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GENERAL DESCRIPTION
2. GENERAL DESCRIPTION
The
HI83749
is an auto diagnostic microprocessor meter that benefits from Hanna’s years of
experience as manufacturer of analytical instruments.
The meter is especially designed for wine analyses and, beside turbidity measurements, it allows to
make tests to verify protein stability (e.g. Bentocheck).
The instrument compensates wine color to guarantee accurate readings during the vinification process;
also for the darkest red wine samples. The optical system, consisting of a tungsten filament lamp
and multiple detectors, assures long term stability and minimizes the need of frequent calibration.
Calibration can be anyway easily performed at any time in two, three or four points (<0.1, 15, 100
and 500 NTU-adjustable calibration points), using the supplied or user prepared standards.
The meter has all necessary GLP (Good Laboratory Practice) functions to allow maximum traceability of
data like a real time clock, log-on-demand (up to 200 measurements), and T.I.S. -Tag Identification
System to give all recorded data a location, time and date stamp.
The meter measures turbidity of samples from 0.00 to 1200 NTU (Nephelometric Turbidity Units) and
is USEPA compliant. In the USEPA measurement mode the instrument rounds the readings to meet
USEPA reporting requirements. It has a continuous measurement mode to verify the settling rate of
suspended matter, and a signal average (AVG) mode to accumulate multiple readings giving a final
average value. The AVG routine is particularly useful to measure samples with suspended particles
with different dimensions.
The
HI83749
has a user-friendly interface, with a large backlit LCD (Liquid Crystal Display). Acoustic
signals and displayed codes to guide the user step by step through routine operations.
This valuable splash proof portable turbidity meter is supplied in a rigid carrying case that offers
protection for harsh environments.
2.1. BENTOCHECK
The prevention of protein haze or deposit in bottled white wines is a universal concern and often a wine
needs to be stabilized before bottling. One commonly used stabilization agent is bentonite. Bentonite
is a volcanic clay earth type fining agent (like kaolin). It improves the clarity and stability of wine
but has also negative aspects because of the volume of lees formed, reduction of tannin and color.
Since there are different types and qualities of bentonite with different capacity of protein removal, it
is important to make laboratory trails with the same lot and wetting degree of the bentonite as that
will be used in the cellar.
Protein stabilization is normally not a problem in bottled red wines because of the relatively high
concentration of phenols that binds and precipitates with the instable proteins before bottling. Often
bentonite is added to red wines at a level of about 12 g/hL (1 lb/1000 gal), reducing colloidal
suspended particles thus improving membrane filterability.
Wines with low phenols contents, such as rose, light reds and whites should be checked for protein
stability before bottling. Hanna is offering a rapid test to verify the risk of future protein haze formation.
