The physics of drying by desicator

Help Support and Requests
1

@cyclopath @IlluminatedExtractor @Lincoln20XX

Ok so electricity is an issue in the African highlands
As is shear volume

So 1 of the main things that should improve is the drying of flowers or kief since with the traditional process a LOT of the terpenes are lost to atmosphere you will hardly find hasj made in Marocaine with more than 1% terpene content hasj
A concentrate !!!

Freeze drying is not an option so I started playing with the disicator tech

Take a vessel place anhydrous calciumchloride in and place the flowers on top making sure they do not risk touching the salt
And it works flowers are dry in 6 days
Now this is easy at a small scale some filterplates and spools made the drying vessel

Flowers are less discolored
Terpenes are more present ( no data yet) but deffenatly true

But to implement at scale there are some variabels I played with and I would like to hear your thoughts

Although I have a hunch of what would be best I find it hard to find the scientific data since it s evaporation under different circumstances

So calciumchloride or silica gel ???
The downside of silica gel it s expensive
It s a moisture absorber but not as fast as calciumchloride it can hold some water but not as much as calcium chloride

The good thing is it does not form a crust it can easily be regenerated in an gas oven ( no electricity)

calcium chloride can hold on to a lot of water
But it can hold on to so much it becomes a liquid brine
It s cheap
It s hard to regenerate since it will clump
And I dare say I am assuming it a less dangerous if contamination happens on the flower ( debatable)

So then once the disincentive is chosen there are some questions regarding parameters
I have done r and d in the following manners

Pull a vacuum on loaded vessel

Pull a vacuum on loaded vessel and backfill with argon or nitrogen to atmosferisch pressure

Pull a vacuum and backfill to a low vacuum

Contemplating on backfilling to 15psi to highten boiling point of terpenes but this is a thingy will flower still dry ??

Now all backfill options worked even better when some circulation took place by means of a vacuum pump with it a exhaust pushing back in the same vessel treu the disicant
But calcium chloride makes a crust and thus inhibits it s surface area and motion needs to be applied once in a while to break this crust

Questions are
How do you calculate evaporation of water in inert gas atmosphere ?
Would you have your disincant in side the vessel or outside like a molecular sieve air dryier for compressors ?
At what temperature would you hold your vessel ?
All my trails where at 15C or -40C
Personally think 4C should work

At last I was wondering what vessel would you recommend to scale this

My options so far are

Vacuum vessel for drying wood
Sawdust drier
Vacuumtumbler
Pressurized vessel if I can figure out if flowers will dry wich technically should be possible if the circulating gas/air is dry enough

I would do more r and d if it was not an issue to find fresh flowers this time of year and want to implement this coming harvest so I need to decide now

Thx as always

4 Likes
2

Interesting idea.

Good question. Probably conceptually similar to heat transfer, only for humidity.

I think outside should work just as well as inside, as long as you’re circulating the atmosphere around.

I think I could make a pretty coherent argument for any of those to be honest, but I think above freezing is probably the lowest probability of it causing problems. 4 is a nice number.

Something with positive pressure. You probably don’t need much if any - a bar is probably way overkill.

2 Likes
3

Why ? Just for the sake of making terpene boiling points higher ?

It will help in keeping the system innert at all times but since leaks in a. Vacuum system are hard to catch

1 Like
4

seems like calcium chloride can be used as desiccant in the liquid phase…which might get you around the caking issue.

as far as calculating how it is gonna work up front, you’re asking the wrong guy. I guess and iterate. I’ve gotten good at guessing over the years, but I’ve got no clue on this one.

it does seem like using liquid phase desiccant is worth exploring

3 Likes
5

Using dry nitrogen along with calcium chloride can work synergistically to enhance drying while preserving volatile compounds like terpenes. The nitrogen helps reduce oxygen (preventing oxidation), absorbs minimal moisture itself, and can increase system pressure, which—via Henry’s Law—helps keep volatile terpenes dissolved in the plant matrix, reducing their evaporation.

Long explanation:

You’re working with two overlapping but complementary systems:

  1. Calcium Chloride as a Desiccant

Mechanism: Calcium chloride is hygroscopic; it absorbs water vapor from the surrounding air and binds it into a brine or solid hydrate.

Use: This lowers the relative humidity (RH) of the chamber, promoting moisture evaporation from your plant material.

