Interesting, I will try to attempt a re-run of filtration with bentonite at around -25c to -40c (as cold as I can get).
Are the temperatures you are referring to Celcius or Fahrenheit?
Does the clay change the PH of the distillate do you know?
There is no distillate being discussed hereâŠ
Only EHO from hashish
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Ahh thanks!
Attempted filtering at -30c (-22f) starting point for BĂŒchner funnel and EtOH solution.
The difference blew my mind.
The glass on the left is room-temp filtration.
The glass on the right is -30c filtration.
As I was unsure how to stack the activated carbon and bentonite clay, I sandwiched the bentonite between AC.
In a 110mm (4-5") buchner I stacked 25g (0.9oz) AC > 50g (1.8oz) bentonite > 25g (0.9oz) AC.
From my previous calculations, this should be enough for 5L (1.3gal) of EtOH solution.
The filtration was a lot slower when done cold. Took about 10 times longer than at room temperature (if not more). The liquid poured out at around 6 minutes per deciliter (2 minutes per fl. oz.).
Within about one hour of continuous filtration, I noticed that the filtrate was starting to become red again (the sample to the right in the picture was taken in the early stages of filtration before the red came back), I assume this happened due to the BĂŒchner funnel, filter media and liquid getting warmer, rather than the filter media becoming saturated, as at this point I had only filtered approximately 1 liter (0.25 gal) of liquid.
Due to the slow filtration because of the colder temperatures, the BĂŒchner funnel gets warm eventually, and freshly poured liquid at -30c (-22f) quickly raises to -8c (17.6f) before completing the filtration. I assume this is the reason the red is coming back.
I am therefore going to retrofit the filtration setup in a freezer so that the temperature never rises above -25c (-10f), and attempt a complete filtration.
I guess the next question would be⊠is it possible to remediate the yellows? 
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Iâm referring to C. Do make sure that you arenât losing too much to your filter media so wash your media with more cold ethanol; it shouldnât be an issue but itâs a mistake Iâve made before.
Not sure how to get the yellow out completely though, if you could get colder it may help (get some dry ice or liquid nitrogen, though you will go through a lot of it). Itâs very hard to get yellow out of ethanol extracts, especially if you arenât using hydrocarbon solvents.
Recovering solvent at a lower temp can help, but you will also have an issue with color as you decarb since ethanol extracts tend to discolor with increasing temperature. If your color is still unsatisfactory after decarbing the one on the right, perhaps consider a decarb catalyst if you feel so bold.
Glad the cold filtration worked though. Keep working at it!
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Also, if you are having a hard time keeping your entire setup cold enough, you could do whats called a âscrubâ where you take your tincture and add an amount of bentonite to it and stir it at-30 for a period of time (youâll have to find times and amounts yourself). Then you filter through a filter cake like diatomaceous earth to remove fine bentonite particulate. This is a good technique is you lack the infrastructure to keep an entire filtration apparatus cold.
If you havenât dewaxed your solution yet, that could be causing slow filtration issues as the wax particles are fouling your filter cake and restricting flow. If this step is acting as a dewax step for you as well filtering cold is likely better than scrubbing as you will want to remove the wax as well. You can tell if thereâs wax still if your solution gets cloudy once cold, implying flocculation of wax particles.
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I let the filter media soak in ethanol for 20min before making the cake. Then filter about 1 liter of pure ethanol through the cake. I then put the BĂŒchner with filter cake into the freezer until the desired temperature is reached.
I will be testing out yields and doing calculations to see what loss there might be.
I am very happy with the result so far and was slightly joking when mentioning remediating the remaining yellows. Thanks a lot for the input, it has been very helpful! Very excited to see the difference in end result.
The filtrate has been winterized/dewaxed several times until no more visible wax forms on the filter paper. I assume it is >99% dewaxed. Appreciate the tip regarding cloudy once cold.
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Do you have access to room temperature solvents that defat well? The more you do the more you clean up. Chroma? Crc?
I read ethanol and freezers.
Can you consider options outside of readily available work solvents (ethanol)
Help me measure the limits of your pursuit. Because you can keep going.
Methanol seems to be the room temp king for defatting. Silica+crcstack and chromatography has shown me all colors capturedâŠ
Please share your limits / concerns / variables that may limit your options.
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I do not have immediate access to many other solvents in large quantities. I am also very happy using ethanol as it is one of the safest solvents at my disposal.
