yep, with that starting point (hash), the color is not unexpected. the temps you are recovering solvent and decarbing at are not doing you any favors, but the primary issue is definitely your starting material.
non-polar solvent or distillation of your cannabinoids probably you best bets. crashing the THCA out might be an option, but the decarb level on your starting material is likely all over the map, which would make that approach unreliable.
The only way youre going to get reliable results will be sourcing fresh material. Preferably something that has been stored cold if that is not an option. The major cause of red coloration is oxidation as opposed to the others you mentioned. With ethanol alone theres not much you can do here that I have ever been able to find.
That said - a quick trick would be to try decarbing in your roto under vacuum to limit the oxygen available when heating (which increases process oxidation significantly). This wont undo the existing oxidation, but does significantly limit further oxidation compared to a hot plate.
If your process requires old material, might pivot to a different product line than vapes. EHO vapes can be challenging as is without that being a factor.
I will keep in mind for future reference to attempt to use more lightly colored and fresher hashes if possible.
Regarding operating temperatures:
Would I be better off minimizing solvent recovery temperature, perhaps closer to room temperature?
And regarding decarbing, I was of the impression that the optimal end temp should be 140c(284f) in the oil bath when decarbing with a rotovap. Do you believe there is a big difference from say 120c(248f) for 20-25 min vs immediate removal of evaporation flask once it reaches 140c(284f)?
Fresh material. Noted. Thanks. I will attempt in the future to acquire fresher material.
I do decarb under a vacuum in a rotovap to limit muffin/bubbling, never thought about the minimization of oxidation, thanks for the input, I will continue decarbing by this method.
For the time being the market here is far from saturated with high-quality vapes, so thankfully it is not an issue at this point.
I read somewhere that activated carbon>W1>activated alumina>D.E.
is a good one. I forget the ratio of powders to material though.
Not sure how well it works. I only do activated charcoal and D.E. for my etoh clean-ups but I’ve hit red before too.
Suggested to me was always the AA or W-1 but I never used them or tried it.
Bentonite clay will work better with ethanol if it’s cold. I only got to -30 when I did but it did a good job at keeping color out when distilling. If you can get really cold (-80) I’d say test it out by filtering through cold bentonite plug and see what happens.
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 here…
Only EHO from hashish
Ahh thanks!
Attempted filtering at -30c (-22f) starting point for Büchner funnel and EtOH solution.
The difference blew my mind.
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 Büchner 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 Büchner 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? 
I’m referring to C. Do make sure that you aren’t losing too much to your filter media so wash your media with more cold ethanol; it shouldn’t be an issue but it’s a mistake I’ve 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). It’s very hard to get yellow out of ethanol extracts, especially if you aren’t 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!
Also, if you are having a hard time keeping your entire setup cold enough, you could do whats called a ‘scrub’ where you take your tincture and add an amount of bentonite to it and stir it at-30 for a period of time (you’ll 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 haven’t 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 there’s wax still if your solution gets cloudy once cold, implying flocculation of wax particles.
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 Büchner 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.
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 captured…
Please share your limits / concerns / variables that may limit your options.
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 doesn’t make economical sense to purchase much more equipment.
As it stands now, I am extremely happy with the results, based on what I’ve seen so far, and don’t 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.
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?
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.
The equipment I have now:
-40c freezer, Büchner 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 20µm, 12µm, 7µm, 2µm and 0.22µm)
Activated carbon, bentonite clay, diatomaceous earth, PVPP
My updated method:
