Lesson 4 - Fermentation and Beer Flavour
Yeast and fermentation have an enormous impact on beer flavour. The most obvious changes during fermentation are sugar utilisation and the resultant formation of alcohol and carbonation. This is only a part of the story. Many thousands of compounds disappear and similar numbers of new ones are formed in fermentation as a result of yeast growth. This lesson describes what these are, how and why they are formed, and what effect they have.
Lesson Information
Pre-requisite Knowledge:
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Yeast Biochemistry (Yeast/Lesson 4)
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Fermentation Principles (Fermentation/Lesson 2)
Learning Outcomes:
By the end of this lesson you should be able to:
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Summarise the contribution that yeast makes to beer flavour.
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Describe the effect of yeast strains and other transforming organisms on beer flavour.
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List the major groups of yeast metabolites that contribute to beer flavour, describe their impact on flavour, and give typical flavour-threshold concentrations.
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Illustrate the metabolic pathways that lead to the formation of major yeast-derived beer flavour compounds.
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Describe ways to manipulate fermentation conditions to achieve the desired yeast-derived beer flavour compounds.
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Describe how mixed populations of non-standard brewing yeast strains and bacteria affect beer flavour.
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Demonstrate a knowledge of the metabolic pathways used by non-standard brewing yeast and bacteria which lead to the formation of beer flavour compounds.