Point of reflection – reconvene

Question 1

What is the relationship between the surface area A of the lauter tun and the mash tun?

Answer 1

A of the lauter tun is 2.5 times greater than the mash tun

Question 2

What is the effect of the larger surface area A on grain bed loading in the lauter tun?

Answer 2

Grain bed loading is 2.5 times lower

Question 3

How does the resultant grain bed depth L of the lauter tun compare to the mash tun?

Answer 3

L is 2.5 times shallower

Question 4

What type of mill is used for the lauter tun, and what is its effect on grist?

Answer 4

A six-roller mill is used, creating a finer grist with a lower husk fraction

Question 5

What is the impact of a lower husk fraction on grain bed permeability K in the lauter tun?

Answer 5

K will be lower than for the mash tun

Question 6

What effect does a thinner mash and higher wort temperature have on wort viscosity for the lauter tun?

Answer 6

Produces a lower viscosity wort which favours lauter tun flow

Question 7

What is the water to grist ratio for the lauter tun?

Answer 7

3.2 L/kg

Question 8

Fill in the blank: Darcy’s Law predicts relative flow rate as Q = K × DP × A / ________ × L

Answer 8

µ

Question 9

What is the grain bed permeability K for the mash tun?

Answer 9

275

Question 10

What is the grain bed permeability K for the lauter tun?

Answer 10

87

Question 11

What does the lauter tun use to improve grain bed permeability?

Answer 11

Rakes

Question 12

What materials are commonly used to construct a lauter tun?

Answer 12

Copper or stainless steel

Question 13

What ensures that the lauter tun cannot be pressurized during filling?

Answer 13

The flue pipe (vent stack)

Question 14

How are wort outlets spaced in the lauter tun?

Answer 14

Approximately every 1 - 2 m²

Question 15

What is the role of the flow throttling valve known as a ‘tap’ in the lauter tun?

Answer 15

To ensure even outlet flows

Question 16

True or False: The modern lauter tun relies on gravity flow to an open collection trough.

Answer 16

False

Question 17

What is the purpose of the maze of pipework underneath the lauter tun?

Answer 17

To ensure even flow from each outlet

Question 18

What is the false floor in the lauter tun made of?

Answer 18

Segmented plates or wedge wire

Question 19

What is the maximum width of the milled slots in the false floor?

Answer 19

0.7 mm

Question 20

What is the void depth under the false floor?

Answer 20

25-50 mm

Question 21

What is the DP limit that must not be exceeded for the false floor?

Answer 21

0.1 bar

Question 22

How does the mash enter the lauter tun to minimize air entrainment?

Answer 22

At false floor level

Question 23

What is the rotation speed of the internal rig with attached rakes in the lauter tun?

Answer 23

Approximately 0.1 rpm

Question 24

What is the minimum spacing required between rakes to avoid bulldozer action?

Answer 24

160 mm

Question 25

What temperature is the sparge water applied at during the sparging process?

Answer 25

76-78˚C

Question 26

What is the purpose of the sparge system in the lauter tun?

Answer 26

To rinse the spent grain bed of its residual extract

Question 27

What happens to the spent grain after wort collection?

Answer 27

It is removed using the rig

Question 28

What is the time frame for graining out in a high-volume brewing unit?

Answer 28

10-15 min