Article Stating That 70% Isopropyl Alcohol is a Better Disinfectant than 99%

[Bowie]

Those of restoring estate pipes may find this information interesting. I'm not posting this to as an argument that 70% is the "correct" way or that using 91%+ is "wrong." I'm not a scientist or in a relevant field and cannot competently comment on the findings in the article, so I simply present it as something of interest. There is also some information about rubbing and denatured alcohol.

Why Is 70% Isopropyl Alcohol (IPA) a Better Disinfectant than 99% Isopropanol, and What Is IPA Used For? - https://blog.gotopac.com/2017/05/15/why-is-70-isopropyl-alcohol-ipa-a-better-disinfectant-than-99-isopropanol-and-what-is-ipa-used-for/

Interesting extracts:

The presence of water is a crucial factor in destroying or inhibiting the growth of pathogenic microorganisms with isopropyl alcohol. Water acts as a catalyst and plays a key role in denaturing the proteins of vegetative cell membranes. 70% IPA solutions penetrate the cell wall more completely which permeates the entire cell, coagulates all proteins, and therefore the microorganism dies.

Solutions > 91% IPA may kill some bacteria, but require longer contact times for disinfection, and enable spores to lie in a dormant state without being killed. A 50% isopropyl alcohol solution kills Staphylococcus Aureus in less than 10 seconds (pg. 238), yet a 90% solution with a contact time of over two hours is ineffective.

 

[jpmcwjr]

Veeeeery Interesting!

I much prefer a good hot water flush, and letting dry very well. Then the mouth piece is as clean as the flatware in any decent restaurant, probably better over all.
For the ultra careful on a new acquisition, do first the alcohol soak, then flush with hot water, then dry thoroughly.

Note: None of the above is a full sterilization of the pipe. But it has worked for centuries.

 

[greeneyes]

I think usually we're not trying to 'disinfect' a pipe, in the sense of killing microorganisms, but rather physically/chemically remove residues, tars, and other types of "gunk" from the pipe.

In that sense a stronger solvent is more efficient. If the goal is to kill cooties on the stem then 70% alcohol will work just fine.

 

[mingc]

I think usually we're not trying to 'disinfect' a pipe, in the sense of killing microorganisms, but rather physically/chemically remove residues, tars, and other types of "gunk" from the pipe.

In that sense a stronger solvent is more efficient. If the goal is to kill cooties on the stem then 70% alcohol will work just fine.

That makes sense to me. OP's info on disinfection is very helpful for non-pipe purposes tho.

 

[Bowie]

I think usually we're not trying to 'disinfect' a pipe, in the sense of killing microorganisms, but rather physically/chemically remove residues, tars, and other types of "gunk" from the pipe.

In that sense a stronger solvent is more efficient. If the goal is to kill cooties on the stem then 70% alcohol will work just fine.

I agree. I've only cleaned up a couple of pipes (I'm new to this), and it was the gunk that was the hard part. Disinfecting them was a secondary concern, and I imagine the germs just jump right back on in-between smokes while the pipes sit in my basement workshop.

 

[logs]

The germ aspect of pipe tobacco is the kind of thing I try not to think about too much because it makes me anxious.
Watch any production video on making pipe tobacco. Hygienic processing and food safety aint part of the equation. My wife used to fear that restaurant staff might spit in her food if she returned something or complained about her order... like that's the worst thing that could happen to someone. But I'd suspect pipe tobacco is way dirtier than human spit. We're just shoveling bacteria into our pipes every time we smoke. At least we're setting it on fire and presumably killing most of it. Still, it alarms me when I hear people talking about chewing on rope tobacco. You might as well be licking the factory floor.

 

[Burley Guy]

Those of restoring estate pipes may find this information interesting. I'm not posting this to as an argument that 70% is the "correct" way or that using 91%+ is "wrong." I'm not a scientist or in a relevant field and cannot competently comment on the findings in the article, so I simply present it as something of interest. There is also some information about rubbing and denatured alcohol.

Why Is 70% Isopropyl Alcohol (IPA) a Better Disinfectant than 99% Isopropanol, and What Is IPA Used For? - https://blog.gotopac.com/2017/05/15/why-is-70-isopropyl-alcohol-ipa-a-better-disinfectant-than-99-isopropanol-and-what-is-ipa-used-for/

Interesting extracts:

The presence of water is a crucial factor in destroying or inhibiting the growth of pathogenic microorganisms with isopropyl alcohol. Water acts as a catalyst and plays a key role in denaturing the proteins of vegetative cell membranes. 70% IPA solutions penetrate the cell wall more completely which permeates the entire cell, coagulates all proteins, and therefore the microorganism dies.

