water bath decarb process a bit. At 220deg F how long would the process take? Thoughts?

  10. Charlie

    Ok so I can decarb the bud, then after its decarbed just put my choice of fat in the jar then keep the jar in the water bath?

    • Jennifer Grant

      Hi Charlie – if you want to use the water bath method and infuse into the fat of your choice at the same time, then yes. You grind the bud and add the fat of your choice. A basic rule of thumb is enough to cover the bud. THEN into the water bath as described (slow cooker versus stove top). You are decarbing and infusing at the same time. Once it’s done, strain and you’re good to go.

  11. Tony

    The mason jar method works great for decarb.
    I have used a convection oven for even temperature.
    Checked with an accurate oven thermometer and doesn’t vary more than three degrees F.
    Perfect for careful decarb. Oven can be set for anywhere between 220 and 240 which appears to be the recommended range. Then put the mason jar on a cookie sheet with a tea towel as a cushion and then all you need to do is decide on temp and time. I have not yet experimented with different temps yet but that would require a lab to test the results accurately. 235F for 60 minutes provided great results. I have used it in tea as is and also infused it in the same jar as described with coconut oil. Same oven at 170F for four hours. Worked great. It should be possible through testing to find the ideal temps and times.
    I do not use enough to justify doing the testing myself but one half teaspoon of the infused oil is perfect for a 6 hour session of relief and or fun.

  12. Tony

    Silly Tony forgot to put in quantities. 1/8 of Sativa and 1/8 of Indica. 1/2 cup of coconut oil.

  13. Jim

    Who can afford 7 ounces at one time?

  14. B Urquhart

    Just attempted my 1st go round with the mason jar decarb… worked GREAT! Broke 8 grams weed up into pieces (like you would if rolling a joint) put it in the jar, used a piece of tinfoil under the ring, and let it go for 1 1/2 hrs. Let it cool, put 2 cups butter in the same jar using a piece of foil again,and back into the water bath for 2 hours……made a batch of cookies, and they are outstanding! So glad I found this page…..
    Just one question: do you have to clarify the butter 1st? I did, but it seems like you loose a little…..thoughts?

  15. Dianne

    I’ve been doing the mason jar decarboxylation & infusion method, in one step via bain-marie, for CBD dominant cannabis & it works beautifully! When I separate the coconut oil from the cannabis plant matter, in order to make my CBD caps, I also use the left over coconut soaked plant material(solid at room temp). I put this in a bowl in the fridge & when I make a cup of tea I add some of this soaked plant material to the hot tea & 30 secs later strain the plant matter off & drink my tea.
    Note: Bernardin mason jar lids after 2015 are BPA free.

  16. Lee Brandt

    You don’t use Lecithin Granules when making oil ?

    • Dianne

      Hi Lee,
      I’ve read that lecithin is an emulsifying agent which basically binds certain liquids that normally don’t mix together, so it might be an added asset where many ingredients are involved. So in that respect it doesn’t pertain to my case as cannabinoids are lipid as is coconut oil which are the only ingredients used to make my CBD caps. In my case adding lecithin might interfere with the gelatin capsules stability(ability to remain in solid form) – not sure though. As for lecithin increasing bioavailability; thus far I haven’t found any science backing this up but there are many subjective reports out there by folks who swear by it. If lecithin alone were to successfully bind cannabinoid molecules to water molecules then why are some large cannabis firms spending millions on nano-emulsion & nano-encapsulation research for the cannabis food & beverages sector?

  17. Thomas O'Keefe

    I did a coconut oil infusion in the slow cooker and when I let it sit in the Mason jar and separates into a dark layer the bottom and a lighter green coconut oil solid on the top.
    Have I done something wrong?

    • Chris Glazier

      I would deffinately open it and check for mold ect after it is done. Plus the fact is that cannabis decarbs itself during the 6 months setting in jars from green. You may still want to do it before you cook with it in the end as I have no idea how far the natural process wiuld be along at that point.

      Sorry it’s been awhile and no one answered you. It’s not my site but the oil and all or most all of the cannabinoids would have settled and congealed at the top. Just have to get rid of any water and leaf material to keep that for medicine of some kind.

  18. Chris Glazier

    My last answer was to two different posts. One directly at bottom and one a few up about separating the layers.

  19. Okay, so I’m trying the on-step decarb and infusion. I have an ounce of pot and 2 cups coconut oil sealed tight in the 1Qt mason jar. I put the jar in a slow cooker covered with water on high. Four hours is gonna do it?

  20. Shannon

    I followed this method and it worked great! I used avocado oil with hemp flower/bud … my next step is to infuse it with dried elderberries … thank you so much for sharing this!!

    • Jennifer Grant

      Thank you for sharing that, Shannon. That’s great! I love this method. Now, elderberries – I’ve never tried that. What do you use the oil for after that infusion? I’m intrigued.

  21. David Westberg

    Why doesn’t the jar explode during slow cooking? Doesn’t pressure inside jar result from slow cooking?

  22. Jonathan Lenfestey

    You had me untill you wanted to kill 2 birds with one stone by adding the oil to make your infusion as your bud is decarboxylating… the point of decarbing is to activate the THC BEFORE you make your infusion…

  23. Dominik

    Any experiences if its possible to decarb wet/fresh plant in the mason jar water bath?
    I know that the plant wont go over the boiling temperature of water if its wet, but the water bath wont get hotter anywhere, so it should work or am i wrong?

    • Jennifer Grant

      Hi Dominik – do you mean freshly harvested cannabis? You can decarb without curing/drying first. It will probably need longer time in the heat to compensate for the water content in the plant material.