[Drewch]

I've read a lot of different takes around the internet on how Lallemand Philly Sour responds to different pitching rates.  There seems to be consensus that under- or over-pitching will result in lower lactic acid production, but I haven't found a definitive answer on what the Goldilocks zone is.

Lallemand's pitch rate calculator says 0.50 gram/liter for 1.030 wort, but AFAICT it recommends that for all of their dry yeasts.

Does anyone have experience with getting optimal lactic production from this yeast?

[kramerog]

I have brewed with it to make 3 gallons of sour beer. My recollection is that 1 packet provides higher acidity up to 3 gallons, which is why my batch size was 3 gallons. At 1 packet per 5 gallons you get lower acidity. I have not seen anything to indicate that overpitching creates less acidity.

[Drewch]

I followed their pitch rate calculator and did 2g in 4L, and it's a bit lacking in acidity. I'll try another batch and go higher; maybe 1 g/l instead of 0.5 g/l. That would just about match your one pack into 3 gallons (11 g into 11.3 l).

[clibit]

In depth Philly feedback and graphs here...

http://suigenerisbrewing.com/index.php/2021/02/12/diving-deep-in-to-philly-sour/

He measured pH in brews with different pitch rates which indicated pH finished lower if you pitch in the range 0.5 to 1 billion cells per ml. I haven't worked out what that means in grams per litre or anything yet.

He also covers the effects of oxygen and glucose.

I'm yet to use my first packet of Philly which is getting a bit fed up in my fridge.

[Drewch]

Lallemand lists the viability as "≥ 1 x 10⁹ CFU per gram of dry yeast".  That's 1 Billion CFUs per gram -- is there a translation between CFUs and cell count?  Assuming each CFU is only one cell, then:

(10⁶ cell / ml) x (4000 ml) x (1 g / 10⁹ cell) = 4 g for a 4L batch... which is about double what I pitched.  I can also try adding more simple sugars next time.