Solutions > 91% IPA may kill some bacteria, but require longer contact times for disinfection, and enable spores to lie in a dormant state without being killed. A 50% isopropyl alcohol solution kills Staphylococcus Aureus in less than 10 seconds (pg. 238), yet a 90% solution with a contact time of over two hours is ineffective.

Very interesting! Thanks for sharing.

 

[Chasing Embers]

Still, it alarms me when I hear people talking about chewing on rope tobacco. You might as well be licking the factory floor.

I used to work in the food industry. Want to know what the FDA considers acceptable in food production??

 

[warren]

"At least we're setting it on fire"

True and if you don't do that you can't get the carcinogens. So, pick yer poison.

 

[olkofri]

Well, I am actually disinfecting, and not removing gunk when I apply alcohol to a pipe. But, I wouldn't use any alcohol I wouldn't drink, so isopropanol is out: vodka is in.

The findings are interesting to me in other areas: namely, after shave disinfection: guess I should now use 70% instead of the 99% I normally buy/use.

 

[peregrinus]

Well, I am actually disinfecting, and not removing gunk when I apply alcohol to a pipe.

Despite all assurances to the safety of other forms of alcohol, I also prefer to use vodka. I like to think I’m doing both removing gunk and sterilizing. However, as pointed out, a lit bowl of tobacco is not an environmentally friendly place for most bacteria. With estate pipes I am not as concerned about the briar as I am the stems, and they (normally) get a dip in a diluted bleach solution and a subsequent polish.

 

[Chasing Embers]

Well, I am actually disinfecting,

What do you do about the germs on the outside of the pipe or the tobacco. Can you imagine all of the unsanitary hands that have been on both, or where those hands have been?

 

[ssjones]

For the purpose of a soak with sea salt, I can't imagine the alcohol % would make any difference in the result. I'll keep using 99% iso-propyl, because it is readily available.

 

[olkofri]

What do you do about the germs on the outside of the pipe or the tobacco. Can you imagine all of the unsanitary hands that have been on both, or where those hands have been?

As much as I can. As a matter of fact, I have what I call a Pilate Complex: I wash my hands dozens of times a day.

 

[Chasing Embers]

As much as I can. As a matter of fact, I have what I call a Pilate Complex: I wash my hands dozens of times a day.

Gotcha. Babyganics has a line of mild disinfecting wipes that I use on surfaces, including pipes, that I don't want to damage the finish. Alcohol free and kills the requisite 99.9% of germs.?

 

[ophiuchus]

As much as I can. As a matter of fact, I have what I call a Pilate Complex: I wash my hands dozens of times a day.

I work the lab of a preventative health clinic. I totally relate. I wash my hands 20+ times a day, and enjoy having an excuse that exonerates me from the compulsive handwashing diagnosis.

 

[Chasing Embers]

I wash my hands 20+ times a day

I spent 15 years in the food industry and can't break the habit.

 

[ophiuchus]

I spent 15 years in the food industry and can't break the habit.

Well, I’d eat where you cooked. Well, If you were working ... ?

 

[frozenchurchwarden]

At least we're setting it on fire and presumably killing most of it.

Not in the shank and stem. I’d argue that most of the spoilage that people want to avoid is actually from bacteria in the shank. Not to mention it’s common to finish your a bowl with a soggy bundle of dottle.
In that regard it might be wise to have two alcohol solutions ready and apply both 99% and 70% separately.

 

[jpmcwjr]

Not in the shank and stem. I’d argue that most of the spoilage that people want to avoid is actually from bacteria in the shank. Not to mention it’s common to finish your a bowl with a soggy bundle of dottle.
In that regard it might be wise to have two alcohol solutions ready and apply both 99% and 70% separately.

A hot water flush achieves the same level of bacteria removal, as well as being cheaper and more convenient than alcohol, which use may impact the briar itself.

And soggy dottle? Any dottle should be removed fairly soon, but if you dry your tobacco, you won't have a soggy bottom. I gore-an-tee it.