Starter size for pressure-fermented lager at room temp?

[luckybeagle]

Is an extra big starter necessary for fermenting a lager at room temp if using a pressure fermenter (Fermzilla, 10-15psi)? Or can I get away with a standard ale pitch since it'll be fermented at about 69F, and pressure fermentation reduces esters anyway?

 

[Vale71]

Increased pitch rate is part of the warm lager pressure fermentation process. The idea is to inhibit yeast growth as much as possible to counteract the effects of a higher temperature. This means the pitch rate should be even higher than what it should be if the same batch were fermented cold using the same yeast.

 

[luckybeagle]

Increased pitch rate is part of the warm lager pressure fermentation process. The idea is to inhibit yeast growth as much as possible to counteract the effects of a higher temperature. This means the pitch rate should be even higher than what it should be if the same batch were fermented cold using the same yeast.

Thanks! This makes sense. I had a long drive today so I listened to Beersmith Podcast #163 - Pressure Fermentation with Chris White and John Blichmann. It was pretty informative.

In their 20 gallon test batch of a lager, they did 5 gallons at lager temps, 5 at room temp under x pressure, 5 at y pressure, and 5 at z pressure. They pitched the same lager pitch rate in each one to keep the variables as similar across batches as possible. It sounds like they had good results with their 15psi batch (~1 bar) and fewer in their 2 bar batch, but what you're saying makes sense since the goal with a warm temp, pressurized lager fermentation is to suppress those esters, which can be byproducts of temperature and yeast stress.

My logic was incorrect--I was really hoping a standard ale pitch would've cut the mustard under the rationale that the temperature is higher at room temp than lager fermentation temps.

I am excited to experiment with higher gravity ales to see if there's a pressure I can ferment at without temperature control. For example: a Belgian Golden Strong -- I ferment my house recipe for that one at 62F followed by a 1F increase per day. I'm after minimal esters and fusels, with some nice spice and pepper phenols. Chris White said fusels are minimized under a pressure fermentation, just like fruity esters. I wonder if setting the spunding valve on my Fermzilla to 5 or 10psi would allow me to ferment that same beer at 70F whilst keeping esters low... I might have to brew up a couple SMaSH BGSs to find out. I'd likely pitch a 1.25MM / mL/ ºP. What are your thoughts on that?