I had the exact same experience, 'cept in reverse. Got my juice home
and found it to be 1.8º Brix _higher_ than the vineyard reported.

In my case, perhaps the cold settling/clarifying of the juice in the
tanks caused some settling to occur. Perhaps the sugar drops in the tank
and concentrates. If so, then when they tapped the juice into my vessel,
its sugar content was slightly higher than when first tested. Just an
uneducated guess.

Or it could just be a calibration issue... I don't know. ~2º variance
seems a lot. I'm working with a hydrometer while the vineyard is working
with a refractometer.

-Paul

"Negodki" > wrote in message
...
> "Ken Anderson" > wrote:
>
> > Mine's ATC. Stood in the garage and calibrated at probably 60 ambient.
In
> > any event, I doubt you'd get a difference of 1.5 to 2.0 due to poor
> > calibration. Could my chintzy refractometer be that inaccurate? Do folks
> > ever take their refractometers with them to the juicehouse, so as to
check
> > the Brix for themselves?
>
> 'Twas just a suggestion. In a recent thread, someone complained about an
> even larger discrepancy between the refractometer and hydrometer readings,
> and (lack of proper) calibration was one of the possibilities cited.
>
> I have no experience with "juicehouses", but I know that by the time I get
> my grapes home from the vineyard (about a two hour drive in hot weather),
> they are always consistently lower by 2-3º Brix from that claimed by the
> grower --- and I know him to be an honest person. I have no explanation
for
> this, except that I use a cheap hydrometer and he uses a (very expensive)
> refractometer.
>
> But why are you buying juice with such a low brix (15-17) in the first
> place?
>
>