Freeze Drying Bud and Commercial Freeze Dryers

Discussion in 'Harvesting And Curing' started by Stoner Smurf, Jan 13, 2011.


    BobCajun Well-Known Member

    You don't need liquid nitrogen. In fact you don't even have to freeze the material first. The vacuum itself causes it to freeze due to the heat loss caused by the water evaporation. Apparently prefreezing does have benefits though. If you let it freeze just by the vacuum there can be frothing (see page). You do need some slight heating to avoid it getting too cold which would interfere with the drying. I don't know what temperature would be best to maintain it at, probably a little below 0 C.

    This does seem to be the premium method for drying though. A 12 or even 24 hour drying time would be pretty sweet, and having buds that look almost exactly like they did when they were picked. Could be a little bulky though, for handling. Oddly enough, when you search "Cannabis freeze drier" you get nothing but Harvestright, $3000. If you go to Best Value Vacs you can buy vacuum chambers fairly cheap though. That would be a start for making a DIY unit. Just need a vacuum pump and a water trap. The chambers are a little small though, if you want to dry much product.
    mr. childs likes this.
    Handy Mandy

    Handy Mandy New Member

    So do the buds come out crispy like chips or will they remain sticky dense nuggets

    BobCajun Well-Known Member

    That post I made earlier was regarding commercial or lab freeze driers, that the vacuum alone would freeze the material. Apparently the page I linked is dead now, but anyway that was just from a quick search I had done about freeze drying, I never actually freeze dried anything before.

    The reason I'm posting here now is because I saw a video where it showed that you can freeze dry small amounts of foods by using an airtight container with a desiccant in it and applying a vacuum using a "wine preserver" vacuum pump and special stopper. I have everything ready. I used Tritan food containers, they have a rubber seal and locking flaps and are thick walled and solid. Drilled a cork hole in the lid and stuck a vacuum cork in it and the pump was able to cause the lid to suck down considerably and it held overnight as a test. I also got a bag of calcium chloride pellets, used to refill "moisture absorbers", as the desiccant. It liquifies when it absorbs moisture so I'll have to put it in a separate small container and sit that inside the main container so the plant material can't get contaminated. I'll test it out in a while when I need it. I'll probably let the material wilt for about 24-48 hours to reduce the volume first.

    Oddly, you don't see many articles on the subject of freeze drying bud. There's no YT videos at all, just on freeze drying in general. Seems like an obvious thing to do to get pretty and flavorful weed. You can let it dry enough that it looks the way you like and then retain it in that condition when fully dry, or at the desired rh. I think I might flatten it somewhat though, for space saving.

    Last edited: Apr 24, 2017
    rikdabrick likes this.

    Budzbuddha Well-Known Member

    Yeah sure

    sadanimalknight Member

    Looks like I may be of help....

    I just so happen to have a freeze drier! I haven’t messed with freeze drying buds before but for the last year I’ve been shoving whatever I can in there to see how it does.

    I just trimmed some of my Gorilla Glue #4 a little early to give it a try.

    I have a handful of nugs that I will freeze dry and another group I’ll dry and cure regularly.

    I haven’t read Ed Rosenthal's Marijuana Grower's Handbook but I do believe I saw somewhere that the terps are best preserved if the temperature in the chamber stays below 75-80° so I’ve set my unit up to freeze overnight and heat the chamber to 70° When it kicks over to drying.

    It will take about 24hr for it to complete a cycle so I’d have at least some news here in a few days.

    Unfortunately, the “control” to this experiment won’t be done for a while but I can at least update on how the freeze dried product comes out.

    Here’s some of what I’m going to be running... AB61FA05-90E5-40BB-B08F-92F556A3490D.jpeg

    And the other half in my freeze drier.

    I’ll post back tomorrow after the unit has cycled and share what I experience.
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    Cold$moke Well-Known Member

    Wont the freezing just break the terpenes off?

