Lesson 8 - Hygiene End of Unit SAQ
This lesson allows you to test yourself on the material covered in the Hygiene unit, and determine the level to which you have attained the unit’s outcomes.
Self-Assessment Questions
1. *** Due to poor planning, a standard lager brew with 15 IBU was cooled and aerated into a fermenter that was only rinsed before filling. The next yeast will only be available in 48 hours’ time. The previous brew in the vessel was a Weiss beer.
Discuss the types of microorganisms that could contaminate the wort and describe the ways in which they could affect the finished beer.
2. *** Your brewery is experiencing positive results on early fermentation samples from a WLN agar medium. You wish to identify the potential contaminants as quickly as possible.
Discuss both the methodology and applicability of rapid biochemical or molecular tests that will identify the contaminants.
3. *** Your brewery has 30 fermenters and is using a manual fermenter CIP system with which to clean them. You have been tasked to investigate a new system for your current capacity that will be able to accommodate future expansion.
a. With the help of diagrams, describe which system you would recommend, including its operation and automation.
b. After a week of operation, stock counts are showing a higher caustic use than the manual system! How do you investigate this and ensure that you reduce caustic moving forward?
4. *** Your brewery has just experienced a bad quality month. You have received microbiological trade complaints relating to three different batches. The complaints were related to beer that displayed the following characteristics:
Complaint 1 - A bottled lager, exhibiting turbidity and ropiness, with a strong butter aroma and sour taste.
Complaint 2 – A bottled ale, exhibiting turbidity and giving an unpleasant sulphuric and vegetal/parsnip aroma.
Complaint 3 – A traditional, barrel-aged strong ale with a sour taste and vinegary aroma.
Explain the likely cause of each contaminant and describe from where in the brewing process the contaminations could have originated. In addition, describe how these contaminants exploit the brewing conditions in order to grow and spoil the beer.
5. ** Discuss the microorganisms that contaminate the raw materials used for brewing; describe the various threats they pose to both the brewer and consumer.