Lesson 2 - Wort Separation Principles
This lesson deals with the principles of wort separation. Before wort separation, we have completed mash conversion. We will now need to separate the liquid wort from insoluble material. This is mainly the husks from the malt, known as spent grain. We will review the reasons why filtered wort must be clear, and how this affects wort quality. We will examine how the all-important grain filter bed is formed differently, by each of the three most common mash separation devices. These devices are: the lauter tun, the mash filter and the mash tun. We will investigate a typical wort collection profile, which ends with the removal of the spent grain.
Darcy’s Law describes filtration flow rate. We will assess both the variables involved, and what influences them. We will finally use Darcy’s Law to predict the relative flow rates of the three mash separation devices.
Lesson Sign-Off
This lesson dealt with wort separation and how Darcy’s Law can predict the different flow rates achieved by the three most common mash separation devices.
You should now be able to:
1. Outline the process objectives of wort separation.
2. Explain the role of the grain filter bed.
3. Understand how the grain filter beds are formed differently by the lauter tun, mash filter and mash tun.
4. Produce a typical wort collection gravity profile with values for gravity and volume. Include the following within this: strong worts, sparge, sparged worts, weak worts and last runnings.
5. Describe the removal and disposal of spent grain.
6. Define Darcy’s Law for calculating the filtered wort flow rate of a wort separation device; explain each of the variables involved.
7. Explain why wort viscosity can vary, and how it affects filtered wort flow.
8. Provide typical grain bed loadings for the different wort separation devices, and then calculate their relative impact on filtered wort flow.
9. Demonstrate how the different milling requirements for different separation devices affect grain bed permeability; evaluate the impact on filtered wort flow.
10. Explain why a wort separation device has to operate with a low differential pressure limit; describe the consequence for filtered wort flow.
11. Demonstrate, using Darcy’s Law, the relative flow rates for each mash separation device for a set grist charge.
A self-assessment lesson will now follow. This will give you the opportunity to determine the level to which you have met these learning outcomes.