Best method of extraction for preserving flavour & smell?

Hello everyone,

I've been lurking around the forums for a while now and decided it's time to make my first post. I would have liked it to be a grow journal, but unfortunately I am without access to my laptop right now.

So instead, I hoped I could spark on a discussion on preserving the volatile terpenes in cannabis concentrates.

It's my understanding that many of these terpenes leech out into the water in the process of making bubble hash, so this is no good (correct me if I'm wrong, please!).

I'm a bit of a new comer to organic chemistry so I'm not entirely sure why the terpenes would be removed from the makeup of the oil in a butane or ethanol extraction. I presume its down to oxidation and degradation after the trichomes dissolve and release these compounds into the solution but that's just a guess.

So the two options that spring to mind are: super critical CO2 extractions and finding a more suitable solvent with a lower boiling point.

While super critical CO2 extractions seem ideal, it isn't really feasible for the home chemist.

What I was thinking of is rigging up a soxhlet extraction of the material using chloroform. The relatively low boiling point makes this solvent very easy to evaporate off so most of the terpenes should remain in the solution of oils. We would then use a rotovap to evaporate off the solvent under vacuum (chloroform boils at 24.1 degrees celsius under 200 mmHg of vacuum). The resulting product should be chock full of terpenes, right?

This is all just theory and speculation so I'd be very happy to hear what other people have to say on this matter (just don't comment about chloroform being toxic and harmful, I know this! I'm looking for the best method, not the safest, so far chloroform looks to be one of the most suitable solvents. I guess dichloromethane could be substituted in here, too.)

Thanks for reading, looking forward to what you all have to say.

glasgrowers1 said:

Hello everyone,

I've been lurking around the forums for a while now and decided it's time to make my first post. I would have liked it to be a grow journal, but unfortunately I am without access to my laptop right now.

So instead, I hoped I could spark on a discussion on preserving the volatile terpenes in cannabis concentrates.

It's my understanding that many of these terpenes leech out into the water in the process of making bubble hash, so this is no good (correct me if I'm wrong, please!).

I'm a bit of a new comer to organic chemistry so I'm not entirely sure why the terpenes would be removed from the makeup of the oil in a butane or ethanol extraction. I presume its down to oxidation and degradation after the trichomes dissolve and release these compounds into the solution but that's just a guess.

So the two options that spring to mind are: super critical CO2 extractions and finding a more suitable solvent with a lower boiling point.

While super critical CO2 extractions seem ideal, it isn't really feasible for the home chemist.

What I was thinking of is rigging up a soxhlet extraction of the material using chloroform. The relatively low boiling point makes this solvent very easy to evaporate off so most of the terpenes should remain in the solution of oils. We would then use a rotovap to evaporate off the solvent under vacuum (chloroform boils at 24.1 degrees celsius under 200 mmHg of vacuum). The resulting product should be chock full of terpenes, right?

This is all just theory and speculation so I'd be very happy to hear what other people have to say on this matter (just don't comment about chloroform being toxic and harmful, I know this! I'm looking for the best method, not the safest, so far chloroform looks to be one of the most suitable solvents. I guess dichloromethane could be substituted in here, too.)

Thanks for reading, looking forward to what you all have to say.

Click to expand...

Extracting terpenes is easy, retaining them while purging the solvent is harder.

The monoterpenes are alcohols, ethers, aldehydes, ketones, esters, and carboxylic acids with a high vapor pressure and try to leave with the solvent, even below their boiling points.

Why are you thinking that removing a 61.C/142.2F solvent would be easier than one like butane that boils at -.5C/31.5F?

We produce an extract that smells and tastes like what it was extracted from using butane

Dry sieve. Peace GS

Gray Wolf said:

Extracting terpenes is easy, retaining them while purging the solvent is harder.

The monoterpenes are alcohols, ethers, aldehydes, ketones, esters, and carboxylic acids with a high vapor pressure and try to leave with the solvent, even below their boiling points.

Why are you thinking that removing a 61.C/142.2F solvent would be easier than one like butane that boils at -.5C/31.5F?

