can tell change in strength by UV light

absinthe · Post by **absinthe** » Sun Jul 02, 2006 8:05 am

i have made a strange discovery i set up my web-cam so i can see the flow and temp o my still.
but i have modified my web-cam by removing the UV filter and putting UV LEDs in it so it was more sensitive in the dark, and i have found that the impurity's show up brown under UV light the more pure the clearer the distillate,
no exact way of telling purity but it was interesting to see the change.

hornedrhodent · Post by **hornedrhodent** » Sun Jul 02, 2006 9:51 am

Keep us posted - Do you have an alcometer? Can you correlate appearance on you webcam with Alcohol % or subjective taste or both.

Are we talking reflux or pot still?

absinthe · Post by **absinthe** » Mon Jul 03, 2006 8:55 am

it was a stripping run of about 28 ltr of aprox 22% as it had a good amount of tails etc from other batches.
it ranged from 80% down to 40% in 2 ltr bottles, tested with an alcometer. nah not exact enough for any testing but with the bottles in a line you can see a slight difference in colour.
it was in a 40 inch refux still with no packing or reflux to just do the strip.

Kiint · Post by **Kiint** » Tue Jul 04, 2006 1:19 pm

UV or IR?

Most cameras have an IR filter because the IR can affect the image if there is no filter. UV is too short a wavelength to see anything.

IR LED's are also used to illuminate in the dark since IR is not a visible wave length it can be used to illuminate areas for IR sensitive cameras without people knowing there is any lights.

But, as far as your assumptions go, with a macro lens and stuff it could actually work.

For instance, test the camera with a glass of Coke, the coke should appear clear (yes thats correct) while things like hair and other "coloured" objects can change depending on things.

The idea of using IR to test purity is quite unique, I have never heard of it, but the theory that certain particles absorb/reflect IR (hence have a darker/lighter appearance) is well known, its just a matter of determining which particles are affected by IR to determine what it is thats going on.

absinthe · Post by **absinthe** » Tue Jul 04, 2006 10:29 pm

yeah sorry i meant IR was a wee bit tired and tipsy when i wrote that....

canadianmoonshiner · Post by **canadianmoonshiner** » Sat Jul 08, 2006 6:53 am

Think this topic is dead.

The IR light was simply showing the temperature difference. The first bottle in your line would be cooler (less red), & the last one would be quite warm (more red).

absinthe · Post by **absinthe** » Sat Jul 08, 2006 7:01 am

no it not heat sensitive IR not enough depth for that and they were all coming out at about 15 deg C they would have had tops 1 deg difference but about 5-10% alcohol difference

possum · Post by **possum** » Sat Jul 08, 2006 10:24 am

I am unsure about IR absorbtion/transmition wavelengths for ethanol, but organics in general tend to absorb IR light. More organics disolved would generally mean more IR absorbed.

agl · Post by **agl** » Tue Jul 11, 2006 3:15 pm

now this looks like an interesting project!
I have a Uv-vis spectrophotometer at work which can read into the near IR. Webcams, as far as I know (without filter) can read to a wavelength of 950nm (visible spectrum spans from 400-800nm), I will check when I get to work what the response of my spectrophotometer is, but I think it is at least out to 900 nm, if this is the case, I will be able to find absorbtion bands in some samples of tails, that shouldn't be present in the middle runs for example. if the device can't I might look into making a simple near-IR spectrophotometer with a webcam and a diffraction grating.

hornedrhodent · Post by **hornedrhodent** » Sat Jul 15, 2006 4:26 am

agl wrote: I might look into making a simple near-IR spectrophotometer with a webcam and a diffraction grating.

Ah - the wonders of modern technology - What used to be 'state of the art' when I used to be a metallurgist, is now a home brew electronics and computer hobby activity.