Hey Bill, Joe,

Clinitest isn't specific for glucose--it'll detect any reducing
sugars (including 5 membered ones, I think). But not sucrose.

The problem with using a diabetic's meter to test RS is that it
won't work. Depending on your yeasts, it can be the case that the
yeast will eat all of the glucose and leave all the fructose. You
can have (I've had it!) a wine with 1% fructose and NO glucose (had
to feed it glucose to get it going again) which will test as
absolutely dry with a diabetic's meter.

Dave, diabetic for 40 years now and wishing for a cheap easy test for
residual sugar.

William Frazier ) wrote:

Joe Sallustio wrote "My reds almost always come up as 0.3 or .0.4 RS and
they sure seem dry.
I was wondering if the color or phenol in red may affect Clinitest."

Interesting point Joe. I haven't tested for RS with Clinitest but some of
my wine club friends do. If Clinitest is specific for glucose and we are
testing wine containing at least some intact sucrose there may be a problem.
I've been playing around with a diabetic Glucometer Elite tester as an
alternative to Clinitest (some wine club members make sparkling wines and
are especially concerned with RS). The method I've been using calls for
acid treatment of the wine sample to hydrolyze sucrose to glucose and
fructose. The meter then reads glucose and I multiply the answer by a
factor to arrive at RS. You would think that sucrose in wine would
hydrolyze to glucose and fructose due to the low pH. But, I get very
different RS results with and without the acid treatment. You might look
into this as part of the problem you've been having with Clinitest.

Bill Frazier
Olathe, Kansas USA








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Dave
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Dave Breeden