We produce an extract that smells and tastes like what it was extracted from using butane

​

Click to expand...

And how to keep it when I purged in my vacuum oven. I always do like I may wrongly understood. Using 115 F and full vac until bubble chase stops and then flip it and do the same. But like this in less then 5 hours is ready. So is it safe to use ? Am I doing it correctly ? Thanks.

Leonleon08 said:

And how to keep it when I purged in my vacuum oven. I always do like I may wrongly understood. Using 115 F and full vac until bubble chase stops and then flip it and do the same. But like this in less then 5 hours is ready. So is it safe to use ? Am I doing it correctly ? Thanks.

Click to expand...

I just did a little bit, and at 115F at full vac, I found no odor of ethanol at the same time it quit muffling up, I could back the vacuum off half an inch of HG and found nearly zero reaction going on there. Going on for hours past that point seems overkill to me, but if you've lab tests to beat of whatever, feel free...

What is QWBHO with the coldest temps you can afford?

Why not make rosin?

^^^ rosin

I would love to have the test but I didn't yet. How Tro you stop half inch before ? Do you seal the valve for the vac ? Or just manually? And plus I tried like you explained in other post at 29.5Hg (I did it manual) and it's seems work great only issues after I've the shatter I can't really make it come out batter consistency. Any idea ? Any tips?

Leonleon08 said:

And how to keep it when I purged in my vacuum oven. I always do like I may wrongly understood. Using 115 F and full vac until bubble chase stops and then flip it and do the same. But like this in less then 5 hours is ready. So is it safe to use ? Am I doing it correctly ? Thanks.

Click to expand...

We are typically under 10% of FDA residual solvent standards in four hours, starting with cotton candy.

Gray Wolf said:

We are typically under 10% of FDA residual solvent standards in four hours, starting with cotton candy.

Click to expand...

Thanks GW it's hard now for me to cotton candy method but I will try I'm a rookie. So I extract from a pressurized closed column and then follow your method at 115F -29.5HG until stop chase bubbling and then flip it and do the same. Found my shatter to dab really tasteful but I never had opportunity to do a test and with let's say around 10 grams to 20 of concentrates this purging process takes me around 4/5 hours. My question is what do you think are my residues of butane possibly be ? And it would be safe to dab it ? And last how do I achieve budder/batter consistency without loosing terpenes but let it smell strong ? Thanks any tips or criticism is open to everyone.

I think its tough for someone to give you a recipe on how it works, cause it just doesnt work like that. Each concentrate has its own cannabinoids and those dictate how to handle your product.

If your purging at temps above 115 for 4 hrs and see little reaction coming from the oil you should be under the residual limit, but with that being said rushing with high temps isnt the way you wanna go to preserve terps. Low heat for a few days a full vacuum is your best bet. If your really nervous purge until theres 100% no reaction. You will loose terps but will be safe to dab forsure.

As far as cake batter consistency, after your done purging put oil on low heat (120 degrees ish) and whip it until the color lightens up then let sit for a few hours and it will "cake" up.

Hope that helps!

Gray Wolf said:

We are typically under 10% of FDA residual solvent standards in four hours, starting with cotton candy.

Click to expand...

jmewsk said:

I think its tough for someone to give you a recipe on how it works, cause it just doesnt work like that. Each concentrate has its own cannabinoids and those dictate how to handle your product.

If your purging at temps above 115 for 4 hrs and see little reaction coming from the oil you should be under the residual limit, but with that being said rushing with high temps isnt the way you wanna go to preserve terps. Low heat for a few days a full vacuum is your best bet. If your really nervous purge until theres 100% no reaction. You will loose terps but will be safe to dab forsure.

As far as cake batter consistency, after your done purging put oil on low heat (120 degrees ish) and whip it until the color lightens up then let sit for a few hours and it will "cake" up.

Hope that helps!

Click to expand...

Thanks a lot. My intentions are not to rush but to try to do the best that I can do. So i thought that I can go around 89/90 F for a ew days. But do I've to leave the vac on ? And do I get my batter consistency as well after the purge same method ? Thanks I don't know if you know them but I would like to do something like thelabcolorado.com they do with the batter.

