So…they took out too much water and had to rehydrate? I do know that dryiing in the refrigerator gave a different and ‘greener fresher’ dried herb to cure. Freeze drying is just sublimation of the ice an old and good tech. Got to retain that 62% so for me it would be just running till you get that. Perhaps timed cycles above freezing to allow moisture to distribute evenly ?
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Yeah, sublimation/vacuum extraction is hardly a new technique hey… It’s probably first year chemistry 101 and as you pointed out definitely works , well enough to have removed entire oceans from the surface of Mars . A couple of things I don’t get though… unless there is some other process going on, the chlorophyll is staying put as far as I see it… and I am sure every person who has ever microwaved weed knows, it tastes awful. So then… how to deal with it? And also, why does the vacuum extraction technique not remove other volatile esters/terpenes that may be present? Maybe the vapour pressure point of frozen water is lower than that of any other volatile present but I would be surprised if this were the case. Steaming will degrade the chlorophyll, however everything volatile is lost… maybe some sort of re-fluxing system?
The most impressive is the very long story of this insane ratio. As old than the “guess the sex of plants by seed’s shape” or the legendary "boil your roots for more THC in buds " ^^ I’m sure we have now reached the half century with that … maybe the faulty concept of this ratio is specifically what is appreciated.
And like you said, if Ed and Jorges failed at it … it’s hopeless i think ^^
grams/KWh/m^3 would be the ultimate metric, but it’s more difficult to calculate.
Exactly. A pain to make it universal, but maybe the most responsive ratio to catch the benefits/prices of all type of changes (nutes, lights, regime …).
It sound like something to be coded with the “rationalized/watt-o-meterized” marketing of all our lights also ^^
I get the point, it can be elegant to best refine the volume required for a given line. Better than me discovering than SOGging the JH in one gal volume is better than 2 liters pots, in flowering a motherplant ^^
I personally use something derivative to consider the yield potential : the root mass. Nothing very advanced. I put the whole plant root mass in a water basin to remove everything, i gently dry it (pressing it on “papel towel for kitchen” = removing at max the weight of the residual water) then i weight it (i cut at the trunk base).
I use it as it but i also make a ratio between the root volume and the “wet” vegetal mass produced (for clones production and buds production). It help me to differentiate on similar specimens the true yielders from basic survivors just genetically made to survive on Mars.
I consider than at the moment you harvest enough weed to sustain your needs in homegrown context, there is no much considerations to have if you’re happy with what you got.
For me it’s a bit more stressfull. I can “lose” 5 grammers on flowered motherplants, i will not really give a fuck because it’s under the common variations between specimens.
But losing it on a Sogged clone is not a feedback from the crop I want to get. It mean than something gone really wrong and than i have to react fast to compensate the lack of grammers. Less than 20% lose on a clone don’t look like terrific, but when it happend 100 times for each sqm … you start to cry.
It’s when some metrics can be real companions informing you if you sux or outperform the standarts, also if you have made the right choice for your specimens eventually.
Also has anyone tried fitting 450 grams of weed into a even a cubic foot?
Never tryed that but an half kilogrammer in an half cubic meter is pretty easy without really compressing it ^^ I guess it’s a local joke on mexicans bricks than i can’t really taste lol
what I don’t get is how the chlorophyll is dealt with.
No deal at all, you get the bud as you put it inside but dryed. You can apply a six months curing after that or not, and never use this machine as a “buffer” in your stock management. It’s up to you.
“Moving water through the plant is the key. Environmental manipulation is just as important in the post-harvest process as manipulation is in the growing process. Curing is about water and resin—as you move water through the plant, it becomes a transfer vehicle and pushes the resin through the plant to the trichomes.”
I’ve understood what he have tryed to express, and there is nothing to have with freeze drying considerations.
He just tell fresh growers to don’t over water theyr plants just before harvesting them, like it’s writed in most guides as “flushing process”, and 90% of the time very badly interpreted lol Can be extended with nutes, final PH , acids use etc …
Now i have to correct a bit for the context this portion : “it becomes a transfer vehicle and pushes the resin through the plant to the trichomes”.
The danger is than the majority of fresh growers will consider it as a new “root boiler” technic if you don’t give enough details. Water is not and will never be a cannabinoid’s vehicle from let say the stems to the trichomes (it was lefty as fuck to present it like that imo). Because cannabinoids, or even let’s say the resin are produced “in site directly” and not with water electrolyze or something fancy, but with well known enzyms only. It’s chemistry, not logistic.
Perhaps timed cycles above freezing to allow moisture to distribute evenly ?
The machine do it for you. And it’s not a miracle this way to get an “aerated and expanded foam” in the grinder with a neville haze as impossible than it sound. Which is a bit more tricky to obtain with a traditional drying. This method of drying is no longer a debate in cups since years, it’s the place to discuss it if you’re interested to change your drying process imho.
the chlorophyll is staying put as far as I see it… and I am sure every person who has ever microwaved weed knows, it tastes awful.
The best weeds i’ve tasted in my life was green as fuck and relatively fresh. Chlorophyll is a fake ennemy, nutes profile and assimilation are the real subject on it for me.
