1-Step-10-Fold Propagation
A 1-Step-10-Fold propagation is the most common type of propagation used by brewers. This is a single step propagation which involves inoculating a small volume of wort, allowing it to attenuate 50-75%, and then adding a 10 fold volume of oxygenated wort on top.
Volume:
Determine the volume of propagation wort by dividing the final desired fermentation volume by 10. Next subtract this volume from the final desired fermentation volume to determine the amount of wort needed for the final fermentation.
Example: A 20 Bbl final fermentation volume will require a 2 Bbl propagation. Following gravity drop, an addition of 18 Bbl of wort will be required for this fermentation.
Pitch Rates:
The following are typical pitch rates for a 1-Step-10-Fold propagation:
Ales: 1 liter per Barrel or Hectoliter
Wheats: 1 liter per Barrel or Hectoliter
Lagers: 2 liters per Barrel or Hectoliter
High Gravity: 2 liters per Barrel or Hectoliter
Propagation Example (1-Step-10-Fold):
A 20 Barrel brewery wants to propagate yeast for a 1.060 gravity beer.
The brewery would order 2 liters of yeast and inoculate 2 barrel of well oxygenated wort at 70°F.
The propagation would be allowed to ferment for 48 hours or until 50-75% gravity drop.
Following gravity drop, 18 Bbl of wort would be run in on top of it.
The initial cell count in this example would be around 10-12 million cells per ml. If the yeast is allowed to ferment for 48 hours, the cell count would increase enough to supply 5-6 million cells per milliliter when increased to a total of 20 barrels.