Limitation: If the desiccant is saturated or the environment is very humid, its performance will be reduced over time.

  1. Dry Nitrogen Gas

Purpose: Dry Nâ‚‚ can serve multiple roles:

Inert atmosphere: Prevents oxidation and terpene degradation.

Carrier gas: Helps sweep away water vapor if flowing.

Pressurization agent: If used in a sealed system, increasing the pressure can help retain terpenes.

Applying Henry’s Law

Henry’s Law says:

C = kP
Where:

C is the concentration of the gas dissolved in a liquid/solid matrix,

k is Henry’s constant (depends on temperature and solute-solvent pair),

P is the partial pressure of the gas.

For terpenes, which are volatile organics, the “gas” phase represents the escaping vapor, and “liquid” or “solid” represents the plant material.

By increasing system pressure, especially with an inert gas like nitrogen:

The equilibrium shifts to favor retention of volatile compounds.

Higher pressure means the escaping tendency of terpenes is reduced—they stay dissolved in or adsorbed onto the plant tissue.

You may see less aroma loss and better preservation of flavor profiles.

Key Considerations

Drying Rate

The drying rate will still be driven by vapor pressure gradients and relative humidity.

Adding nitrogen can reduce the partial pressure of water vapor (if flowing or dry) and assist drying.

If the nitrogen is static and dry, it won’t remove water but can still affect partial pressure distribution.

System Pressure

You’ll need to control pressure carefully. Too high and you risk reducing drying efficiency.

Ideal might be a slight overpressure (1.1 to 1.5 atm) to balance terpene retention and water removal.

Temperature

Lower temperatures slow terpene volatilization but also slow drying.

Pairing mild heat (e.g., 25–35°C) with desiccant and slight nitrogen pressure might offer the best compromise.

Summary

Your idea is scientifically valid. A combined system of:

Calcium chloride (to absorb water)

Dry nitrogen (to create an oxygen-free, pressure-stabilized environment)

…can help dry plant biomass gently and efficiently, while preserving terpenes due to pressure-based suppression of volatilization.

If you have a sealed chamber, consider using a slightly pressurized, recirculated nitrogen atmosphere with continuous or batch desiccant cycling to maintain low humidity.

3 Likes
6

Yes

I’ve done that. Works well as a saturated brine if you overkill it. Haven’t tried non-overkill applications.

1 Like
7

You see this is why I love this place
Thank you to all
As for vessel since pressure seems the way to go I guess an autoclave is the way to go.
Steel body stainless steel carts for flowers or kief
Secondhand seems within budget

Calciumchloride seems to be the the prefured choice
Now as for wich pump to use for the recirculating of inert gas I have

A few options but might as well ask
Since now we are considering pressure
Whatpump for circulating the moist inert gas ??

At first my intention was an ebara aa70 WN V1
Dry vacuum vacuum pump

I then tought a normal in-line (duct) ventilator gas tight ofcourse

And I have a blower sidechannel blower 5.5 kw /vacuumpump

Not sure how the pumps will respond to pressure
At intake and exhaust

So nice not to have to worry about atex :face_blowing_a_kiss:

3 Likes
8

I’d go with something like this. Commonly identified as a vacuum ring blower. They don’t produce a massive differential pressure, but it seems like it would work well for making gasses spin in a circle.

71tDJsj5l6L.AC_UF894,1000_QL80
71tDJsj5l6L.AC_UF894,1000_QL80894Ă—984 100 KB

I’d also not bother with an autoclave. If I had to guess, you’re probably not going to see much of a benefit over 0.5 bar of positive pressure. Maybe even 0.1 or 0.2.

Make it stainless, make sure there aren’t any holes, let er rip.

Triclamp kegs would probably work well enough.

Of course, it’s also possible that I’m wrong and pressure is actually harmful for some reason.

3 Likes
9

Ah great that’s what I cal a side channel blower vacuum pump

Ok maybe the scale is not clear but I want to be able to dry amounts in the 1000kg > range

So what would it take to have a 40’ reefer container
Gas tight doors ??
Are there any of the shelf options for making containers gas tight ???

10

Welder and big sheets of stainless or aluminum? Seems like an expensive and failure prone headache.

I’d be looking for a big ex winery, brewery, or dairy tank if it were me, but I don’t know if such things are commonly available around you. Doesn’t need to be stainless, really. Plastic would probably also work at lower pressures.

3 Likes