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
Re: Flame test of alcohols
Posted: Mon Aug 19, 2019 12:25 am
by Saltbush Bill
Nice work Yummy
What has been used to fuel those lamps before hand?
The wicks could have residue from previous fuels.
Re: Flame test of alcohols
Posted: Mon Aug 19, 2019 12:44 am
by Birrofilo
Also, when burning a substance with a wick, also the wick is burning I suppose, even though slowly.
Re: Flame test of alcohols
Posted: Mon Aug 19, 2019 1:16 am
by Yummyrum
Saltbush Bill wrote: ↑Mon Aug 19, 2019 12:25 am
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 .
Birrofilo wrote: ↑Mon Aug 19, 2019 12:44 am
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 .
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........
Re: Flame test of alcohols
Posted: Tue Feb 11, 2020 8:06 pm
by 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.
Re: Flame test of alcohols
Posted: Tue Feb 11, 2020 8:30 pm
by 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.
Re: Flame test of alcohols
Posted: Tue Feb 11, 2020 11:51 pm
by shadylane
Alchemist75 wrote: ↑Tue Feb 11, 2020 8:06 pm
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
Re: Flame test of alcohols
Posted: Wed Feb 12, 2020 2:20 am
by Saltbush Bill
shadylane wrote: ↑Tue Feb 11, 2020 11:51 pm
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.
Re: Flame test of alcohols
Posted: Wed Feb 12, 2020 9:28 am
by 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.
Re: Flame test of alcohols
Posted: Wed Feb 12, 2020 1:52 pm
by 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
Re: Flame test of alcohols
Posted: Thu Feb 13, 2020 4:20 pm
by Chauncey
10c is 50f so a little higher
Re: Flame test of alcohols
Posted: Tue Nov 15, 2022 3:52 pm
by Bradster68
This is some over the top stuff right here.
Very cool project/experiment.
Re: Flame test of alcohols
Posted: Tue Nov 15, 2022 8:51 pm
by dunluce
Cool experiment, definitely proves for me you can't tell by looks and colour.
Saltbush Bill wrote: ↑Wed Feb 12, 2020 2:20 am 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
Re: Flame test of alcohols
Posted: Thu Oct 05, 2023 12:32 am
by Saltbush Bill
Hope you dont mind Yummy, thought this one belonged here with yours........same shit different day.
Re: Flame test of alcohols
Posted: Thu Oct 05, 2023 2:32 pm
by Yummyrum
Good place for it Salty . And more evidence that the flame test is useless.