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The reason NETs are so gunky and what I do to alleviate the problem

Discussion in 'Liquid Extraction From Tobacco' started by Str8vision, May 3, 2017.

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  1. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    I've been extracting flavor from tobacco and making NETs for years. NETs are notoriously hard on wicks and coils, they're "gunky". To be fair any natural extract that's used to flavor e-liquid (juice) will be gunky for the same reason NETs are. Regardless of what solvent and method of extraction is used, along with the desired "flavor" plenty of wax, oil, resin, sugars, chlorophyll and other undesirable constituents of the tobacco are inadvertently leeched into the extract. To be terse, I simply refer to these undesirable elements as "muck".

    When you vape NET the muck it contains doesn't completely vaporize. The PG, VG and most of the flavor molicules do but the majority of muck gets left behind, gathering in the wicking material. It saturates the wick and begins caramelizing on hot coils forming the thick, crusty, burnt coating (and taste) you're familiar with. Depending on a person's level of tolerance this can lead to re-wicking and dry-burning coils after just a single tankful (~3ml). The type of tobacco, how it was cured, casings, top notes and even the method/solvent used to extract it directly impact how gunky a NET will be. Many people have accepted the gunky nature of NET as being unavoidable and to an extent, they're right. NETs will never enjoy the same level of performance as a clear, unsweetened, synthetic flavored juice. Some people even go so far as inferring this muck is necessary in order for NETs to have a full tobacco flavor but in fact this isn't true. The muck is actually a flavor inhibiting, coil/wick trashing contaminant that contributes -nothing- beneficial. It's an unavoidable byproduct of the extraction process.

    Mechanical filtration removes any particles of tobacco and other debris from the extract helping to improve its performance. Unfortunately, mechanical filtration is of limited effectiveness in removing the extracted muck. This is because mechanical filtration is good at catching particulates (small particles suspended in the solution) but not good at removing compounds that are dissolved in the solution (solutes). In extracts the solutes (dissolved muck) and extraction solvent form a "homogeneous mixture" that will pass straight through even high retention absolute filters (<1 micron). The only way I've found to remove the muck (without also removing flavor) is by first changing it's state from a solute to a "precipitate" (a separated semi-solid), only then will mechanical filtering be effective at removing it.

    When using 190 proof Pure Grain Alcohol (ethanol) as the extraction solvent, a good portion of the muck can be removed through a "freeze filtering" process. This is accomplished by placing the sealed container of extract in a freezer for 72 hours, the colder the temperature, the more effective the process will be. Exposure to extreme cold causes a "precipitation" reaction to occur and over time a substancial portion of the muck will fall out of solution, changing from a solute (dissolved muck) into a "precipitate" (seperated semi-solid muck). As it falls out of solution the precipitate coalesces in the bottom of the container. After 72 hours (and while still in the freezer) the extract is filtered. Here's how much precipitate (muck) was removed from ~50ml of an ethanol based tobacco extract;

    Muck.png



    For larger batches of ethanol based extract, there's a more effective technique of purification available. It involves freeze filtering "reduced" extract. To reduce an ethanol based extract you simply evaporate a large portion of the ethanol off, the portion that remains is highly condensed. Once reduced the remaining condensed extract becomes oversaturated with solutes making the freeze filtering process even more productive. To illustrate how effective the purification process can be here's what coils and wick look like after vaping (dripping) ~10ml of NET made from highly purified extract;

    wick 2.jpg



    The most common extraction solvent used by DIY home extractors and retail NET vendors is Propylene Glycol (PG). Neither PG nor VG based extracts can be freeze filtered, however, out of necessity, I did find a way around this. I Mixed a well aged, highly filtered PG/VG based extract with an equal amount of 190 proof PGA (ethanol). I allowed this mixture to sit at room temperature for a day and then placed it in a freezer at -20F. After 72 hours (and while still in the freezer) the extract was filtered. Here's a pic of the muck removed from just 55ml of PG/VG based tobacco extract;

    PG sludge 3.jpg

    The 80/20 PG/VG extract had already been vacuum filtered through an absolute 1 micron borosilicate glass lab filter so what you see is what mechanical filtration alone couldn't catch without first adding ethanol and then freeze filtering the mixture. You're looking at "the muck" that makes NET so hard on wicks/coils. I don't suggest purifying PG/VG based extracts this way, there's no point since you could just use ethanol for the extraction solvent to start with. I developed this method because I have a lot of well aged PG/VG based extracts made from tobacco that is no longer sold/available. Since these extracts are irreplaceable I wanted to find a way to purify them. After freeze filtering was complete I simply evaporated the added ethanol off and re-filtered the extract through a 1 micron paper lab filter.
     