Leonleon08 said:

Thanks GW it's hard now for me to cotton candy method but I will try I'm a rookie. So I extract from a pressurized closed column and then follow your method at 115F -29.5HG until stop chase bubbling and then flip it and do the same. Found my shatter to dab really tasteful but I never had opportunity to do a test and with let's say around 10 grams to 20 of concentrates this purging process takes me around 4/5 hours. My question is what do you think are my residues of butane possibly be ? And it would be safe to dab it ? And last how do I achieve budder/batter consistency without loosing terpenes but let it smell strong ? Thanks any tips or criticism is open to everyone.

Click to expand...

The FDA standard for Class III solvents is:

Solvents in Class 3 (Table 3) may be regarded as less toxic and of lower risk to human health.

Class 3 includes no solvent known as a human health hazard at levels normally accepted in pharmaceuticals. However, there are no long-term toxicity or carcinogenicity studies for many of the solvents in Class 3.

Available data indicate that they are less toxic in acute or short-term studies and negative in genotoxicity studies. It is considered that amounts of these residual solvents of 50 mg per day or less (corresponding to 5,000 ppm or 0.5 percent under Option 1) would be acceptable without justification.

Higher amounts may also be acceptable provided they are realistic in relation to manufacturing capability and good manufacturing practice (GMP).

Typically one order of magnitude lower, or 10% of maximum, would be set as an upper limit, or 500 ppm, though some localities use two orders of magnitude, or 50 ppm.

That is my long way of telling you that the FDA believes 50 mg per day or less are acceptable, sooooo odds are good that your sample is safe to consume.

Compare that to OSHA's exposure standard for workers of 800 ppm over 8 hours, and you have a better idea of how toxic butane actually is. https://www.cdc.gov/niosh/docs/81-123/pdfs/0068.pdf

That beings us to flavor, and human threshold for hydrocarbons is in the low PPM to PPB levels, soooo while it won't kill ya, it imparts an unpleasant tastes.

^ You're saying the state cannabis concentrate residual solvent standards are based on inhaling an undiluted dab? Pure vapor, no air? Chokes me up...

Nice document, first time I've seen it, thanks!

"Rational for limits: The limits are based on drowsiness and the risk of narcosis associated with exposure to n-butane." Period, read it and put it into context for yourself.

https://www.cdc.gov/niosh/docs/81-123/pdfs/0068.pdf




Gray Wolf said:

The FDA standard for Class III solvents is:

Solvents in Class 3 (Table 3) may be regarded as less toxic and of lower risk to human health.

Class 3 includes no solvent known as a human health hazard at levels normally accepted in pharmaceuticals. However, there are no long-term toxicity or carcinogenicity studies for many of the solvents in Class 3.

Available data indicate that they are less toxic in acute or short-term studies and negative in genotoxicity studies. It is considered that amounts of these residual solvents of 50 mg per day or less (corresponding to 5,000 ppm or 0.5 percent under Option 1) would be acceptable without justification.

Higher amounts may also be acceptable provided they are realistic in relation to manufacturing capability and good manufacturing practice (GMP).

Typically one order of magnitude lower, or 10% of maximum, would be set as an upper limit, or 500 ppm, though some localities use two orders of magnitude, or 50 ppm.

That is my long way of telling you that the FDA believes 50 mg per day or less are acceptable, sooooo odds are good that your sample is safe to consume.

Compare that to OSHA's exposure standard for workers of 800 ppm over 8 hours, and you have a better idea of how toxic butane actually is. https://www.cdc.gov/niosh/docs/81-123/pdfs/0068.pdf

That beings us to flavor, and human threshold for hydrocarbons is in the low PPM to PPB levels, soooo while it won't kill ya, it imparts an unpleasant tastes.

Click to expand...

