"WannabeSomeone" > wrote in message
.. .
> 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.

That's exactly right. Once the fermentation has begun, your refractometer
is useless.

Tom S

Tom,

I do not use a refractometer but here a while back I saw a table ore
equation published that related refractometer measurements to alcohol/sugar
mixtures. A hydrometer should not be useable with a water/sugar/alcohol mix
but because people have worked out the relationship you can. I seen no
reason why the same could be done with a refractometer.

Anyway there is such a table out there. You might try to dig it up and see
if you believe it.

Ray

"Tom S" > wrote in message
m...
>
> "WannabeSomeone" > wrote in message
> .. .
>> 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.
>
> That's exactly right. Once the fermentation has begun, your refractometer
> is useless.
>
> Tom S
>

Ray Calvert wrote:
> Tom,
>
> I do not use a refractometer but here a while back I saw a table ore
> equation published that related refractometer measurements to alcohol/sugar
> mixtures. A hydrometer should not be useable with a water/sugar/alcohol mix
> but because people have worked out the relationship you can. I seen no
> reason why the same could be done with a refractometer.
>
> Anyway there is such a table out there. You might try to dig it up and see
> if you believe it.
>
> Ray
>

Here is the link again:

http://valleyvintner.com/Refrac_Hydro/Refract_Hydro.htm

Pp

"pp" > wrote in message
oups.com...
>
> Ray Calvert wrote:
>> Tom,
>>
>> I do not use a refractometer but here a while back I saw a table ore
>> equation published that related refractometer measurements to
>> alcohol/sugar
>> mixtures. A hydrometer should not be useable with a water/sugar/alcohol
>> mix
>> but because people have worked out the relationship you can. I seen no
>> reason why the same could be done with a refractometer.
>>
>> Anyway there is such a table out there. You might try to dig it up and
>> see
>> if you believe it.
>>
>> Ray
>>
>
> Here is the link again:
>
> http://valleyvintner.com/Refrac_Hydro/Refract_Hydro.htm
>
> Pp
>


This is an excellent link you have provided. The equation involves a third
degree polynomial. Lucky it also provides a spreadsheet to do the
calculation. Once again, thank you.


Best Regards,
Wannabe
=======

"Ray Calvert" > wrote in message
m...
> Tom,
>
> I do not use a refractometer but here a while back I saw a table ore
> equation published that related refractometer measurements to
> alcohol/sugar mixtures. A hydrometer should not be useable with a
> water/sugar/alcohol mix but because people have worked out the
> relationship you can. I seen no reason why the same could be done with a
> refractometer.
>
> Anyway there is such a table out there. You might try to dig it up and
> see if you believe it.

Why bother? Once the fruit is in the tank there's no reason not to use a
hydrometer. Refractometers are nice for field testing but not necessary
once you get past the crusher and into fermentation.

Tom S

I agree Tom. That is why I do not use a refractometer. Hydrometers are
much cheaper. A refractometer is great in the field for checking grapes but
even then you need to check the batch and a hydrometer is the way to go
IMHO. But it comes up every now and then that a refractometer CAN NOT be
used after initial crush and in fairness that does not seem to be true.

Ray

"Tom S" > wrote in message
...
>
> "Ray Calvert" > wrote in message
> m...
>> Tom,
>>
>> I do not use a refractometer but here a while back I saw a table ore
>> equation published that related refractometer measurements to
>> alcohol/sugar mixtures. A hydrometer should not be useable with a
>> water/sugar/alcohol mix but because people have worked out the
>> relationship you can. I seen no reason why the same could be done with a
>> refractometer.
>>
>> Anyway there is such a table out there. You might try to dig it up and
>> see if you believe it.
>
> Why bother? Once the fruit is in the tank there's no reason not to use a
> hydrometer. Refractometers are nice for field testing but not necessary
> once you get past the crusher and into fermentation.
>
> Tom S
>

Ray Calvert wrote:

> I agree Tom. That is why I do not use a refractometer. Hydrometers are
> much cheaper. A refractometer is great in the field for checking grapes
> but even then you need to check the batch and a hydrometer is the way to
> go
> IMHO.

If that is the case, why then, do you suppose that brix measurement is the
standard measurement used pre-harvest and at harvest in the wine industry
and NOT SG?

> But it comes up every now and then that a refractometer CAN NOT be
> used after initial crush and in fairness that does not seem to be true.
>
> Ray
>
> "Tom S" > wrote in message
> ...
>>
>> "Ray Calvert" > wrote in message
>> m...
>>> Tom,
>>>
>>> I do not use a refractometer but here a while back I saw a table ore
>>> equation published that related refractometer measurements to
>>> alcohol/sugar mixtures. A hydrometer should not be useable with a
>>> water/sugar/alcohol mix but because people have worked out the
>>> relationship you can. I seen no reason why the same could be done with
>>> a refractometer.
>>>
>>> Anyway there is such a table out there. You might try to dig it up and
>>> see if you believe it.
>>
>> Why bother? Once the fruit is in the tank there's no reason not to use a
>> hydrometer. Refractometers are nice for field testing but not necessary
>> once you get past the crusher and into fermentation.
>>
>> Tom S
>>

Actually neither is perfect but both are good enough at harvest as far
as I am concerned. Both calibrations rely on pure sucrose; niether
scale nor device has a fudge factor added to compensate for the other
things found in must. That said, it's not important to compensate for
them. The values considered optimal at harvest were arrived at
empirically a long time ago and the most important (to taste) other
solid involved is the acids. Ther are good ways to determine the acid
balance at maturity too.

