Lesson 5 - Wort Separation Technology SAQ
This lesson allows you to test yourself on the material covered in Lesson 4 on ‘Wort Separation Technology’ and determine the level to which you have attained the outcomes.
Suggested Response - Q7
**With reference to wort separation steps and typical cycle times, explain why the mash filter time to process 10 t of malt is around 24% less than that required by the lauter tun.
Response:
The cycle times for the two units need to take account of the liquid volumes being processed:
|
|
Lauter Tun |
Mash Filter |
|
Mash L/kg (hL/10 t) |
3.2 (320) |
2.7 (270) |
|
Sparge L/kg (hL/10 t) |
4.0 (400) |
2.8 (280) |
|
Total water (hL/10 t) |
(720) |
(550) |
Cycle times of process stages in min:
|
|
Lauter Tun |
Mash Filter |
|
Underlet |
3 |
n/a |
|
Filling |
10 |
5 |
|
First worts recirc. |
6 |
n/a |
|
Strong worts |
40 (including one deep bed rake) |
27 (including pre-compression) |
|
Sparged worts |
65 |
53 (including final compression) |
|
Bed draindown / empty |
5 |
5 |
|
Spend grain discharge |
15 (including under-floor jetting) |
20 |
|
Total cycle time |
144 |
110 |
The mash filter can process a mash in 24% less time than the lauter tun.
From start of mash transfer, to start of collecting strong worts, the lauter tun requires 19 min compared to the mash filter which requires just 5 min. The mash filter fills rapidly and does not require the settling of the grain bed, or the first worts recirculation of the lauter tun.
The lauter tun strong worts collection is slower at 40 min. The thicker mash for the mash filter results in higher viscosity wort, which will reduce flow. However, the lower volume of strong worts, and the much higher surface area, still allows the mash filter to achieve strong wort collection in 27 min.
The lauter tun sparged worts collection is longer at 65 min. This is despite ramping up flow rate approximately three-fold in response to reducing gravity and viscosity. The sparge volume of the mash filter is significantly lower. The mash filter deliberately reduces its flow rate during sparge to achieve the extraction with lower water volumes. It still achieves this in 53 min, less time than the lauter tun.
Spent grain discharge is nowadays fairly similar for the two units operating in rapid batch brewhouses.
For a 10 t batch of malt, the lauter tun brew uses 720 hL of water; some 30% more than the 550 hL used by the mash filter. The mash filter produces lower volumes, which are at a higher gravity. and therefore higher viscosity. The higher viscosity will reduce wort flow rate/unit of surface area, but this is more than compensated for by a six times greater surface area compared to the lauter tun.