This
is the section where certain vital parameters are checked during and after brewing.
It is the analysis done to checkmate the consistency of the quality of the
product starting from the intake of the raw materials through all stages of
brewing and packaging, until product leave the to the consumers. The process
analyses carried out are as follows;
1. Foam stability
Apparatus:
Nibem
foam stability tester, foam flasher, standard glass curvette(cylindrical type),
CO2 cylinder.
Procedure:
i)
Attemperate
the beer to 200C.
ii)
Open
the bottle and connect the flasher under the gas cylinder with pressure exactly
0.8 bar. Fill glass. To ensure collection of beer not foam, the flasher outlet must be positioned 1cm over the bottom of the
cuvette.
iii) After the first
foam has flown over the glass, close the cap of the flasher.
iv) Place the glass
under the tester and press start. After the foam has collapsed 3cm, the
apparatus is shut off. The value shown represents the head retention in
seconds.
2.
Bitterness:
This measures the iso alpha acid
(bittering substances in the
beverages)
apparatus:
UV
spectrophotometer, mechanical shaker with vertical amplitude, volumetric glass,
Procedure:
i)
At
temperate the sample to 20C by placing in 20c water bath.
ii)
Degas
by shaking gently at first and then vigorously until gases no longer escape.
[Avoid loss of foam and allow foam to collapse back into the sample because
foam is richer in bitterness than the liquid}
iii) Measure 10ml of
the degassed sample into a 100ml volumetric flask.
iv) Add 1ml of 3N
HCL acid to it {this will help to bring up the PH.)
v)
Add
20mls of 150-octane {this will separate the iso-alpha acid from other component
of the beverages)
vi) Close the flask with
a glass stopper and clamp on the mechanical shaker to shake vigorously for 5
mins.
vii)
After
shaking, it will have two lagers with the bittering substance on top.
viii)
Put
in the dark cupboard for 5 mins {because it is photo reactive}.
ix) Measure the
bitterness at wavelength of 275nm and multiply by 50.
2.
Turbidity:
This is the measure of the degree of
clarcty of the beverages.
Apparatus: Haze meter,
curvette {100ml}, ice bath keiselgur powder.
Procedure:
(1)
Filter
the sample using the filter {powder} {keiselgur}.
(2)
Rinse
the curvette with the sample twice and fill about three quarter with the
sample.
(3)
Place
in the ice bath for 3 mins.
(4)
Place
in the hazemeter comparment and press start to read.
3. Colour:
The colour of both beer and malted
drinks are measured at ambient temperatures using the spectrophotometer at
wavelength 430nm.
Apparatus:
UV
spectrophotometer, filter paper, conical flask.
Procedure:
1.
Degas
the sample and filter to obtain clear solution
2.
Zero
the machine with distilled water by measuring 1ml of distilled water into the
curvette and press measure blank.
3.
Take
out the curvette and replace with sample. Wipe the body thoroughly and place in
the compartment. Close the lid.
4.
Read
off and multiply by 25 to obtain colour value.
5.
Apperant extract {Ea} and alcohol content:
This measures
the amount of unfermentable sugars in the beer while the alcohol measures the
level of alcohol in v/v contained in the beer.
Apparatus:
Alcohol
machine {measures the Ea, alcohol, OG. and density} filter paper, water bath,
conical flask, funnel.
Procedure:
(1)
Attemperate
the sample to 20˚C {put it into 20˚C water bath for some
minutes}.
(2)
De-gas
the sample {by shaking it and allow allow the gas to evaporate}.
(3)
Filter
using the CBR filter powder {keiselgur}.
(4)
Put
sample into two tubes and insert into the auto sampler of the alcoholizer and press start.
(5)
Read
the alcohol by volume and the apparent extract.
(6)
Original gravity:
This is the
measure of the gravity of sugar present in the beverages.
Apparatus:
Alcolizer machine, filter paper, filter
funnel, conical flask and keiselgur powder.
Procedure;
1.
Attemperate
the sample to 20oc and degas
2.
Filter
the sample with filter paper and keiselgur powder.
3.
Pour
a portion of the sample into two tubes and insert into the auto sampler of the
alcolizer and press start.
4.
Read
off the OG result.
7. PH
This measures the acidity alkalinity of the
product.
Apparatus:
PH meter,
cuvette,
Procedure:
(1)
Rinse
the PH electrode with the sample twice.
(2)
Place
the PH electrode in the sample and allow beating.
(3)
When
stop beating take the reading .
8. CO2 check
This measures
the level of CO2 in the product.
Apparatus:
CO2 Gohelt meter.
Procedure:
1.
Sterilize
the sampling point of the BBT with ethanol.
2.
Connect
the mouth of the CO2 meter to the sampling tap and allow the sample to flow out
of the hose.
3.
Press
measure on the meter, As it flows out it measures the CO2 level in Mg/l
9 Dissolved
oxygen
This measures the amount of O2 that is
dissolved in the beverages.
Apparatus:
Obisphere,
conical flask,
Procedure:
(1)
Sterilize
the sampling point of the BBT with ethanol
(2)
Insert
one end of the hose into the tank and the other end into conical flask.
(3)
Open
the tap and press measure on the obisphere. As it is flowing from the tank to
the conical flask, it measure it in mg/L.
The table below shows the norms
of the above mentioned parameters in the beverages. This norm helps to
regulate/maintain the layed down standard of the production.
|
Parameters
|
Heineken brand
|
Star brand
|
Gulder brand
|
Maltina brand
|
Amstel malta
brand
|
|
PH
Turbidity
Bitterness
colour
OG
AE
Foam {Sec}
Co2
02
alcoho (v¤v)
alcohol (v¤w)
|
4.25-455
0-0.6
17.5-20.5
6-8
11-11.6
1.8-2.2
250-350
0.51-0.55
0-50
4.8-5.2
3.77-4.04
|
4-4.3
0-0.8
18-22
7-9
11.5-11.9
1.7-2.2
200-300
0.48-052
0-50
4-0
0-0
|
4-4.3
0-1
23-27
6-8
11.4-11.8
1.4-2.2
200-300
0.48-0.52 0-50
5-5.4 4-4.4
|
4.7-4.9 0
13-17 200-250
14-14.4 0 200-350 0.52-0.56 0-50 4-0 0-0
|
4.7-4.9 0
11-15
200-250
12.6-13
0
200-350
0.52-0.56
0.-50
4-0
0-0
|