Hach-Lange LZV936 - DR 6000 Brewery Analysis software - Handbuch (Seite 29)

English 29
Results specifications
In mg/L without decimals
Accuracy
s = ± 9
Standard values
Beer: 150–200 mg/L
Literature
MEBAK brew-technical analysis methods
4th edition 2002, Volume II, P. 107 et seq
Procedure for total polyphenols
1. Prepare the blank value and the samples according to the work
procedure.
2. Select STORED PROGRAMS > SELECT BY NUMBER.
3. Enter the number 2002 for the program "Total polyphenols".
Confirm with OK.
4. Press START to start the program.
5. Enter the blank value (see sample preparation) and press ZERO.
6. Insert the analysis cuvette with the prepared sample and press
READ.
The result is shown on the display.
Note: In order to analyze further samples, repeat the procedure from
step 6.
Reducibility (spectrophotometric method)
Reducibility is a measure for the fast-reducing substances present in the
beer. Reducers occur in the beer in relatively small quantities, but have
great significance in the chemical, physical, and biological properties as
well as the taste stability of the beer.
Principle
Reducers reduce a certain amount of Tillmann's reagent (2,6-
dichlorophenol indophenol, DPI) within a certain time span. The
decoloration of the reagent is spectrophotometrically measured and
calculated.
Measurement range
0–100