Document code
Document title
Purpose
Responsible officer
FY 008
Version no.
Pitching rate estimation strategies
Assess the effects of yeast inoculation variables and growth
conditions on green beer properties
Brian Baxterhill
Date commenced
Date filed
Trial summary
Process
Cooled, aerated
wort is
inoculated with
yeast to ferment
into green beer.
Variables
Yeast quality
and quantity,
temperature,
nutrient
balance, time.
Performance
criteria
Strategies
Prior
knowledge
Yeast cycle
progression,
% alcohol,
fermentation
by-products.
Each wort batch requires the
correct amount of yeast and
process conditions to ensure
optimum production of green
beer.
–
Trial parameters and outcomes
Reporting details
Laboratory trials are still at the incomplete stage. Substantial data
for Australian yeast viability and plant performance under a range of
conditions has been collected. This has lead to reliable measures
of pitching rates for wort with ranges of nutrient balances. Some
troubleshooting of plant performance has been successful, due to
specific knowledge of local factors which alter yeast cycle phases in
the plant. The late release of African yeast from AQIS has delayed
tests on its viability and optimum growth and output conditions. Also
management uncertainty about parallel fermentation (each yeast
used to ferment a separate wort batch, with the matured beers to
be blended at the packaging stage) or mixed fermentation (both
yeasts present in the same batch of wort) processes has caused
delay.
Final details will appear in
report FY008-1.
Copies to be forwarded to:
Substantial laboratory work is still needed to determine qualitative
and quantitative data on a number of fermentation by – products.
Undoubtedly the African yeast will lead to a few surprises.
Report status
(insert date under the latest
appropriate term)
IN PROGRESS
Date:
AWAITING ADDITIONAL
AUTHORISATION
Date:
COMPLETE
Date: