This
section takes care of all the raw materials entering the brewery, the materials
used in brewing, the packaging materials as well as the fuel/oil used in
powering the engines. The analysis carried out on raw materials (malt, sorghum
malt, raw sorghum, maize grist) used in brewing are; moisture content analysis
and sieve analysis.
Moisture content analysis:
This
measure the amount of water contained in the grains.
Apparatus
Metal curvette, weighing balance, spatula, 130-140
oven.
Procedure:-
1. Grind the sample using the milling machine
2. On the weighing balance and weigh the empty metal
curvette
3. Measure 5g of
the milled grain into the metal curvettes and add to the initial weight of the
metal curvettes.
4. Then place in the 130oC-140oC
ovens and allow to stay for 3hrs.
5. After 3 hrs, put in the desiccator for 10 mins and
weigh the curvette again. The difference in wt gives the moisture of the
grains.
Sieve
Analysis:
This measures the fineness or coarseness of
the milled grains. When the grist is too fine or too coarse, it will pose a
problem during mashing and filtration processes
Apparatus
Retsch
Horizontal sieving machine, type 1000 equipped with a set of sieves with
diameters ranging from 1.25mm, 1.00mm, 0.56mm, 0.25mm and its bottom, weighing
balance, 4 small rubber balls and 4 small rubber cubes.
Procedure
1. Weigh 300g of the sample
2. Place 2 small rubber balls and rubber cubes
on each of the finest sieves.
3. Put the sample on the coarsest sieve of the
set, fasten the sieves in the machine and set to run for exactly 15 minutes at
rotation speed of 300rpm.
4. After 15mins,
then start reweighing the quantity of sample in each component of the sieve
making sure that you don’t loose any sample
After weighing the different components of the sieve,
then add the weight together and see if you can get 300g, which is the original
quantity you weighed, then convert the result from each component to
percentage, from the result, one can say whether is fine or coarse.
RETSCH SIEVING MACHINE
Fuel/oil
analysis includes;
− flash point
− Water content
− Temperature and specific gravity
Flash point:
Apparatus
Flash point tester, syringe, tissue paper, lighter.
Procedure;-
1. Set the temperature on the flash point tester by press
holding the temperature button
2. Introduce 1ml
of the sample into the sample cup.
3. Switch the gas
supply on and light with a lighter, press start to start ramping.
4. In every 1◦c rise in temperature it beeps and once it
does that, adjusts the shutter until it reaches it’s flashing point. Then read off.
FLASH POINT TESTER
Water content
This
measures the percentage of water in the fuel/oil.
Procedure:
1.
Add 20mls of
reagent A into a beaker
2.
Add 1ml of the
fuel/oil sample into it
3.
Add 1 sachet of
calcium hydride into the beaker and shake
4.
Transfer the
content of the beaker into the black bottom of the machine and press start
(shake vigorously for 10 mins and allow to read)
5.
Read off the
result (the water content should be ≤ 1٪)
Temperature and specific gravity
Procedure:
1.
Measure 300mls of
the sample into a measuring cylinder
2.
Insert the
thermometer and read off the temperature
3.
Insert the
hydrometer and read off the density (density/1000 will give the specific
gravity)
Bloom test
This is the analysis carried out on new
virgin bottles used in packaging of the beverages. This is to check if there is
any phenol ions residue that could be leaching out from the bottle.
Procedure:
1.
Measure 100mls of
distilled water into the bottle and shake
2.
pour into a
conical flask and add 3 drops of
phenolphthalein and shake
3.
If the colour
changes to pink, there is presence of phenol ions.
4.
Repeat for about
2 times on that same bottle, if there is a colour change, the bottle will be
rejected. Otherwise it is accepted.