© PCE Instruments
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Before you use the device, it must be calibrated. The sample must be prepared by filtering the
must. The first drops are discarded (to use our refractometers, the temperature of the sample
must be within a range of 20 ... 30 ºC and must never exceed 30 ºC). Now place 1 - 2 drops of
the sample on the prism. By moving the hinged lid slightly, the sample liquid can be distributed
evenly. Two measurements should be made.
After having the result in Brix (per cent in sucrose), you can calculate the alcohol content with
the help of a formula (valid for the range 15 ... 25 Brix):
% vol = (0.6757 x ºBrix) - 2.0839
or you can use the chart below, especially when the range is exceeded.
EXAMPLE:
With our refractometer, we measured a sample with a sugar concentration of 24.2 º Brix. If we
do not have any charts and want to determine the alcohol content, we have to apply the
formula:
% vol = (0.6757 x 24.2º) - 2.0839= 16.35 - 2.0839 = 14.31 % vol
If we have charts, we can look for the reading
24.2º
in the first column and get the
corresponding value of alcohol content in the last column. In our example for
24.2º Brix
, the
alcohol content is
14.28 % vol.