To compare a “micro waved” weed with a freeze dryed weed is something bad to best figure out the concept. A micro wave will literally cook the weed in using the water of the vegetal mass, the vegetal mass becoming the “cooked mass” and the “pan” at a time, and the water inside the mass “the fire under the pan”. The resulting spinach is not only about the chlorophyll cooked in seconds.
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I agree that grams/watt is stupid. It tells you nothing useful at all.
I got really great gms/watt on my last grow - but it took 5 months to get that amount of weed. My previous grow had much lower grams/watt, but yielded me almost the exact same grams per day - it was just a shorter grow over all.
For most of us home growers, I dont see why you need to know more than grams/day yield. What it really comes down to in the end is - how much pot do I have when its all done and the mess is cleaned up?
It costs me about the same amount to grow on a daily basis no matter how long the grow is. Every day I use roughly the same amount of nutes and my electric bill is about the same every day. There are minor extra costs now and then, but the daily costs remain pretty much unchanged unless you expand or shrink your growing setup. So you can also judge your efficiency by the grams/day metric as well.
Adding in volume of the grow space is an interesting addition, but not that useful in the end for home growers. I dont give a hoot if the grow space is 4 ft tall or 16 ft tall. All that really matters is - did I grow enough during the season to fill my needs using the space I have?
I used to track costs per day or per gram early on, but I got tired of that once I figured out it was way cheaper to grow than buy pot at the store - even using relatively expensive hydro techniques.
Now, if you want to measure how big your d$ck is compared to the other guys, then you can start adding in things like square footage, or total volume of space or other details, and prove that you can grow more than the other guy with less - but does that really matter other than for bragging rights? Maybe it does if you’re limited in space or have to make a profit based on a fixed size space, grow in closets or PC cases, etc. I really admire you guys who do micro growing and get good yields from tiny spaces.
Dont get me wrong, I have no problem doing a little tiny bit of polite bragging once in a great while, and then humbly and graciously accepting congratulations and worship from the masses when I think Ive earned it, but the bottom line is how much pot do I have on hand at the end of the season.
Plus the math is easier 
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“Also has anyone tried fitting 450 grams of weed into a even a cubic foot? I am wondering where the air space goes?”
Lol its cuz you could be like 3 ft high so 450grams/3cu ft.
But even that is whack, thats only dried nugs w no sugar or fan leaves or stalks. Doesnt seem possible.
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Bro, I am thinking there is an element of Aussie humour that is gettign lost in translation here 
All good, I think we are on the same page…
You have raised a good point, I also have noticed that some of the weed I have had has been almost still living and seems to carry the plants flavour profile better than it does when dry. Cuban cigars can like this, you either smoke them freshlly rolled, or you age them for at LEAST 3 years and they taste great. Smoked at 12 months they taste acrid and horrible… but I still don’t know the underlying chemical reason for this change.
It makes sense that if terpenes are volotile then a method of drying/curing that uses lower temps is going to preserve more of the terps… this is why I justify not use a fan when drying. It seems to me that a closed cycle sub critical C02 system would be the way to go if rapid drying was a commercial need?
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Now we are talking about a big vice of mine : hand rolled cigars and blunts ^^ Cohiba’s are my poison, filled with goodness or not.
It exist twos big difference between a cigar and a nug of weed in term of evolution and “curing”.
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the tabacco leafs inside the cigar are allready dryed and cured (in stack, in barrels …) and cured (during months or years).
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the cigars don’t “evolve” in the way we see the things with the weed, it’s generally a blend in three layers with three different leafs sources : wrapper, filler (or weed ^^) and the intermediate binder. When you let sit your cigar at high RH for long term, you’re just “blending” the flavors of these three layers. Just like pipe’s smokers when they press theyr homemade blend, that’s the same finality and goals.
When you have a cigar with a very tastefull wrapper (like maduros), if you smoke it straight from the rolling station … you will just taste the wrapper because it cover the twos others leafs. It’s like feeling only the cinammon in a cinamon rolls, and nothing else. 6 months later, you discover a totally different cigar which is worth the price. Just because the wrapper sucked out the filler and binder flavors with the high RH of the cave, in losing intensity. There is not much chemicals transformation, it’s allready done in fact during the “leaf process”.
That’s the advantage to dry the weed directly in a wrapper/binder combo for months (thx Mc Muffin for the great inspiration lol). Freaking hot to watch out during months, but at the end you’re smoking something than is not existing in the nature : a totally fusionned flavor between tabacco leafs and weed, like melted. Luxury blunts i call that ^^
To give an idea, if you want exactly do the cigar way with weed, you have to blend three different weed in the jar and to wait than it give an unique “weed”. Never tryed but in knowing a bit about cannabinoids, i doubt than it’s possible. But the concept is there for the analogy.
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Ever smoke a Malawi Cob
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Interesting paper on this topic, with some details on the yields obtained by various commercial facilities.
It seems yield potential is simple to work out
Now why didn’t I think of that 
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Thats some interesting reading - but hard to get through. It seems to me they have made some assumptions that are not very good and the math is insanely hard to follow. Thats what happens when you get a statistician on the team I guess.
