Flame test of alcohols

[Yummyrum]

I was setting up some spirit lamps at work today and I thought I'd take some pics as recently there was a mention of checking for methanol by the colour of burning it .

I had to set up 4 x lamps with Methanol , Ethanol , Butan-1ol or 1-Butanol and propan-1ol or 1-Propanol .

Here's a close up of each .

Then I thought , OK does it look the same if you burn them on a spoon .So I set a few drops in a well plate .
The results are completely different to the spirit lamp test .The Very yellow looking Methanol flame on the burner is a very blue flame with no sign of yellow at all . If you look at the tip of the Ethanol flame you can see a slight yellow tinge .

And remember that these are pure alcohols . I don't recon anyone could guess what was in their spoon off the still

[Saltbush Bill]

Nice work Yummy
What has been used to fuel those lamps before hand?
The wicks could have residue from previous fuels.

[Birrofilo]

Also, when burning a substance with a wick, also the wick is burning I suppose, even though slowly.

[Yummyrum]

Nice work Yummy
What has been used to fuel those lamps before hand?
The wicks could have residue from previous fuels.

They are the same year after year Salty ...for that reason ....no cross contamination .

Also, when burning a substance with a wick, also the wick is burning I suppose, even though slowly.

I think this has a lot to do with it . But it sure is interesting how the Methanol can go from a yellow with a wick to a blue on its own .

[seamusm53]

This is an interesting video and discussion.

https://www.reddit.com/r/chemicalreacti ... nol_right/

My take from all this - don't trust your life to be able to tell the difference based on a flame test when adulteration is usually a deliberately poisoned mix of ethanol and methanol not pure methanol. I know what comes from my own handiwork and at least here at home feel reasonably safe drinking commercial spirits. But otherwise........

[Alchemist75]

The only thing i've ever been able to deduce using the "flame test" on product taken off the still was a rough gauge of proof. A tall blue flame with a pronounced gold cap that leaves the spoon dry is gonna be 85%+, the more tall and pronounced, the higher proof. A lower blue flame with little to no gold cap leaving water behind is below 75-80%. Approximate test at best and no indication of contamination unless it's really burning an off color.

[cayars]

The color or lack of color will depend on what you run as well.

There really isn't much useful information to get from a flame test. It can be pretty easy to not even see a flame at times. Setting alcohol on fire probably isn't the smartest move we can do even if done over a sink.

I've got a big utility sink in my basement. Goofing around I dumped foreshots in the sink. Did a flame test on a spoon and dumped that into the sink. You know what happened next, the foreshots that didn't go down the drain caught fire just like I thought they would. Flame tests are an accident waiting to happen.

[shadylane]

The only thing i've ever been able to deduce using the "flame test" on product taken off the still was a rough gauge of proof. A tall blue flame with a pronounced gold cap that leaves the spoon dry is gonna be 85%+, the more tall and pronounced, the higher proof. A lower blue flame with little to no gold cap leaving water behind is below 75-80%. Approximate test at best and no indication of contamination unless it's really burning an off color.

Don't forget the air temp
It can be difficult to get even high proof to light on a cold day.
On a hot day, you'll know it's lit when the hairs on your hand start curling up

[Saltbush Bill]

Don't forget the air temp
It can be difficult to get even high proof to light on a cold day.

Hell how cold does it get there......that problem doesnt exist in my neck of the woods.

[Alchemist75]

Yep, if it's hot enough even 25% will ignite. Shoot, on a frigid cold day like yesterday even my lighter has trouble striking.

[shadylane]

100% alcohol has a flash point of around 13'c
For the forum members from the scientifically challenged part of the world
That equals 50 something degrees Fahrenheit

[Chauncey]

10c is 50f so a little higher

[Bradster68]

This is some over the top stuff right here.
Very cool project/experiment.

[dunluce]

Cool experiment, definitely proves for me you can't tell by looks and colour.

Hell how cold does it get there......that problem doesnt exist in my neck of the woods.

I can confirm that up here in Canada it gets cold enough that the butane in a lighter will not evaporate and rise up to the spark on the flint.

Two weeks last Christmas were -45 C..... No shortage of ice for liebig water. Lol

[Saltbush Bill]

Hope you dont mind Yummy, thought this one belonged here with yours........same shit different day.

[Yummyrum]

Good place for it Salty . And more evidence that the flame test is useless.