jim wrote:
On Nov 28, 12:00 pm, "frederick ploegman"
wrote:
"jim" wrote in message

...

Hi Gene, alcohol is definitely less dense than water, but if a wine at
1.000 is not quite dry, why do they calibrate 1.000 with 0PA? Do you
see why I think it is confusing?
Jim
The scales on a hydrometer are like a snapshot. A picture of a
moment frozen in time. That picture is of a prepitch must with
no alcohol in it. Once alcohol enters the picture, the claibration
on the hydrometer is no longer valid. HTH

Frederick

Now that makes it all coherent for me, thanks Frederick!

Are you sure about that, Frederick?

My understanding is that alcohol doesn't affect the Specific Gravity
accuracy, but it does affect the correlation to "potential alcohol" and
"degrees Brix". The more alcohol, the bigger the skew error.

I'm aware of only three significant factors that cause errors in
specific gravity measurement of wine with a properly calibrated hydrometer.

First, bubbles in the solution cause buoyancy errors (that's why we spin
the hydrometer, to knock bubbles off of it). Second, suspended solids
(floating grape skins, etc.) which, if touching the hydrometer, cause
buoyancy errors. Third is temperature of the juice, for which we have
SG correction tables.

Am I missing something here?

Gene