Why do people keep saying it's just water vapor?

[badmotivator]

I genuinely don't understand this. Isn't it glycerine vapor or propylene glycol vapor? (plus whatever small amount of water has been added?) When vaporized, does glycerine decompose into just water? What happens to that carbon in the PG?

If it's not true, can we squash this myth?

 

[rustybikes]

My unscientific explanation of the way I understand it..

PG and VG work the same way, so I'll only reference PG... When the e-liquid is heated in the atty (or carto or whatever), it is heated well past its boiling point and becomes a vapour. It immediately starts to cool, causing water vapour in the ambient environment to condense on the rapidly cooling PG molecules. Note that "ambient environment" includes your lungs, so the water vapour you exhale is mostly from your own lungs. The PG (and nicotine and flavoring) is mostly absorbed by your lungs, so what's left over really is mostly water vapour.

The important distinction I'm trying to get to here is that the the water is already present, it's only the physics of PG that makes it visible.

 

[badmotivator]

Interesting idea, thanks. But when explaining where the visible vapor comes from, why do we need to bring water in? Why do we think the vapor isn't entirely recondensed PG or VG?

I'd love to see a good source outside ECF which deals with this if anyone knows one.

Thanks for input and ideas.

 

[ChinMullet]

I've always wondered as well. What's coming out of my PV is not water vapor. It looks suspiciously similar like blue cigarette smoke, not clear mist water vapor. Then again, wtf do I know?

 

[six]

Since you got an answer regarding PG, I'll give you a little on VG (they do happen to be chemically similar)

Vegetable Glycerin is 3 carbon atoms, 3 hydrogen atoms, and 3 OH groups. OH groups are otherwise referred to as Hydroxyl and are one Oxygen atom bonded to one Hydrogen atom (without having to type ten paragraphs --it's pretty much the sub-structure of water). It's worth taking an organic chemistry class to have any sort of understanding of the covalent bond. When you heat glycerin to its boiling point (change it from its liquid state to vapor state), you make some changes to the covalent bond and begin attracting more Hydrogen atoms if they exist (just assuming this is vaping and not some sort of experiment in a vacuum).

So, vaporizing glycerins outside a vacuum ends up creating quite a lot of H2O when the bond attracts more hydrogen from our general atmosphere or steals more hydrogen from the existing 3 hydrogen molecules that are already in glycerin.

You did question what happens to the carbon atoms, but I can't answer that without more organic chemistry education than I have... or maybe a better memory than I have. The last organic chemistry class I took was in maybe 1989 and I never worked in any field that required me to remember much of it.

 

[scribes]

http://chemistry.about.com/od/howthingswork/a/smokemachines_3.htm

 

[Randyrtx]

I forgot I still had this link... the best explanation I've found: Chemistry Connections: The Chemical Basis of Everyday Phenomena - Kerry K. Karukstis, Gerald R. Van Hecke - Google Books

 

[badmotivator]

Thanks, scribes. That was interesting, but it doesn't really address our vapor; fog machines use mostly water anyway, or cold nitrogen.

I'm still in the dark, but I'm still inclined to think that PVs produce glycol fog, not water fog. Which is totally fine with me. I don't have a stake either way, I'm just not getting why people say it's "just water vapor". Wishful thinking? It can't be "just" water vapor, and I still doubt it contains any significant amount of water beyond breath or ambient humidity.

School me, chemists! One way or the other, doesn't matter.

 

[six]

Thanks, scribes. That was interesting, but it doesn't really address our vapor; fog machines use mostly water anyway, or cold nitrogen.

I'm still in the dark, but I'm still inclined to think that PVs produce glycol fog, not water fog. Which is totally fine with me. I don't have a stake either way, I'm just not getting why people say it's "just water vapor". Wishful thinking? It can't be "just" water vapor, and I still doubt it contains any significant amount of water beyond breath or ambient humidity.

School me, chemists! One way or the other, doesn't matter.

