I’m planning on a 1.048 German Pils using W-34/70 for the first time. Yeast packs dated 01-2016 so production date 01-2014 and 69% viable. BeerSmith says I need 353 billion cells and (2) packs of yeast yielding 276 billion, a bit of an under pitch as calculated by BeerSmith. Mr. Malty indicates using 2.50 packs yielding approximately 345 billion cells. The cost of the third pack is not an issue, just want to make the best beer.
So my question is, pitch 2 packs at 276 billion, or 3 packs at 414 billion?
I have not decided on the mach schedule yet, may just do a single infusion but the Recipe Specifics:
Recipe: German Pils
Brewer: Ron
Asst Brewer:
Style: German Pilsner (Pils)
TYPE: All Grain
Taste: (30.0)
Recipe Specifications
Boil Size: 7.98 gal
Post Boil Volume: 5.98 gal
Batch Size (fermenter): 5.25 gal
Bottling Volume: 5.25 gal
Estimated OG: 1.0479 SG
Estimated Color: 3.0 SRM
Estimated IBU: 38.3 IBUs
Brewhouse Efficiency: 75.00 %
Est Mash Efficiency: 82.1 %
Boil Time: 60 Minutes
Ingredients:
Amt Name Type # %/IBU
9.00 lb Best Malz Pilsen Malt (2 Row) German Pil Grain 1 100.0 %
2.00 oz Hallertauer [3.10 %] - Boil 60.0 min Hop 2 23.5 IBUs
1.00 oz Hallertauer [3.10 %] - Boil 30.0 min Hop 3 9.0 IBUs
1.00 oz Hallertauer [3.10 %] - Boil 15.0 min Hop 4 5.8 IBUs
1.00 Items Immersion Chiller/Pump (Boil 15.0 mins) Other 5 -
0.50 tsp Yeast Nutrient (Boil 10.0 mins) Other 6 -
0.50 Items Whirlfloc Tablet (Boil 5.0 mins) Fining 7 -
1.00 oz Huell Melon [4.50 %] - Boil 0.0 min Hop 8 0.0 IBUs
2.0 pkg Saflager Lager (DCL/Fermentis #W-34/70) Yeast 9 -
Mash Schedule: Single Infusion, Medium Body, Batch Sparge
Total Grain Weight: 9.00 lb
Name Description Step Temperat Step Time
Mash In Add 14.00 qt of water at 154.9 F 145.0 F 45 min
Mash Out Add 8.00 qt of water at 189.3 F 160.0 F 45 min
Sparge: Batch sparge with 2 steps (Drain mash tun , 3.56gal) of 185.0 F water
I don’t think it’s ever a good idea to underpitch a lager (or any beer) in a significant way. But for a sub 1.050 lager, I’ve had good results (clean beer, good attenuation) rehydrating two packs. And I’ve seen several brewers here and elsewhere who reported good results doing the same. Worst case you could always hit it exactly and pitch the extra half pack.
Yeast cultures are kind of like nuclear weapons in that being close to the target is more than adequate to get the the job done. The difference between 276 billion cells and 353 billion cells is not even a full replication cycle. The yeast biomass cell count grows roughly at a rate of 2n, where n is the number of minutes that have elapsed since the end of the lag phase divided by 90 at 25C. The replication period lengthens as fermentation temperature decreases.
Per the spec sheet:
“increase dosage for pitching below 12°C (53°F), up to 200 to 300 g/hl at 9°C (48°F)”
So if I’m doing the math correctly, for 5.25 gallons, say 20 liters, fermenting at 48-50 degrees, I should be pitching somewhere between 40 to 60 grams of yeast. Basically 3 to 5 11.5 gram packets. Understanding that pitching “exactly per spec” may not be required in real world home brewing applications. And while two packets may work just fine and people have had great success with that, pitching 3 or 4 packets to me may be cheap insurance.
Increase the pitch rate or the temp(personally I would do temp). 2 packs would be fine at 53ish(but not below). FWIW, YMMV, and all the other disclaimers.
You have to try pretty hard to over pitch a lager and I can guarantee you, you will never over pitch on the yeasts first fermentation. If your lager yeasts are not chewing though ~12 gravity points per day, you did not pitch enough yeast. For this beer in question, I would be at FG (1.010ish) 4 days from brewday.
But don’t make the mistake of racking it just because it hit terminal gravity in those 4 or 5 days! Let the yeast do some cleanup on a lager. See the Brulosopher lager schedule for the short turn lager technique. You can go grain to glass in 24 days. It really works.
You guys are missing the big picture. It does not make a darn bit of difference if one pitches 200 billion cells or 400 billions cells in a non-high gravity (i.e., non-hypertonic) solution, especially one that is fermented below the temperature at which most microflora give up the ghost. The maximum cell density for 1 liter is roughly 200 billion cells. A volume of 5.25 US gallons is approximately equal to 20 liters; therefore, the maximum cell density for 20 liters is 20 x 200 billion = 4 trillion cells. Unless one pitches 4 trillion cells, the fermentation is going to experience a period of exponential growth. What matters is dissolved O2 and the amount of carbon that is available to the yeast cells. Sugar is carbon bound to water; hence, the term carbohydrate (all of the sugars found in wort are multiples of CH2O). Yeast cells consume carbon. Given enough carbon and O2, one could fully attenuate a batch of wort by pitching just one yeast cell.
Relax… I had a 1.095 OG doppelbock, pitched with one pack of 34-70 (non-rehydrated), and scored a 42 in the first round of NHC. The wort was well O2ed, and the pitch rate was sufficient to yield a great beer.