To start fermentation at 48 to 55°F (8–12°C), begin with more yeast. Reference the Custom Culture Calculator in the White Labs app for accurate pitch rate amount.
Cool wort to hybrid/ale temperatures (60-65°F/15-18°C), pitch yeast and maintain temperatures until signs of fermentation are evident, CO2 formation or pH decrease. Begin to lower fermentation temperatures until desired lager temperatures are reached. In order to maintain vitality, it’s recommended to lower lager fermentation temperatures (0.5-1°C) per hour.
Use a yeast step up. Grow in 10 percent of your fermentors final volume (i.e. for a 20BBL propagate in 2BBL of wort), pitch step up volume 0.5L of yeast per 1BBL. Maintain propagation at the same temperature you are going to pitch your yeast. After 24 to 48 hours, add propagation to fermentor. After the initial pitch, it’s recommended to use higher pitching rates. Collect two to three times the normal slurry. Perform a cell count, viability analysis and a microbial stability test on the slurry to determine pitch rate from 1.2 to 2 million cells per milliliter of wort per degree Plato.