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  2. halbgott

    halbgott Senior Member ECF Veteran

    Apr 23, 2012
    That's a lot of work. Has anyone tried boiling a solution and collecting the steam like distilling?
     
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  3. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    In truth the extraction/purification process isn't where the work is, it's mainly just waiting. Waiting for the flavor to extract, waiting a day while it reduces, waiting 3 days while it's in the freezer. The amount of time you're actually involved "doing something" (like pouring it into a filter) is measured in minutes or seconds. From start to stop the amount of time I'm "hands-on" involved with a given extraction is probably 15 minutes of labor, but I've been doing this for a long time. When I extract a tobacco that I know I like, I now make enough from a single extraction to flavor a liter or more of NET. That way I should only need to extract that specific tobacco once every few years. The "work" comes when mixing the extract into NET, individually bottling and labeling it especially since I still hand label each bottle. This actually requires more hands-on time than the extraction process, maybe half an hour to 45 minutes for a liter. The effort that I do expend producing purified NET significantly reduces the need to re-wick and dry-burn, a task I find far more time consuming and tedious especially since I vape 8-10ml of NET a day. With regular NETs (like retail) I'd need to re-wick/dry burn around twice a day or about 700 time a year, Personally I think that would be a lot of work.

    At one time an online retail NET manufacturer (no longer available) made their NETs using steam distillation. The problem with steam distillation is the heat required for the process alters/damages the tobacco flavor making it taste "generic" much like a TA based NET but stronger, more robust. Their NETs did seem a little bit cleaner than those made by regular simple soak extraction methods but not by much. The temperature necessary to boil water (>210F) can be harmful to the tobacco flavor, cooks it. I've learned (the hard way) that tobacco flavor is actually quite delicate.

    Supercritical CO2 extraction produces an amazingly robust essential oil but what I've sampled also tasted generic like a TA based NET. It was considerably cleaner than simple soak or steam distilled NETs. I'd really enjoy playing around with the process to see what flavor potential it might have but the equipment is -cost prohibitive- for home extraction. I honestly believe it could produce outstanding high performance NET if someone with knowledge of tobacco extraction and NETs worked with it for awhile.
     
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  4. colonelcolt

    colonelcolt Full Member

    May 21, 2014
    London UK
    Thanks a lot for this post, very enlightening.
    I've got a question though...
    When you extract with PGA or add it to PG you would want to evaporate the PGA afterwards, right? So my concern is would not the ethanol take most/part/top notes of tobacco flavour with it?
    How you would approach this problem?

    Thanks
     
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  5. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    Most of it yes. After the flavor extraction and purification process is complete some people transfer the flavor from ethanol over to PG (or VG). Basically, this is done by adding PG to an ethanol extract, mix it well and then evaporate the ethanol off. Others just leave it as an ethanol based extract and use it like a concentrated flavoring. If that's the case the extract should first be reduced (concentrated) before use so that when you mix it with PG, VG and nic there's a minimal amount of ethanol in the mixed NET, usually around 7%. After mixing the NET some people vape it -as is- while others will allow the remaining ethanol to evaporate off first. Just a matter of personal preference.



    No at all. When you evaporate ethanol off the flavor it contains stays behind in the remaining extract, it just becomes more concentrated.
     
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  6. Burnie

    Burnie The Bug Man Verified Member ECF Veteran

    Jul 1, 2009
    Sunny Florida
    Here is Florida we can only get 151 proof, which is only 75% Pure Grain Alcohol (I am guessing the other 25% is water), would this not mess up the extract with that much water? (25% water in 151 proof over 5% water in 190 proof that you used)
     
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  7. mcclintock

    mcclintock Ultra Member ECF Veteran

    Oct 28, 2014
    As to a sort of measure of the normal gunk level, I have some of the last of MVJ's extracts, I would say the gunk level isn't so much worse than synthetics per % flavor, but they are considered less concentrated (lots of PG/VG) e.g. use 25-30% extract in the mix. If you can use them in a mix at lower levels they can be little problem -- which I far prefer with these anyway, the .5% or so in my hybrid mix makes it (how long does this stuff last? 73 ml left). Not saying this compares with what Str8vision is doing, just a useful benchmark and a reason not be afraid of NETs.
     
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  8. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    Your right, when it comes to drinking alcohol what's not ethyl alcohol (ethanol) is basically just water. The lower the "proof" the higher the water content. You can use 151 proof PGA to extract flavor from tobacco and it can be successfully freeze filtered. After a 75% reduction (when you concentrate the extract) all that would be left is water. You'd have a concentrated water based tobacco extract. Water based extract has -no- shelf life because mold, bacteria and other health hazards will readily grow in water, it also promotes oxidation. You'd just need to mix the extract into NET. PG and VG are bacteriostatic and have anti-fungal properties so once mixed the extract would be fine. PG and VG are both hygroscopic, they readily absorb water (even from the surrounding air) and once absorbed it's held in solution making it extremely difficult to remove. Your NET would have a 7 - 10% water content so you might consider increasing the VG ratio to offset water's low viscosity. Many people add water to NET as a flavor enhancer/thinner so this might actually be ideal for some.
     