    Like dry ice extraction?

    sadanimalknight Member

    You know, I don’t know. I just recently started growing and just so happened to have an actual freeze drier. I was curious if anyone else had done this and good old google had this as the top hit.
    Instead of starting a new thread with my 2 cents, i figured I’d just throw in. I saw this thread was originally started in ‘11 but has remained opened and occasionally bumped so no harm right?

    And a good way to finally post and contribute instead of lurk.
    Possum1 and Uncle Reefer like this.

    Cold$moke Well-Known Member

    Nope no harm at all science changes every day.

    Was just wondering cause im like dont i use dry ice for breaking the terpenes off? Lol

    I know i sure as hell dont know it all :)

    If it works your onto something :peace:

    Cold$moke Well-Known Member

    @sadanimalknight i sure as hell would be using it for makeing extracts for sure

    sadanimalknight Member

    Funny enough, I’ve been running extracts I’ve gotten locally through it to see if they have been purged correctly, it’s been interesting to see cheap(er) extracts that stay solid (indicating no left over solvent) and other more expensive extracts foam up and then settle down and solidify.
    I am also interested to see if the terps will sublimate and if so, at what vacuum. This unit is semi-automatic with only the length of freeze and drying times along with drying rack temperatures being able to be adjusted.

    Having this freeze drier has been a never ending science experiment on what can and can not be preserved.
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    sadanimalknight Member

    Don’t you mean the trics?

    I thought terpenes were the “smell and flavor” and the trichomes were the actual thc containing part of the calyx...
    Uncle Reefer and Cold$moke like this.

    Cold$moke Well-Known Member

    Oh my bad i thought the terpenes where in the trichomes but
    Yes i ment trichs :)

    I thought thats why the extracts are yummy is because its pure terpenes? From the trichs?

    Not an expert though
    docter likes this.

    sadanimalknight Member

    I’m no master grower, but I believe the trick will be pulling the nugs out of the freeze drier before they are 100% dried. That way they won’t be fragile and I won’t break off all the tricomes when moving them to a jar to finish.

    From freeze drying food I’ve found that you can think you’re stuff is 100% dry but if one little part anywhere is still moist at all, it will “rehydrate” whatever is around it. That’s bad for my food stores but that’s exactly what I want for my nugs. I’m hoping I can pull them out before they are 100% dry so that way I don’t have to rehydrate them. Just pop in a jar and let equalize. I figure, if I’m able pull the nugs out when they contain about 10% of the water they had, they would be ready for curing.

    If I really wanted to get into it, I could weigh the flowers wet and then periodically throughout the process reweigh them until a desired weight was achieved. You’d have to know an approximate dry weight for your flowers to effectively calculate the water weight. That can be solved by fully drying one nug from the same plant and weighing the before and after.
    I’m sure there are rough calculations for this floating around here or elsewhere for calculating a harvest, but to get as close to the optimal amount of moisture you want in your product, it would likely be best to just run a sample and calculate your own harvests moisture/weight content.

    That’s all fun and whatnot, but for now, I’m just going to see how well it does at drying.

    Im thinking it’s going to be a great way to quickly dry my flowers while maximizing the preservation of smell and taste but it is not a replacement for traditional curing that will further the “ripening” of said flower.

    I’m really intrigued to see if this makes a finer end product or if it produces a flower that’s as good as longer traditional dry and cure regimes just in shorter time.

    I guess we will see!

    sadanimalknight Member

    As an update, I’ve stopped the freeze drier to take a look at how everything is coming along.

    First thing I’ve noticed is that the flowers look almost identical to when I put them in. After careful investigating I’ve found the denser nugs and thicker stems are still frozen and will require more time. However I did manage to find a few bits that seemed just right enough to test.

    Not bad!

    Now, granted I don’t have any of my other stuff to compare flavors and smell to, but, I will say that I am definitely impressed with the amount of flavor and smell that is present after only have been drying for about 8 hours. I will say the taste is a little on the green side. Being a little early to harvest and fresh cut, I’m not surprised though.

    As you can see, it looks as green and perky as they did when I put them in there. E9D73162-68CE-46DF-A8DE-ADE87A9F659D.jpeg

    And for any of you geeks out there, here’s some thermal imaging as well.
    As you can see, there is plenty of water left to sublimate out. It will probably take the rest of the day as originally planned.

