Hach-Lange LZV936 - DR 6000 Brewery Analysis software - Handbuch (Seite 32)

English 32
8. Add 0.5 mL of solution 2 to each flask and heat both reagent
flasks for 30 min in a boiling water bath (during the first 5 min stir
well with a glass rod).
9. Take out the glass rods, rinse with a little solution 1, maintain the
reagent flasks at 20 °C (68 °F) and fill with solution 1 to 25 mL.
10. Measure the extinction of the solution in a 10 mm rectangular
cuvette at 550 nm against an equivalently treated blank value
(10 mL dist. H
2
O instead of beer).
Results specifications
In mg/L without decimals
Accuracy
r = 9
Standard values
50–70 mg/L depending on raw materials and technological measures;
with stabilization with PVPP correspondingly less.
Literature
MEBAK brew-technical analysis methods, 4th edition 2002, Volume II, P.
109 et seq
Procedure for anthocyanogens
1. Prepare the blank value and the samples according to the work
procedure.
2. Select STORED PROGRAMS > SELECT BY NUMBER.
3. Enter the number 2005 for the program "Anthocyanogens". 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.
Beer color (spectrophotometric EBC method)
Principle
This method eliminates the subjective influences of the human eye and
differences in color impression with comparison of samples with a color
standard. This technical method is considered the official reference
method.
The extinction is measured in a 10 mm rectangular cuvette at a
wavelength of 430 nm. The color in EBC units is derived by converting
with a suitable factor.
Application area
Operating worts, beer, liquid malt substitutes of any type
Measurement range
0–60 units