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The
HI 83748
is an auto-diagnostic portable microprocessor meter that benefits from Hanna’s
years of experience as a manufacturer of analytical instruments. It has an advanced optical system
based on a special tungsten lamp and a narrow band interference filter that allows most accurate
and repeatable readings. All instruments are factory calibrated.
The auto-diagnostic feature of this meter ensures always optimal measurement conditions to
ensure most precise readings. The light level is automatically adjusted each time a zero-measurement
is made, and the temperature of the lamp is controlled to avoid overheating.
GENERAL DESCRIPTION
Tartaric acid and tartrate are playing an important role in the stability of wines. They can be present in
wine and juice in various forms, like tartaric acid (H
2
T), potassium bi-tartrate (KHT) or calcium tartrate
(CaT). The ratio of these depends mainly on the pH of the wine. The percent of tartrate present as
bitartrate (HT-) is maximum at pH 3.7.
The formation of crystalline deposits (tartrate casse) is a phenomenon of wine aging but does not meet
customer acceptance. It is therefore important to test for, and to reduce potential of bottle precipitation;
for example by adjusting the pH of the wine that significantly influences the potential of casse formation.
Potassium concentrations in wine can range from 600 to 2500 ppm in certain red wines. Although the
potassium bi-tartrate is soluble in water, alcohol and low temperatures decrease its solubility. Especially
during the alcoholic fermentation potassium bi-tartrate becomes increasingly insoluble resulting in
super-saturation and precipitation. The KHT stability can be restored by chilling (with or without
seeding). Wines with initial pH values below 3.65 can show a reduction in pH during cold stabilization
because of generation of one free proton for each KHT precipitated. The pH may drop as much as 0.2
pH units. For wines at higher pH than 3.7 the pH shifts to a higher pH.
Calcium concentrations can range from 6 to 165 ppm and may complex with tartrate or oxalate to
form crystalline precipitates. Calcium tartrate instabilities occur normally from 4 to 7 months after
fermentation and are temperature independent.
Sulphates, proteins, gum and poly-phenols can form stable complexes with tartrate thus inhibiting
case formation. The complexes are mainly between poly-phenols and tartaric acid in red, and proteins
in white wine. This explains why, as pigment polymerization occurs, the holding capacity of tartaric
acid diminishes, resulting in delayed casse. The sulfate instead does complex with potassium from
50% in white wines up to 100% in red ones.
Tartaric acid concentrations in wine range normally from 1.5 to 4.0 g/L. This acid concentration may
not be confused with total or titratable acidity of wines that are often expressed in tartaric acid content
too. Although it is the tartaric acid that is the predominantly present acid (up to 60% of the total
acidity), others like malic, citric and several volatile acids do give a significant contribution to total
acidity.
SIGNIFICANCE OF USE
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Recommendations for Users
Before using these products, make sure that
they are entirely suitable for your specific
application and for the environment in which
they are used.
Operation of these instruments may cause
unacceptable interferences to other electronic
equipments, this requiring the operator to take
all necessary steps to correct interferences.
Any variation introduced by the user to the
supplied equipment may degrade the
instruments' EMC performance.
To avoid damages or burns, do not put the
instrument in microwave ovens. For yours and
the instrument safety do not use or store the
instrument in hazardous environments.
CE DECLARATION OF CONFORMITY
HI 83748 is warranted for two years against defects in workmanship and materials when used for
its intended purpose and maintained according to the instructions.
This warranty is limited to repair or replacement free of charge.
Damages due to accident, misuse, tampering or lack of prescribed maintenance are not covered.
If service is required, contact your dealer. If under warranty, report the model number, date of
purchase, serial number and the nature of the failure. If the repair is not covered by the warranty,
you will be notified of the charges incurred.
If the instrument is to be returned to Hanna Instruments, first obtain a Returned Goods Authorization
Number from the Customer Service Department and then send it with shipment costs prepaid.
When shipping any instrument, make sure it is properly packaged for complete protection.
To validate your warranty, fill out and return the enclosed warranty card within 14 days from the
date of purchase.
Hanna Instruments reserves the right to modify the design, construction and appearance of its products
without advance notice.
WARRANTY