I enjoy not having to wear a solvent-filter/mask more often than necessary while working, which I can avoid most of the time working with ethanol. Methanol on the other hand has very harmful vapors.
Also, my clientele prefers discolored carts rather than using possibly harmful solvents, which is why I am attempting color remediation without changing solvent.
This is a new world to me that I have only been learning about for the past months, I am very much a noob. I have therefore not delved into the process of Chroma or using CRCs, I assume it is a relatively pricy upgrade for me. At this point in time, it doesnât make economical sense to purchase much more equipment.
As it stands now, I am extremely happy with the results, based on what Iâve seen so far, and donât see the point of changing to different solvents and filtration setups or adding more processes at this time, in order to get beyond the current results. I am still very much open to hearing what you have to say if you have any input. Changing the filtration setup or adding different filtration media is much more realistic for me than changing solvents.
The freezer technically goes down to -40c, so it does work very well for winterization (which I assume is different from defatting?). I am however considering an upgrade to a ULT freezer that goes down to -86c - if that is of any help.
Thanks for your response so far. Much appreciated.
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So this tek would really bring down the cost of equipment for making carts. Your equipment list is: -40 freezer, buchner filter, bentonite clay, buchner filter, rotary evap?
Your method here is etoh bucket tek, bentonite clay filtering, rotary evap, add terps, load into carts?
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I dont want to be that guy but isnt this just winterization?
The gums and fats are bringing the color thru, so eliminating them shows better color, because the pigments dont have as much to stick to and its not suspended in the solution by being bound to a fat molecule.
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The equipment I have now:
-40c freezer, BĂŒchner funnel and filtration flasks, rotary evaporator, explosion-proof vacuum pump, magnetic stir-plate/hotplate, and additional minor equipment.
The filter media I have at my disposal:
Filter paper/membrane (approx 20”m, 12”m, 7”m, 2”m and 0.22”m)
Activated carbon, bentonite clay, diatomaceous earth, PVPP
My updated method:
- Dissolve hashish in ethanol
- Filter out large particles using 20”m filter paper.
- Cool bĂŒchner and filtrate down below -30c
- Winterize at 20”m then 12”m then 7”m (filtering separately, all at -30c)
At this point the 7”m filter paper does not retain any waxes anymore, I assume the winterization process is mostly complete. - Color remediation @ -30c (through a stack of bentonite clay and activated carbon, with a 12”m filter paper below).
- Filter at room temp through 2”m filter paper, then 0.22”m membrane filter to grab any final particulate from the hashish or the filter media.
- Solvent recovery and decarb in a rotary evaporator.
- Add terps and load into carts.
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Perhaps? I do 3 paper-filter passes at -30c to remove waxes before starting any filtration through activated carbon or bentonite clay. I was under the impression that the first 3 passes would complete the winterization process. The difference in color before and after winterization is minuscule, it is rather that the liquid loses its cloudiness. Are you saying that fats and gums pass through my winterization steps, and only get removed when filtering through AC/BC?
Please correct me if I am mistaken.
Something else that may help you is making a filter cake out of Celite aka diatomaceous earth to reduce the number of winterizations. Even though your filter paper micron size might me small enough, some particulate can make itâs way through over time.
Below is my fritted Buchner and I put a layer of celite for finer filtration. I also put a bunch of cotton balls on top to act as a depth filter to increase the surface area and so I could just replace it as it fouls.
Additionally, you can actually filter through a layer of bentonite on top or in between a layer of the celite (or filter paper) to decolor and winterize in one step. Since youâre already cold enough, you might as well (and the bentonite will act as a filter cake instead of celite). You can do the same with activated carbon but if your using it at low temps. If not, youâll need to do it separately.
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Iâm wondering why decarb if itâs going in a cart. Iâm just a diyâer and never decarbed it. Can someone explain please.
THCa can crystallize at pretty low concentrations of like 40-50% so for carts you usually have to do it at least partially to not clog it.
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Decarb lowers viscosity.
So you donât have to add diluent
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I use butane and then ethanol,winterize, into the turbo source and then use a vacuum chamber. Never had a issue with it being too thin except when it wasnât completely vacuumed out. But it will sometimes start plugging up the cartridge about halfway through. I was afraid the turbo source was too hot but it is at 105f
Are you sure you donât have viscosity backwards?
Water is low viscosity, honey is medium viscosity.
Decarb and diluent would both make âtoo thinâ worse.
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