Measurement technique affects both devices; I would not say one has an
advantage over the other. Both have well known limitations that should
be considered. I don't use a refractometer personally but would if I
grew the grapes myself. I would still use the hydrometer too, but
that's my way.

Joe

"Paul E. Lehmann" > wrote in message
...
> Ray Calvert wrote:
>
>> I agree Tom. That is why I do not use a refractometer. Hydrometers are
>> much cheaper. A refractometer is great in the field for checking grapes
>> but even then you need to check the batch and a hydrometer is the way to
>> go
>> IMHO.
>
> If that is the case, why then, do you suppose that brix measurement is the
> standard measurement used pre-harvest and at harvest in the wine industry
> and NOT SG?

Specific gravity readings include _all_ dissolved solids, including whatever
acids are present, and are therefore inherently inaccurate for measuring
sugar. E.g., a juice at 23° Brix and 1.0 gram TA/100 ml will read 1.098
S.G. (24° Brix). Refractometers measure _only_ the sugar, so render a more
accurate measurement.

They're also a lot more convenient and rugged for field use.

Tom S

"Tom S" > wrote in message
et...
>
> "Paul E. Lehmann" > wrote in message
> ...
>> Ray Calvert wrote:
>>
>>> I agree Tom. That is why I do not use a refractometer. Hydrometers are
>>> much cheaper. A refractometer is great in the field for checking grapes
>>> but even then you need to check the batch and a hydrometer is the way to
>>> go
>>> IMHO.
>>
>> If that is the case, why then, do you suppose that brix measurement is
>> the
>> standard measurement used pre-harvest and at harvest in the wine industry
>> and NOT SG?
>
> Specific gravity readings include _all_ dissolved solids, including
> whatever acids are present, and are therefore inherently inaccurate for
> measuring sugar. E.g., a juice at 23° Brix and 1.0 gram TA/100 ml will
> read 1.098 S.G. (24° Brix). Refractometers measure _only_ the sugar, so
> render a more accurate measurement.
>
> They're also a lot more convenient and rugged for field use.
>
> Tom S
>

I agree that the refractometer is definitely the way to go in the field.
Very convenient. Are you sure that it ONLY measures sugar though? We know
that alcohol has a huge effect on it which is one of the reasons it is not
used after fermentation starts. I suspect that dissolved gas has a big
effect. And I wonder if other chemicals in the juice will effect it. It
may be more accurate that a hydrometer. I am just not sure. If alcohol
effects it more that alcohol effects a hydrometer, then maybe other
chemicals effect it badly as well.

I will say it is considered bad practice in science to measure a parameter
with one tool at the start of a process and with a different tool at the end
unless the tools can be calibrated. But then you can calibrate the
hydrometer and the refractometer by measuring with both at the start and
deciding which you are going to trust. If it is the refractometer, then you
need to determine the difference and adjust the final reading in a similar
way.

Ray Calvert wrote:

>
> "Tom S" > wrote in message
> et...
>>
>> "Paul E. Lehmann" > wrote in message
>> ...
>>> Ray Calvert wrote:
>>>
>>>> I agree Tom. That is why I do not use a refractometer. Hydrometers
>>>> are
>>>> much cheaper.

Unless you are a clutz like me and break them constantly.


>>>> A refractometer is great in the field for checking
>>>> grapes but even then you need to check the batch and a hydrometer is
>>>> the way to go
>>>> IMHO.
>>>
>>> If that is the case, why then, do you suppose that brix measurement is
>>> the
>>> standard measurement used pre-harvest and at harvest in the wine
>>> industry and NOT SG?
>>
>> Specific gravity readings include _all_ dissolved solids, including
>> whatever acids are present, and are therefore inherently inaccurate for
>> measuring sugar. E.g., a juice at 23° Brix and 1.0 gram TA/100 ml will
>> read 1.098 S.G. (24° Brix). Refractometers measure _only_ the sugar, so
>> render a more accurate measurement.
>>
>> They're also a lot more convenient and rugged for field use.
>>
>> Tom S
>>
>
> I agree that the refractometer is definitely the way to go in the field.
> Very convenient. Are you sure that it ONLY measures sugar though? We
> know that alcohol has a huge effect on it which is one of the reasons it
> is not
> used after fermentation starts. I suspect that dissolved gas has a big
> effect. And I wonder if other chemicals in the juice will effect it. It
> may be more accurate that a hydrometer. I am just not sure. If alcohol
> effects it more that alcohol effects a hydrometer, then maybe other
> chemicals effect it badly as well.

Alcohol effects a hydrometer in a big way. That is why it is used. I am
not sure you can say that alcohol affects a refractometer more.

>
> I will say it is considered bad practice in science to measure a parameter
> with one tool at the start of a process and with a different tool at the
> end
> unless the tools can be calibrated.


Probably true but the following formulae developed by UC Davis (taken from
another poster a few years ago) allows one to pretty darn accurately
convert Brix to SG.

SG = (brix + 223.45) / 224.72

If you want to calculate alcohol produced you can just convert your initial
brix to SG, take your final SG reading with your hydrometer and then use
your formulae of choice to calculate alcohol produced.



> But then you can calibrate the
> hydrometer and the refractometer by measuring with both at the start and
> deciding which you are going to trust. If it is the refractometer, then
> you need to determine the difference and adjust the final reading in a
> similar way.