Go figure, butane is now GRAS (Generally Recognized As Safe)

"Generally recognized as safe (GRAS) is an American Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts"

https://en.wikipedia.org/wiki/Generally_recognized_as_safe

"[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2016]
[CITE: 21CFR184.1165]



TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION
DEPARTMENT OF HEALTH AND HUMAN SERVICES
SUBCHAPTER B--FOOD FOR HUMAN CONSUMPTION (CONTINUED)
PART 184 -- DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE

Subpart B--Listing of Specific Substances Affirmed as GRAS

Sec. 184.1165 n-Butane and iso-butane.
(a) n-Butane and iso-butane (empirical formula C4H10, CAS Reg. Nos. 106-97-8 and 75-28-5, respectively) are colorless, flammable gases at normal temperatures and pressures. They are easily liquefied under pressure at room temperature and are stored and shipped in the liquid state. The butanes are obtained from natural gas by fractionation following absorption in oil, adsorption to surface-active agents, or refrigeration.

(b) The ingredients must be of a purity suitable for their intended use.

(c) In accordance with 184.1(b)(1), these ingredients are used in food with no limitations other than current good manufacturing practice. The affirmation of these ingredients as generally recognized as safe (GRAS) as direct human food ingredients is based upon the following current good manufacturing practice conditions of use:

(1) The ingredients are used as propellants, aerating agents, and gases as defined in 170.3(o)(25) of this chapter.

(2) The ingredients are used in food at levels not to exceed current good manufacturing practice.

(d) Prior sanctions for these ingredients different from the uses established in this section do not exist or have been waived."

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=184.1165




"Food and Drug Administration, HHS

§ 184.1165 n-Butane and iso-butane.

(a) n-Butane and iso-butane (empirical formula C4H10, CAS Reg. Nos. 106– 97–8 and 75–28–5, respectively) are colorless, flammable gases at normal temperatures and pressures. They are easily liquefied under pressure at room temperature and are stored and shipped in the liquid state. The butanes are obtained from natural gas by fractionation following absorption in oil, adsorption to surface-active agents, or refrigeration.
(b) The ingredients must be of a purity suitable for their intended use.
(c) In accordance with §184.1(b)(1), these ingredients are used in food with no limitations other than current good manufacturing practice. The affirmation of these ingredients as generally recognized as safe (GRAS) as direct human food ingredients is based upon the following current good manufacturing practice conditions of use:
(1) The ingredients are used as propellants, aerating agents, and gases as defined in § 170.3(o)(25) of this chapter.
(2) The ingredients are used in food at levels not to exceed current good manufacturing practice.
(d) Prior sanctions for these ingredients different from the uses established in this section do not exist or have been waived.

[48 FR 57270, Dec. 29, 1983, as amended at 73 FR 8607, Feb. 14, 2008; 76 FR 59249, Sept. 26, 2011]"

https://www.gpo.gov/fdsys/pkg/CFR-2014-title21-vol3/pdf/CFR-2014-title21-vol3-sec184-1165.pdf



^ That's the 2014 version, notice the difference in the same section from 2012,



"Food and Drug Administration, HHS

(2) The ingredient is used in food at levels not to exceed current good manufacturing practice. Current good manufacturing practice results in no significant residue in foods.
(d) Prior sanctions for this ingredient different from the uses established in this section do not exist or have been waived.

[47 FR 43367, Oct. 1, 1982, as amended at 73 FR 8606, Feb. 14, 2008; 76 FR 59249, Sept. 26, 2011]"

https://www.gpo.gov/fdsys/pkg/CFR-2012-title21-vol3/pdf/CFR-2012-title21-vol3-sec184-1165.pdf



They removed the qualification statement concerning "significant residue in foods" because it was declared GRAS.



Butane ppm residual standards are unnecessary to protect anyone's health.

I want to make "Butane is GRAS" t-shirts.

^ "Butane is GRAS, why isn't grass?"

http://www.anandaapothecary.com/aro...7/essential-oils-generally-recognized-as.html


"Is Marijuana, or THC, a GRAS (Generally Recognized as Safe) Food Additive?