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  9. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    I have PG based extracts that are over three years old and taste better now than when they were fresh. They've been stored in colored glass bottles that are kept in a cool, dark cabinet.

    Dianne made some wonderful extracts, it was a sad day when MVJ closed it's doors. I've not heard anything but I hope she's doing well.

    Hybrids are some of my favorite NETs. I've even added small amounts of extract to synthetic retail juice like Charlie Noble's Pistachio RY-4 and Tripoli. Good stuff.
     
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  10. yourgurnard

    yourgurnard Senior Member ECF Veteran

    Feb 3, 2015
    London
    Fantastic Thread from the Guv'nor!!!
    Just consider how gunky My NETs are:- cold PG steep, 'filtered' thru' a coffee filter & then an offcut of 5micron filter 'sock' (leftover from when I was filtering used cooking oil for diesel!!!...) in a syringe.
    Yep, I could 're-steep' the crap that I dry-burn off & sell it as an alternative to Inawera's DNB!!!....
    As the 190-proof ethanol way is impractical for Me in the UK (Our nanny gubblement prints 'PLEASE ENJOY RESPONSIBLY' warnings on BEER ffs!!!!!....) My 'Gunk Fight' has been restricted to concentrating on what Hardware works for My grubby NETs....
    I'm pretty happy with results since discovering squonking; more specifically, the Pico Squeeze with an FT 'Little 16' atop, twin vert. coils & mesh wicks. I've got 2 of these & I take 'em everywhere. I'm vaping approx. 1/2 a bottle of each one (so about 6ml.) a day & just rely on a burn-off of the wicks over the gas hob & a dry-burn of the coils either last thing at night or 1st thing in the morn. A lot of the burnt crud ends up syphoning back into the bottle & settling at the bottom so it's not coating coil/wick as it used to when I was using an Origen/Magma with deep wells.
    The 1st Squeeze was bought back in October & I'm still on the original coils that I put in then (wicks changed once...I burned holes in 'em trying to dry-burn with a fresh batt. Doh!....)
    Just thought I'd put this up as an encouragement for anyone who's into NETs but gets fed up with them trashing Their coils.........& can't/won't put in the effort Re. PGA extracting!!! :)
     
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  11. BrentMydland

    BrentMydland Super Member Verified Member ECF Veteran

    Dec 15, 2014
    SE US
    What are you using to evaporate off the ethanol? A vacuum chamber?
     
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  12. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    Usually just fan assisted open air evaporation. If I'm in a hurry I'll heat the NET to 150F in a convection oven.
     
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  13. Kickingthesticks

    Kickingthesticks Super Member Verified Member ECF Veteran

    May 6, 2016
    Just wondering how did you get the muck out after pulling the extraction from the freezer? And what kind of extraction method did you use with the 190 proof. Thanks
     
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  14. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    I don't pull it from the freezer. After 48 to 72 hours has elapsed, I run the extract through a coffee filter while it's still in the freezer. I even chill the filter and filtering apparatus before using it. As long as the extract remains extremely cold, the muck (precipitate) remains a semi-solid that is easily retained (separated) by the filter. If the extract is allowed to warm, a portion of the congealed muck will re-liquefy and pass through the filter.


    For ethanol, I use this method; Tobacco extraction using heated Ethanol
     
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  15. Kickingthesticks

    Kickingthesticks Super Member Verified Member ECF Veteran

    May 6, 2016
    K thanks very much!
     
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  16. Island Vapor

    Island Vapor Super Member Verified Member ECF Veteran

    Jan 15, 2011
    Bahamas/ Florida
    I have been doing my extracts with coffee filters and so tired of the gunk.I wanted to thank you for the information for the cleaner extracts.I have a few questions and any help would be much appreciated.

    Str8visionWhere did you get your Filtering Kit - Vacuum Pump with Gauge, Filter Paper, Filtration Flask and PGA
    Also I found the 1 micron filters but they were over $100 for 100 of them do you have a better place I can but all of this from?

    Also when you freeze your extracts is it in a chest freezer with no fan motors in it or a refrigerator freezer with a fan motor in it?Just curious about the air movement affecting the extracts
    Hope you are having a great weekend AJ
     
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  17. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    The average coffee filter has 30 to 50 microns retention. They're handy for separating tobacco from solvent after the extraction process is complete or removing muck during freeze filtering but are woefully inadequate for final filtration. You really need 3 microns or better to adequately remove the particulates from the extract.

