It isn't cool that I just posted this to the wrong subreddit, lol. I'll leave it up but it wasn't intended for DIY_eJuice oops.

Need coffeeeeee.

They just have penis envy.

That's the question -- considering that the research paper only goes from 0.0002% to 0.001% there's a HUGE range of what might be too little and what might be too much!

I'm going to play more this week with 10% citric acid diluted to 0.1% (as I always do) and then dilute that again to 0.1% in the final solution (0.0001%!) and tweak up from there and see if it makes a difference or not.

It does appear that we're just abusing CA, but will it matter in eliquid?

The more important percentage appears to be CA:flavor volatile, and since we don't really know the volatile percentage, it's hard to match up the CA.

I think trial and error may help a LOT, but that means patient note taking.

That's a good question -- and yes, it's possible. Using an acid (like citric, malic, tartaric, etc) may enhance one note while muting another, depending on the ratio of acid to that compound.

What those values are, specifically, is impossible to know at this point because it's also impossible to know what we're mixing with specifically (except for certain TFA flavors which have an estimated recipe list of compounds).

> Whereas the vaped liquid will have fewer aroma compounds present due to their liberation during the storage period.

That's the question -- is removing it from solution GOOD or BAD? Does keeping it in solution actually mean that we're able to taste/smell it more during aerosolizing, or does releasing it from the solution also mean we release more when we vape it?

I talked to 3 chemists last week and all of them just shrugged and said "good question, no one knows" lol.

> but it will limit the overall shelf life of the juice?

That's also a question I asked -- I don't have ANY long term tests with and without citric acid in solution. I have to get on that and mix up some blends to sit around for 3 months and see if it actually helps or hinders.

Since most DIYers prefer shake-and-vape it might not be a big question, but if they want to transition to larger scale mixing, it's possible it would have a drastic negative effect if they pre-mix and pre-steep larger batches.

That's the idea -- the usage of an acid (citric, in this case) to blunt certain flavor notes while highlighting others.

Citric Acid should have zero effect on color -- it's more likely than some of the compounds are just oxidizing over time. I have vanillin compounds that stay clear for 2 months and then all of a sudden start turning brownish/amber. That's without any nicotine or other flavors in them.

That's my guess, too! Maybe it's muting some esters (locking them down) over time, but early on it might just be releasing them from solution initially.

yeah i shitposted in the wrong subreddit, lol

Thanks!

Well shit I just realized I posted this to the wrong subreddit. FML.

It appears, at least in my casual digging, that citric acid is truly best suited to releasing ester compounds -- I have a limited short list available at this link. But it affects each ester in different ways at different amounts.

Since the flavor concentrates we use aren't disclosed fully as to what they contain, you really have to do a lot of your own research to see what works, and what doesn't.

Over time I'm hoping I can unlock the recipe lists of every flavor concentrate (costs me $120-$250 per flavor concentrate to get an estimated recipe!) so we can use science better in creating better flavors.

I love citric acid but it's a love-hate relationship because I was never able to understand WHY the acid was working WHEN it worked -- and why sometimes it would totally destroy and mute flavor.

Now I have a better idea, and it boils down to DIY truth #1: you're overusing something.

I do remember Fizz actually retracting the addition of citric acid, as he said that CA mutes the mix after a week or so.

What I'm guessing is that the amount/concentration of citric acid added to the nana cream clone is way too much (according to /u/abdada's post), but for the first week, the CA hasn't quite homogenized with the other flavors/liquid. After most of the volatiles have come together, that's when the muting occurs.

So, I think citric acid does actually play a role in Fizz's recipe, just adding the tiniest fraction of it would be better.

To be honest, I haven't played with my 10% CA solution since reading Fizz's comments on citric acid muting his mix, as I was afraid of those results. I might now ultra-dilute it to 1% and start messing about with it.

It's possible that's working because it's muting some noxious compounds -- while also letting out only a little bit of something that tastes good in reduced amounts.

Don't adjust downwards necessarily -- it's something to just be aware of if you're adding citric acid.

Playing with the ratio can help a lot, though.

Yes, lowering pH definitely increases my nicotine buzz although only at higher-than-normal nicotine levels than I usually vape.

Esters are one of many fruit notes -- terpenes are different compounds that appear as citrus (mostly because that's where they are most frequently derived from).

As to why TFA Juicy Peach tastes bad when vaped, it's tough to say. The non-DX version is mostly lactones (creamy, fatty, fruity) and esters (fruity) with some acetoin (diketone-like) thrown in for overall creaminess.

It also contains linalool, a terpene, which is really obnoxious to me. I HATE linalool and avoid it if I can. Linalool for some palates needs to be used at an extra-low percentage or it becomes harsh and nail polish-like.

One thing to be aware of is that linalool breaks down slowly when interacting with oxygen/air. The breakdown can (and does) cause some negative reactions in certain people, including eczema and other contact dermatitis -- maybe you're just sensitive to that.

I would be surprised if that's the case. IIRC, enamel hypocalcification likely comes from metabolic stress during one's younger formative years -- look at Goodman and Song's 1999's paper on it, as well as Goodman's 1994 precursor to it and their hypothesis that diet isn't going to have an effect on the state of enamel calcification in adulthood.

Also Dahlberg 1991 and Duray 1996 posited that it isn't nutritive but environmental and developmental stresses.

I strongly strongly strongly recommend you hunt down some fermeted cod liver oil/butter oil and work on remineralization with a 60-90 day self-treatment of FCLO/BO (vitamin K2, specifically) to see if there's an immediate change!

Each acid affects different volatile compounds for sure.

there's a reference paper that talks about malic acid and hexenal (etc) in kiwifruit to bring out banana flavors, and using citric acid to bring out lemon flavors (from kiwifruit).

obviously there's a ton of research to do (or a ton of research that exists in proprietary/trade secret form).

I have acetic acid (95%) and lactic acid (90%) that are interesting in certain mixes.

I was recently reading a great paper on matching color with flavor. When participants were given cherry flavoring colored green, 29% of them tasted lime! So color is off limits for vaping, but it shows that perception is everything.

Another recent paper (2015) spoke about mouthfeel from acids in alcoholic cider -- that's also a solid read about using acidulants to actually mimic mouth feel even though there's no physiological reason why an acid flavor would be interpreted as mouthfeel.

A few acids I have on order are fumaric and succinic -- both which appear to be useful although at incredibly low dilution percentages.

From what I've gathered with very recently testing, I do believe that some of the mixers with more ground under their feet are creating difficult to mimic flavor profiles thanks to very, very dilute acids which may be releasing certain compounds from well known concentrates while muting other compounds in the same solutions.

It's like copy protection for a recipe -- using an acid to amplify and mute certain "frequencies" of the signal.

The recent papers I've read (even 2015) show there's a lot that flavor scientists still don't know about this field -- which is exciting to look deeper into things that science may not have the budget to look into.

Also noted that caramel and butterscotch flavor notes can mask the perception of certain sour note flavors (citrus, apples, pears, etc) while amplifying the 'meaty fruit' notes in those same flavors. So adding an acid to these combos may just mute everything.

Also, it's an honor to have you in this thread.

Possibly. The percentage appears more important as a percentage against total volume/weight of the aroma volatiles and not just the total solution, so the 0.0002% of total solution is just an average and may vary based on the actual total percentage of the volatiles in the solution.