It creates a lot of water. I don't think everything we exhale is "just water vapor" -- in fact, that's certainly false. But, boiling glycerins and glycols does indeed create water vapor.

 

[badmotivator]

Another cool link, Randyrtx, but same problem. The fog machines the books discuss may not be analogous to the vapor my PV makes. Darn.

 

[badmotivator]

It creates a lot of water. I don't think everything we exhale is "just water vapor" -- in fact, that's certainly false. But, boiling glycerins and glycols does indeed create water vapor.

Perhaps, but I can't take that as an article of faith. Can you explain how boiling juice creates water vapor? I'm ignorant of any mechanism which might do this.

 

[Jimbo52]

PG and VG are Humectants, absorbing water from the surrounding air, and produce water vapor in our PV's.

 

[thatguyjeff]

It (the vapor that we exhale) is very much the same thing as naturally occurring fog, plus a little nicotine, PG/VG vapor, and vaporized flavor elements. What is seen is very literally fog - or suspended condensed water vapor.

Certain specific conditions must be present in order for fog to occur naturally - relative humidity, dewpoint, temperature, etc. When the mix in the air is just right, the water vapor that's present in the air condenses to form visible fog.

The difference with a PV is that the conditions needed to create fog aren't occurring naturally. The heat applied to the juice is creating a little tiny microclimate in that cartomizer to condense the water vapor in the air enough to be visible.

It is indeed water vapor - probably 99.99% water vapor.

 

[badmotivator]

PG and VG are Humectants, absorbing water from the surrounding air, and produce water vapor in our PV's.

I can appreciate that the hygroscopic quality of juices can amplify the volume of the fog, but by how much? How many tiny water molecules of water can a big ol' PG molecule hold on to? One? Two? A hundred?

Any desert dwellers care to compare vapor production on low-relative-humidity days to high ones?

 

[Genericname]

so we need a test... vape in extremely high and low humidity, take a video, the higher the humidity in the air the more vapor there should be. I do think it's irresponsible to call it "just water vapor", whatever else is in there is on its way out of your PV, and your lungs into the air around you.

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[Genericname]

another thought, if it were 99.99% water people wouldn't have any problems vaping PG, unless that mix of 0.01% of pg and all the other goodies is enough to cause adverse reactions.

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[badmotivator]

Does anyone here have access to a dry room or a dry box? Also, you would need a mechanical means of drawing the vapor, since part of the water vapor hypothesis is that it's largely breath humidity making the fog.

 

[thatguyjeff]

another thought, if it were 99.99% water people wouldn't have any problems vaping PG, unless that mix of 0.01% of pg and all the other goodies is enough to cause adverse reactions.

Sent from my DROID RAZR using Tapatalk 2

The visible fog part of the vapor is 99% water I believe, the visible part. There's all sorts of unseen stuff there too.

 

[Randyrtx]

Another cool link, Randyrtx, but same problem. The fog machines the books discuss may not be analogous to the vapor my PV makes. Darn.

The glycol-based fog machines operate on the same principle as e-cigs. Heated glycols form hydroscopic bonds with water molecules (either in the liquid or in the air) to form a visible gas vapor. It's visible because of the light scattering properties of the bound gaseous molecules.

In a way, calling it "water vapor" is partially accurate, but it also happens to contain other things besides just water. I tend to say that it's "similar to theatrical fog" if the subject comes up, personally.

 

[six]

Perhaps, but I can't take that as an article of faith. Can you explain how boiling juice creates water vapor? I'm ignorant of any mechanism which might do this.

I already did above. Glycerins and glycols have 3 carbon, 3 hydrogen, and 3 OH groups. When you turn that in to vapor, the OH bond changes and attracts hydrogen. So, you go from having OH (one oxygen and one hydrogen) groups to the OH groups attracting hydrogen atoms to make H2O molecules. The covalent bond is already prone to attracting another hydrogen, but boiling makes it happen. -- I have no idea what happens to the 3 carbon atoms. I'd need an organic chemistry refresher to answer that.