    I custom fabricated my vacuum filtering apparatus but unless you have access to a machine shop this wouldn't be a viable approach. For anyone wanting an "inexpensive" vacuum filtering setup I'd recommend shopping for something like this; https://www.amazon.com/gp/product/B00CBL6XK2/ref=ox_sc_act_title_3?smid=A3UX55PWU62L52&psc=1 Be aware ethanol (pure grain alcohol) extracts do not require vacuum filtration, they will gravity flow through a high retention filter in a matter of minutes. PG extracts will also gravity flow through a high retention filter but can take up to a day to do so and the ambient temperature needs to be 70F or higher. VG extracts require vacuum filtration when using a high retention filter.


    First, you need to know what size (diameter) filters you need. Then you need to know what type of filter you want, I much prefer binder-less borosilicate glass microfiber filters. What size you'll need depends on the holder you're using. If you don't have a filter holder you can just pleat fold a large diameter paper filter for use in a common funnel, for that I'd search for a 12.5cm or larger diameter. I use a vintage "Busy Liz" aluminum canning funnel that has a threaded accessory ring on bottom that holds/seals a 5.5cm paper filter perfectly. I waited until I found 5.5cm filters on-sale (100 for $20) and bought enough to last my lifetime. Buying glass microfiber filters is difficult because prices range from cheap to ludicrous and the pricing structure is bizarre. I can buy 100 11cm 1 micron glass microfiber filters for $20 or I can buy 100 of the exact same filters in a smaller diameter (9cm) for $80 (four times more $$$), makes absolutely no sense at all. If I were currently shopping for a filter to use in a regular funnel (where I needed to pleat fold it) I'd look at something like this; https://www.amazon.com/gp/product/B006OCUCFG/ref=ox_sc_act_title_5?smid=ATVPDKIKX0DER&psc=1 11cm is a little smaller than what I'd like to use but 100 for $20 is dirt cheap for this type of filter. Problem is this price won't last long, a week from now these filters might be $125. For buying filters you just need to shop it out and when you find what you're looking for at the price you're willing to pay buy them right then.

    I'm able to buy 190 proof PGA (95% ethanol) at local liquor stores. Unfortunately, not everyone can.


    When freeze filtering, the extract is sealed air-tight inside canning jars so air movement (or lack of it) makes no difference at all. I have an upright industrial freezer that isn't frost-free. It does have a vacuum system that once the door is opened and closed pulls a vacuum to expel/remove the warm, moist air that was let in. One important note, freeze filtering (fractional freezing) only works on PGA extracts, it doesn't work on PG or VG.

    I hope I've been able to help and answered your questions, If you have others or need clarification just ask :)
     
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  18. Island Vapor

    Island Vapor Super Member Verified Member ECF Veteran

    Jan 15, 2011
    Bahamas/ Florida
    I am buying PGA to do my extracts with.I am going to look up everything you said.How do you seal up the whole funnel and jar inside the freezer? When you filter your extracts for the first time using PGA does the PGA evaporate quick?
     
  19. Str8vision

    Str8vision Ultra Member ECF Veteran

    Dec 26, 2013
    Sallisaw, Oklahoma USA
    I don't. The funnel isn't sealed during the actual filtering. Filtering inside the freezer is done using a simple coffee filter, you're just removing the congealed muck that has fallen out of solution. Filtering can take 15 to 60 minutes (depending on the amount of extract you have), ethanol doesn't evaporate very well at extreme low temperatures. Even if it did it wouldn't matter because after freeze filtering is complete the next step is reduction (evaporation). ;) Once I've poured extract into the coffee filter I close the freezer door and simply wait fifteen minutes or so. I then check the progress and add more extract if necessary. I repeat this until all the extract has been filtered. NOTE: When pouring extract into the filter try to exclude the muck that settled in the bottom of the jar, it clogs/slows the filter. If the coffee filter does clog up just replace it with a new one. After all the extract has flowed through, discard the coffee filter, seal the extract inside the jar and move it to a warm place. Leave the jar sealed until the extract reaches room temperature. (If you expose extremely cold extract to warm moist air condensation will rapidly form and just as rapidly be absorbed by the ethanol, it's hygroscopic). Once the extract reaches room temperature you're ready for reduction (evaporation).

    Nope. Evaporation during filtering isn't a concern at all. I perform the final filtering at room temperature after I've reduced the extract by 75%. At this point the ethanol is heavily laden with flavor and is no longer highly volatile, evaporation slows to a crawl. Final filtration performed at room temperature takes only 10 to 30 minutes, there's no loss at all (except to the filter).
     
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  20. Island Vapor

    Island Vapor Super Member Verified Member ECF Veteran

    Jan 15, 2011
    Bahamas/ Florida
    Thanks again for the reply.I just bought 8 pipe tobacco flavors.I will let you know how they came out.
     
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