Now we come to a question that seems to have been ignored. Is THC a GRAS substance? The process for gathering data and submitting a petition for GRAS status is long and expensive. Should not marijuana or THC be deemed GRAS before it is used in foods and beverages? At the moment, it does not appear to have been deemed GRAS. The U.S. Food and Drug Administration has established programs to accelerate the process for submitting and evaluating applications for GRAS status. However, since the federal government has washed its hands of enforcing drug laws pertaining to marijuana at the state level, it would probably punt on reviewing a GRAS status submission for THC and/or marijuana.

This may end up being a mistake in the long run. Companies have spent piles of money and much time to submit applications. Allowing such a compound to be used in foods without an official evaluation may raise eyebrows throughout the industry.

So the question remains as to whether marijuana or its derivatives are indeed GRAS substances."

http://www.foodsafetymagazine.com/m...er-2015/the-cannabis-conundrum-is-grass-gras/



So, if no butane residual standard is necessary, does that mean we're going to have flaming dabs!??

Take a simple butane lighter (not torch,) and try igniting it with your e-nail instead of the flint, I tried up to 800F, and nothing.

The infinitesimal bit of butane residual from a dab enters your lungs as safe, unburned, tasteless, and odorless (at that dilution with air) butane.


Btw, while reflecting on butane catching on fire from the heat of an e-nail, I tried something simple, and was surprised at the flashy response, hold a simple butane lighter's (not torch) flame just above your e-nail (about a half inch works very nicely,) without inhaling through the rig, apply a dab to the e-nail. The vapor will rise, and burst into flame when it reaches the lighter's flame. Notice the flame doesn't die down, even if you remove the lighter flame, until all the oil is gone. I did my experiment at 666F.

"Flash points are determined by slowly heating up an oil one degree at a time until a temperature is reached where a flash of fire results when a wand with a tiny flame at the tip is waved over the surface of the heated oil. What this procedure determines is the temperature of vaporization of the most volatile compounds of the oil."

The Chemistry of Essential Oils Made Simple: God's Love Expressed in Molecules by David Stewart, Ph.D., D.N.M., page 432.

I experimented with this further at temps from 400F to 600F, at 400F the vapor barely lit and went out, as I tried it again and again at higher temps, the period it stayed lit increased, leaving less and less puddle behind, finally at 578F it flamed unassisted all the way to the end of the puddle.

Thread: "Ideal Flash Vaporization Temperatures (and ways to achieve them)" by SkyHighLer,

http://www.tokecity.com/forums/show...zation-Temperatures-(and-ways-to-achieve-them)

Rosin is the best preserver of smell and flavor imho.

Gray Wolf said:

The FDA standard for Class III solvents is:

Solvents in Class 3 (Table 3) may be regarded as less toxic and of lower risk to human health.

Class 3 includes no solvent known as a human health hazard at levels normally accepted in pharmaceuticals. However, there are no long-term toxicity or carcinogenicity studies for many of the solvents in Class 3.

Available data indicate that they are less toxic in acute or short-term studies and negative in genotoxicity studies. It is considered that amounts of these residual solvents of 50 mg per day or less (corresponding to 5,000 ppm or 0.5 percent under Option 1) would be acceptable without justification.

Higher amounts may also be acceptable provided they are realistic in relation to manufacturing capability and good manufacturing practice (GMP).

Typically one order of magnitude lower, or 10% of maximum, would be set as an upper limit, or 500 ppm, though some localities use two orders of magnitude, or 50 ppm.

That is my long way of telling you that the FDA believes 50 mg per day or less are acceptable, sooooo odds are good that your sample is safe to consume.

Compare that to OSHA's exposure standard for workers of 800 ppm over 8 hours, and you have a better idea of how toxic butane actually is. https://www.cdc.gov/niosh/docs/81-123/pdfs/0068.pdf

That beings us to flavor, and human threshold for hydrocarbons is in the low PPM to PPB levels, soooo while it won't kill ya, it imparts an unpleasant tastes.

Click to expand...

I found a comprehensive review of the studies this morning,

http://www.tceq.texas.gov/assets/public/implementation/tox/dsd/final/butanes.pdf