Lesson 3 - Wort Boiling Theory SAQ

1.     *Indicate whether the following statements are true or false. If false, please give the correct answer.

a)    Enzymes are denatured below boiling temperatures.

b)    Boiling destroys all microorganisms in wort.

c)    It is best to achieve the evaporation of at least 15% of the wort volume during the boil to ensure that all the necessary changes occur.

d)    Reactions involving amino acids and reducing sugars are the only source of flavour during the boil.

e)    DMS can form after wort boiling is complete.

2.       *Give short answers to the following:

a)    What is the optimum pH at the end of wort boiling? Why is ensuring that the pH is correct during the boil important?

b)    Your start of boil gravity is 9.7°P and end of boil gravity is 10.6°P, what is your percentage evaporation? Do you think this is acceptable? Why?

c)    When do kettle finings need to be optimised and what two parameters do we need to balance when optimising them?

d)    How can you improve the utilisation of T90 hops during wort boiling?

e)    The wort DMS at the end of wort boiling is 220 μg/L. How is this likely to affect the beer, and what action would you take for future brews?

3.       **/*How can you control a boil to optimise flavour stability?

4.       **What raw materials and process aids do we typically add during wort boiling; what role do they play in wort and beer quality?

5.       ***You have been asked to reduce the evaporation during the boil from 8% to 4% on a trial brew. What do you need to check after the trial brew before you can conclude that this reduction has not affected quality? And how will you check it?