Document code / FY 008 / Version no.
Document title / Pitching rate estimation strategies
Purpose / Assess the effects of yeast inoculation variables and growth conditions on green beer properties
Responsible officer / Brian Baxterhill
Date commenced
Date filed

Trial summary

Process / Variables / Performance criteria / Strategies / Prior knowledge
Cooled, aerated wort is inoculated with yeast to ferment into green beer. / Yeast quality and quantity, temperature, nutrient balance, time. / 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

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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.
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. / Final details will appear in report FY008-1.
Copies to be forwarded to:

Report status

(insert date under the latest appropriate term) / IN PROGRESS
Date: / AWAITING ADDITIONAL AUTHORISATION
Date: / COMPLETE
Date: