Yesterday I received my mail order "Distiller's Refractometer" from Homebrew
Heaven and I was playing around with it in measuring the alcohol content of
some of my store-bought liquor.

Then I was thinking "What would my Sugar Brix Refractometer read if I put
drops of alcohol on the viewing prism instead of sugary must?". To my
surprise, my 40% v/v Gordon's London Dry Gin reads about 14 Brix (about 7.5%
potential alcohol). That is totally absurd. I would imagine it would be
somewhere below zero.

Then I figured that the refractometer was doing everything by the refractive
index. Sugar Brix Refractometer is designed to measure sugar content by the
refractive index. It should be correct if used on sugary must before
fermentation. However, if the sugary must undergoes fermentation and much of
the sugar is converted to alcohol, the Sugar Brix Refractometer cannot be
relied upon anymore become the refractive index of alcohol in the
half-finished wine is messing up the reading. I believe you have to go back
to using a conventional floating hydrometer.


Best Regards,

Wannabe
=======

In rec.crafts.brewing WannabeSomeone <WannabeSomeone@removethissympatico.ca> wrote:[color=blue]
> Yesterday I received my mail order "Distiller's Refractometer" from Homebrew
> Heaven and I was playing around with it in measuring the alcohol content of
> some of my store-bought liquor.
>
> Then I was thinking "What would my Sugar Brix Refractometer read if I put
> drops of alcohol on the viewing prism instead of sugary must?". To my
> surprise, my 40% v/v Gordon's London Dry Gin reads about 14 Brix (about 7.5%
> potential alcohol). That is totally absurd. I would imagine it would be
> somewhere below zero.[/color]

For one, you need an original gravity reading and a final brix reading
from the refractometer to get anywhere. There is no way you have the OG
reading for the liquor [distilling really blows that anyway]. Had it
fermented to its final gravity, the brix reading would have to go
through a correction formula to get the final gravity. It is not likely
accurate in any event with 40% alcohol spirits.
[color=blue]
>
> Then I figured that the refractometer was doing everything by the refractive
> index. Sugar Brix Refractometer is designed to measure sugar content by the
> refractive index. It should be correct if used on sugary must before
> fermentation. However, if the sugary must undergoes fermentation and much of
> the sugar is converted to alcohol, the Sugar Brix Refractometer cannot be
> relied upon anymore become the refractive index of alcohol in the
> half-finished wine is messing up the reading. I believe you have to go back
> to using a conventional floating hydrometer.
>[/color]

You need to do some research I think. It is a lot of work to describe
how a refractometer works here. There are online resources you can
easily google up.


--
Thomas T. Veldhouse
Key Fingerprint: 2DB9 813F F510 82C2 E1AE 34D0 D69D 1EDC D5EC AED1