"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