Hach-Lange DR 5000 brewerie analysis, supplementary software LZV570 - Manual (Page 31)

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Working procedures
m. Measure the chloroform extract (prepared distillate) in a
40 mm rectangular cuvette at 460 nm against a blank value
solution obtained by following the above procedure but
using 300 ml H
2
O instead of the distillate.
3. Calibration values
a. Carry out steam distillation on phenol standard solutions
with concentrations between 0.02 and 0.1 mg/l (use
300 ml), then proceed as described above.
Results
The results are expressed in mg/kg to two decimal places (or in
mg/l in the case of beer)
Accuracy
Vc = ± 5% (repeat error)
Required values
Malts: < 0.2 mg/kg: no smoky taste to be expected.
Beers: < 0.03 mg/l: negligible effect in most cases.
The intensity of the smoky taste is partly dependent on the
composition of the beer. The specified lower limit therefore only
applies with reservations.
Literature
MEBAK Brautechnische Analysenmethoden 3rd Edition, Volume I
2.7.1 Procedure for measuring steam-volatile phenols
1. Prepare the samples and blank value solution as described in
the working procedure.
2. Select STORED PROGRAM s in the “Main Menu”. Select test
number 809 .
3. Insert blank value cuvette (see sample preparation) into the cell
compartment. Close the cell compartment. Touch ZERO .
4. Insert the sample cuvette containing the prepared sample into
the cell compartment and close the cell compartment. Touch
READ . The result is displayed.