Wort Boiling

Question 1

What are the 9 key functions of boiling?

Answer 1

Inactivation of malt enzymes
Sterilization
Concentration of wort
Development of color/flavor
Isomerization of hop compounds
Precipitation of protein/polyphenols
Volatilization of neg compounds
Acidification
Activation of foam stabilizing proteins

Question 2

How to calculate the required mass of steam (kg) for evaporation

Answer 2

Required mass of steam = (Volume hL x 1.017 x target evaporation % x 65) / target boil time

Question 3

What can cause lower than expected boil off?

Answer 3

Fouling, flailed control valve, leaks

Question 4

What causes proteins and polyphenols to coagulate in boil?

Answer 4

their 3D shape and charges change so that they no longer react with water molecules (hydrophobic)

Question 5

What is a good level of sediment from kettle finings?

Answer 5

Typically 5 mL/L

Question 6

What do gallotannins do?

Answer 6

They are polyphenols that interact with nitrogenous material in the boil

Question 7

Name 4 boil process aids

Answer 7

K-carrageenan, gallotannins, Silica sol, PVPP (Polyvinylpolypyrrolidone)

Question 8

What is DMS flavor threshold?

Answer 8

30-50 ug/L

Question 9

What DMS precursor is converted by reduction?

Answer 9

Dimethyl Sulphoxide (DMSO)

Question 10

How does thermal load affect finished beer?

Answer 10

Reduces flavor stability and foam potential

Question 11

What Maillard product can be measured to indicate thermal load?

Answer 11

2-furfural (low volatility)

Question 12

What are 2 foam positive proteins from the boil?

Answer 12

Protein Z (becomes glycated–carb attached)
LTP1 (becomes hydrophobic when denatured)

Question 13

What type of wort heater preheats wort as it runs into kettle?

Answer 13

Pre-run vessel

Question 14

How to calculate the amount of energy required to raise the temperature of a mass of substance?

Answer 14

q = M x Cp x (T2 - T1)
q in kJ
Cp is specific heat capacity kJ/kg C or K

Question 15

What unit is 1000m kJ

Answer 15

MJ

Question 16

How to convert MJ to kW

Answer 16

Divide by 60 (s) and multiple by 1000

Question 17

What is the specific heat of vaporization (kJ/kg of water)

Answer 17

2257

Question 18

What are the three types of boiling/heat transfer?

Answer 18

Film Boiling, Forced Convection and Nucleate Boiling

Question 19

What is wort flow composed of liquid and vapor bubbles called?

Answer 19

Two phase flow

Question 20

What type of wort flow does an internal calandria rely on?

Answer 20

Thermosiphon

Question 21

What type of wort heating involves superheated water at 120 C?

Answer 21

Hydroboiling

Question 22

What major improvements were made to modern external calandrias?

Answer 22

Looped tubes for greater contact time and back pressure to increase temp

Question 23

What’s a major commercial external calandria?

Answer 23

Briggs Symphony

Question 24

Notable commercial internal calandrias

Answer 24

GEA Jetstar, Krones Stromboli, Ziemann Holvrieka

Question 25

What is the boiling method that employs stages of increasing and decreasing pressures to increase wort temp and create vapor when decreased?

Answer 25

Dynamic Low Pressure Boiling

Question 26

How can wort stripping affect energy usage?

Answer 26

Up to 50% less energy for boiling

Question 27

What device collects energy as steam is condensed back to water?

Answer 27

Vapor condenser

Question 28

What technology allows steam from kettle to be recaptured and compressed to supply heat back to kettle?

Answer 28

Mechanical Vapor Recompression

Question 29

What technology allows steam from kettle to be recaptured and compressed to supply heat back to kettle, while supplying additional steam to transform it to usable steam?

Answer 29

Thermal Vapor Recompression