1st mid term

Question 1

Increasing particle size in order to speed up beer clarification can be accomplished by

Answer 1

use of fining agent

Question 2

Isinglass consists of 70 % of the protein gluten

Answer 2

false

Question 3

Stokes law units
g
n
v
d
p

Answer 3

g= m/s2
n= kg/m/s
v= m/s
d= m
p= kg/m3

Question 4

Auxiliary finings have ____ charge at beer pH.

Answer 4

negative

Question 5

Which of the following is not an advantages of Hollow Fibre Membrane Filters over DE filters?

Answer 5

low capital investment

Question 6

Silica gel has ___ influence on foam stability.

Answer 6

No influence

Question 7

PVPP

Answer 7

-completely removed by filtration
-has no negative effect on beer foam and flavour

Question 8

Sterile filtration is an alternative to

Answer 8

pasteurization

Question 9

Absolute removal rating of a membrane indicates

Answer 9

the largest opening in the filter element

Question 10

D value is the time needed at a given temperature to

Answer 10

inactivate 90% of all viable microbial population

Question 11

beer spoilage organisms are not

Answer 11

pathogenic

Question 12

Sterilization is an absolute heat treatment process and will produce

Answer 12

a fully stable product.

Question 13

What are two practical options for speeding up beer clarification based on Stoke’s law?

Answer 13

-increase particle size
-increase force of gravity

Question 14

Cellulose
DE
Perlite

Answer 14

Cellulose - obtained from wood
DE - fossilized skeletons from algae
Perlite - volcanic origin

Question 15

Darcys equation
K
L
p
u
A
Q

Answer 15

K - filter bed permeability
L - Height of filter bed
p- differental pressure
u - viscosity
A - constant cross section area
Q - total liquid percolating in unit time

Question 16

Bubble point test gives an indication as to

Answer 16

the size of the largest pores in the membrane.

Question 17

Pasteurization was developed in the

Answer 17

19th century

Question 18

The aim of beer stabilization is to prolong the product shelf life through

Answer 18

the deactivation of Microorganisms and
enzymes.

Question 19

Hydrogels have ___ water content than Xerogels.

Answer 19

higher

Question 20

Removal efficiency of sterile filter is defined as the titre reduction. Tr = (No of organisms at inlet/No of organisms at
outlet). If the number of bacteria at inlet is 100 billion, and the number of bacteria at outlet is 100, determine Tr
value of the filter.

Answer 20

10^9

Question 21

The viscosity of a liquid ____ with increase in temperature.

Answer 21

increase

Question 22

Nominal

Answer 22

• Gives no indication of the sizes of the particles which
  have passed through the filter

Question 23

Beta rating

Answer 23

measures the total particle count change across the filter at several different particle sizes