Lesson 8 - Yeast Management
This lesson will explore the methods that are used to measure yeast’s concentration and to assess its health. We will then go on to describe how this knowledge underpins the methods used to store and handle yeast in the brewery.
Yeast Viability
A simple measure to gauge the condition of yeast is simply to test if cells are living or dead. We all know that, just like us, yeast cells have a finite lifespan. It is normal, therefore, to find some dead cells in the population. If the proportion of dead cells is greater than we would expect, it indicates that something is wrong.
What is viability?
Viability is defined as the proportion of living cells in a population. On the surface, this is a fairly simple concept – viable therefore means something that is living.
Figure: Image of yeast cells stained with methylene blue
This is true, of course, but when we are discussing yeast, we need to think about this a bit more deeply.
How would you define a viable yeast cell? Think about this, especially from the perspective of what viability means, in the context of how yeast is used in brewing.
Give yourself 5 -10 mins to think about this and then click ‘Next’ to continue with this lesson.