On 11/10/03 12:38 PM, in article 3fafdbd4$0$6960$afc38c87@, "Jack
Schmidling" wrote:

Got my $39 refractometer and can't believe these things used to cost
hundreds.

I was hoping someone would crunch my numbers and see if they make sense.

I took a 10 ml sample of raspberry wine and measured:

Alcohol: 15% on alcolimiter or whatever that glass thing is called.
Brix: 11% on refractometer

I then boiled it for 5 minutes, reducing it about 50% then added distilled
water to 10 ml.

Refractometer then read 6% and the alcohol read 1%

I was surprised to see the brix drop so much but I have no feel for this.

js

For your alcohol measurement, are you talking about a vinometer? If so, I
think they do not give good numbers if there is sugar present. Now, the
refractometer --- it is also affected by the alcohol present. Thus, the
numbers will be off.

--
Greg Cook
http://homepage.mac.com/gregcook/Wine

(remove spamblocker from my email)

On 11/10/03 10:35 PM, in article 3fb0670f$0$6952$afc38c87@, "Jack
Schmidling" wrote:


"Greg Cook"

For your alcohol measurement, are you talking about a vinometer?

Roger.

If so, I think they do not give good numbers if there is sugar
present.....

I understand. It is just a reference point. Having said that, I checked
some Taylor port with it and it read 18% just like the label said.

Hmm, these are calibrated on dry wines. To be honest, I have never used them
so I don't can't say much more than I have read. Maybe you could test it out
with some wines of different alcohol/sugar contents and see how off the
calibration is? This may not be linear.


Now, the
refractometer --- it is also affected by the alcohol present. Thus, the
numbers will be off.

You obviously did not read my message. I boiled the sample for 5 minutes to
remove the alcohol and added distilled water to make the sample up to
original volume.

I certainly did read your post. You were surprised to see the numbers change
so much when compared BEFORE and AFTER boiling. Of course your refractometer
reading will be different after boiling. The alcohol is gone and you have a
different amount of water present. How much light is refracted will depend
on all the components -- changing ethanol to water is a large change in the
refractive properties of the solvent, which is how you are indirectly
measuring sugar content.

Recently someone posted a link (can't find it now of course :-) with
informatinon on how to correct for these errors. It was recent in one of the
refractometer threads.

--
Greg Cook
http://homepage.mac.com/gregcook/Wine

(remove spamblocker from my email)