    I do have to say, I’m happy with the potency of my stuff! You know it’s good when you spend a good 10 min blankly staring at the screen pondering what to say next.

    I definitely see promising results!
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    sadanimalknight Member

    Well as promised, here’s an update.

    In just under 12 hours I have gone from frozen to dry! I’ve whisked my nugs out of the drier and straight into the second phase of my experiment which I’m going to do a write up about as soon as I can.

    For now, I can say that the one flower the SO and I did sample tasted and hit just like most club weed. Taste and smell was there. Subtle, a little harsh on the throat, but all around a good smoke.
    Now that I’m on to my curing stage, it will be interesting to see how this pans out.

    So far, I’m impressed. From plant to good smokable product in under 24 hours!
    I’m gonna save all the good photos for my write up but here’s the end product

    . FAD2AAC8-0221-477A-B277-7BF86009569B.jpeg

    HookahsGarden Well-Known Member


    Home freeze dryer for beef jerky.
    Home models $1800us

    sadanimalknight Member

    Yep, that’s the Harvest Right freeze drier I use. I have the standard model that was nearly 4K just a year ago. Good to see the price has dropped (those fuckers)

    I bought mine because I’m a pretty serious camper, hunter, and a little bit of a prepper.
    I love that I can make my own “mountain house” meals which are way tastier than anything store bought. I also love preserving seasonal veggies and fruits to enjoy whenever. And with a supposed 25 year shelf life, I do mean whenever! Also there is no better look than that of your hungry hunting buddy when you bust out a full thanks giving meal when in the bush for two weeks.

    Some things dry really well and others horribly. But this thread is about the ability to quickly dry and preserve herbs... which it does exceptionally well it seems.

    I do know I replaced the vac pump shortly after getting it. It’s way louder than the 60-70db they claim and I never liked JB brand anything....

    I went and got a premium 2 stage 7cfm vac pump and have had no issues since. I almost wish they had an upgrade option to get a yellow jacket or something... oh well, I’m happy with my unit.


    Not that it matters, but I wouldn’t attempt to make beef jerky in a freeze drier. Anything put in raw will dry out raw. That means the bacteria is still very much present. You preserve the food by placing it in an airtight container along with an O2 scavenger. The lack of any moisture along with this prevents most* bacteria from breeding and spreading to a hazardous level. Any raw meats should always be cooked after rehydrating to kill off any errant bugs.

    *I also say most bacteria from spreading because botulism actually can grow in a no/low oxygen environment. Ensuring the food is absolutely dry is also important. But cleanliness is most important as it is in any food production facility.
    Last edited: Jan 8, 2018

    mothersfinest Well-Known Member

    Wow I sort of randomly was looking into just this and am astonished this tread is current. Post from today? woohoo! Didn't have to sign up or anything, already a member for this resource lol. This is awesome guys! I guess i am going to be buying a freeze dryer. Lol I'm glad the sites are still alive. Still miss OverGrow. I would recommend hanging the herb for a brief period of time to get that more standard hung look, just for appearance if nothing more. Man this almost has a strange de ja vu vibe just finding this lol.
    sadanimalknight likes this.
    Uncle Reefer

    Uncle Reefer Well-Known Member

    Very interesting, subcribed

    sadanimalknight Member

    I am going to write up all the progress tomorrow (hopefully) once I have some time to sit down and breathe. But for now, I’m going to say you are on to something. One biggest difference between hang dry and freeze dry is that the freeze dried flowers stay preserved almost exactly as they were when you put them in whereas the hang dry gets dense as it shrivels up.

    I will say I’m happy with the freeze dried product. It can be consumed right out of the unit or cured as normal. So far things look good.

    I am actually doing a few experiments right now, I may just start a new thread and share my experience in whole.

    I’m also working on gathering up all my stuff for a journal. I’ve done my room from the ground up so lots of fun to share.

    Stay tuned!
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