"Negodki" wrote in message
...
"LG1111" wrote:

When analying freshly crushed grapes, even after I strain the juice, I
find a
significant difference between the Brix levels reasured by a
refractometer
and
when measured by a hydrometer. I suspect that it is due to suspended
solids,
but which should I go by?

The refractometer measures 22.2 and the hydrometer measures 23.5 on a
red
must,
with a SG of 1.095.

On a white, the refractometer measures 18.5 and the hydrometer measures
22,
with a SG of 1.088.

The problem is that if I go by the refractometer reading on the white, I
should
add some sugar.

Any suggestions? I hate to add sugar unless I have to.

First, make sure that the refractometer is calibrated for the temperature
of
your must, and/or adjust the reading for the temperature. Most wine
hydrometers are calibrated at 59ºF. There should be a table that came with
the hydrometer that tells the amount to add or subtract for different
temperatures. If not, tables for brix and sg adjustments were posted
recently.

Second, make up a 20º Brix solution (weigh 20 grams of sugar into a
measuring cup, add water to 100 ml, and stir well). Test the Brix of the
solution with both methods. Decide which is the more accurate, and use it.

Brix is defined as grams of sugar per 100 GRAMS of liquid. A 20 Brix
solution can be easily made by adding 20 grams of sucrose to 80 milliliters
of water. See Ough "Winemaking Basics," page 260.
lum