Lesson 8 - Fermentation Unit Final SAQ
You have now completed the Fermentation unit. This lesson provides the opportunity to test your knowledge with a last set of self-assessment questions.
Suggested Response - Q1
**Your brewery has a tank farm of 30 cylindroconical fermenters, each with an operating volume of 5,000 hL. You produce one beer quality, with a fermentation cycle time of 10 days. The fermenters require 12 hours to fill and a further 36 hours to cool, empty, and clean. The wort gravity is brewed at sales gravity of 12 °P.
a) What is the theoretical maximum volume of beer that the tank farm can produce per annum?
b) If high gravity brewing were introduced using a wort of 18 °P, with the result that the fermentation cycle time increased to 14 days, how would the theoretical capacity change?
Response:
a) Sales gravity fermentation cycle times are (10 + 0.5 + 1.5) = 12 days including time to fill, empty, and clean.
Therefore, the number of cycles per annum per fv = 365/12 = 30.4
Therefore, based on 30.4 cycles for 30 fvs, each with a capacity of 5,000 hL, the theoretical output from the tank farm is:
(5,000 x 30 x 30.4) = 4,560,000 hL per annum.
b) Increasing the gravity increases the cycle time to (14 + 0.5 + 1.5) = 16 days.
Therefore, the number of cycles per annum decreases to 365/16 = 22.8
The annual output changes to (5,000 x 30 x 22.8) = 3,420,000 hL per annum.
However, after dilution from 18 °P to 12 °P, this increases to:
3,420,000 x 18/12 = 5,130,000 hL per annum.