My main disagreement with them is they keep using Grams per watt like it some sort of absolute reference but they dont bother to add in time or sq footage or any other metric that would make gm/watt valid. Gm/watt all by itself is a meaningless metric for comparison - especially if you dont take time into account. One grow takes 5 months, grows trees and looks great on a gm/watt basis, but another grow that only takes 3 months, but makes more gm/day, looks crappy when you only look at gm/watt.
They did some other things that were similar but not as bad in my mind.
For example, they decided that the type of fertilizer made no difference because the gm/watt didnt change - but didnt take into account anything else - lie the time of the grow or space, etc.
I guess my main complaint is it seems they are taking some ‘stoner science’ as fact before actually testing it.
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Oh - and as far as 400gm/sq ft - they show some growers making 3500 gm/sq meter. Thats in the ball park of 1100gm/sq ft!!!
Oops - I am an idiot. The correct answer is 3500/10.76 = 325. So in line with the OP claims.
Thanks to @50State for keeping me honest!
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A meter squared is equal to 10.76 square feet this thread and article is all about bad math lol
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Oh no! I must be turning into a stoner to screw up like that!! 
Fixed it 
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Thanks for that. Bump for it being frigging sweet. What an awesome way to dry. I assume it would eliminate molding on super dense strains? Very nice. Ty
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It sounds cool, still learning about this…
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You could DIY a cryo dryer easily. All you need is a mini freezer, which you can buy used cheap, and a vacuum pump of some type, and a sealed container that will fit in the freezer and withstand vacuum. Any old pressure cooker or even a mason jar would work.
If you are really into cheap DIY, take the compressor from an old fridge. They make reasonably good vacuum pumps.
Or for a few bucks try this one. All you need is the freezer now.
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On second thought, you could do the freeze drying without ruining a mini freezer. What you do need is a sealed vacuum vessel along the lines of what is in the Amazon add.
Put your bud in the vessel and freeze the whole thing. Take it out and connect the vacuum pump and pump for s few minutes. Dont let things thaw.
Stick the vessel back in the freezer while its still under vacuum. Wait. The pressure will climb as the water sublimates. Every so often, take it out of the freezer and pump it down again. Repeat as needed.
If I can find my old refer condensor from my wing making days, I may give this a shot. I have an old pressure cooker that will work great. I will need to rig up a connector and shutoff valve to the stem where the weight sits and I will be good to go.
I wonder if there is enough interest to warrant splitting this off into its own Freeze drying thread?
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Quite a few interesting observations in that paper while noting they had two different light sources (MH and HPS). Some obvious, others interesting:
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THC was lower at a light intensity of 400W compared to 270 or 600W (edit, I’m guessing MH vs HPS).
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Increasing the duration of the flowering period led to increased THC for most varieties
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Increased plant density reduced THC for all varieties
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Increasing the pot size from 5 to 11 L reduced THC for White Widow but had a much smaller effect on other varieties
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Early Pearly produced lower THC compared other varieties when slow release fertilizer was applied (p = 0.0004) whereas for Super Skunk produced more THC compared to other varieties when either fertilizer was applied (p = 0.0017).
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Figure 4, yield decreased with increasing light intensity. But, some varieties show increased CBD concentration.
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THC and CBD per square meter increased with light intensity while yield per W decreased with increasing light intensity
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Yield per square meter was higher when HPS lamps were used than when MH lamps were used
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the effect of maximum temperature is interpreted as having the same effects as plant density, whereas the vegetative photoperiod had the inverse effect as density
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the effects of maximum temperature and duration of the vegetative growth period have effects that are the inverse of flowering duration effect
Of interest is item (6), photoihibition? Temperature?
I’m not sure how to interpret (10), do they have a fixed schedule and when do they start the bloom counter.
Also, they did not measure canopy PPFD but instead were using the power draw to the fixtures as a metric. Which, sadly, makes this paper something less useful. Seems to be an exercise in generating statistical formulations. They are missing some key metrics to make the observations more useful.
There are a lot of good references in that paper.
Their conclusions:
- low plant density (≤12 plants per square meter)
- a flowering period duration of 9 weeks (edit, for the phenotypes tested)
- the use of HPS lamps (edit, they only tested against MH and HPS)
- an adequate fertilizer regime
- manipulating light intensity to preserve high energy efficiency vs. favor THC and CBD accumulation
Thanks for posting.
[quote=“Larry3215, post:70, topic:21331”]
It seems to me they have made some assumptions that are not very good …
I’d agree.
Yes. The math is formatted such that it looks entirely too complicated but it’s not as bad once you understand what they’ve done. They’ve embedded the variables (differences between grows) as boolean logic (the 1’s and 0’s). When evaluating an equation, you’d select one particular variable (as true) and ignore the rest (as false) from the “matrix” looking portion of the equations.
It would be easier to interpret if they broke out individual equations but then there would be a lot of equation. They compressed the results in this way.
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Ok. There is a thread or two on the topic, I’ll move the relevant posts if we continue to move off-topic after this point.
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Still have not seen 300+ g per sqaure ft anywhere. Is that a wet weight ?