Danger of overpitching saved yeast?

[Bobcatbrewing42]

I'm usually a yeast saver. I live far from a brew shop. I use mostly dry yeasts. I've been advised by Grandmasters that saved yeast is good for about a month in the fridge. In my experience, month old yeast can be very viable or mostly dead. I just split a batch of red beer into a Marzen and a mongrel sort-of Irish Red ale. I pitched about a pint of slurry from a two month old S-23 lager and a one month Bry97. Both started within a couple of hours at 53 degrees and 66 deg and went out the blowoff tubes overnight. That's unusual. Questions- Am I overpitched?(day three both a steady ferment). How do you know if you are overpitching saved yeast? Does lager yeast save longer than ale yeast?

 

[brewbama]

Per WYeast:

REPITCHING BY WEIGHT OR VOLUME:

Estimates of cell counts can be made using percent yeast solids of the slurry. Percentage of yeast solids per volume of slurry can be estimated by allowing a sample to sediment under refrigeration and estimating the percent solids. Generally 40-60% yeast solids will correlate to 1.2 billion cells per mL. This will vary with the yeast strain. By using this method with every brew, a brewer can achieve consistent pitch rates batch to batch resulting in a more consistent product.

Once the brewer has determined the desired pitch rate and cell density of the slurry the brewer can collect the appropriate quantity of yeast. Slurry can be harvested based on volume or weight. 1.0 L (1 quart) of yeast slurry (40% yeast solids) weighs approximately 1.1 Kg (2.4 lbs). The following guidelines will deliver the appropriate pitch rates.

Ales with a specific gravity < 1.064 (16 °P): pitch 1.0 Kg (2.2 lbs) of thick slurry (40% yeast solids) per 1 BBL (1.17 hL) or 1 Liter (1 quart) of thick slurry per 1 BBL (1.17 hL)

Lagers with a specific gravity < 1.064 (16 °P): pitch 2.0 Kg (4.4 lbs.) of thick slurry (40% yeast solids) per 1 BBL (1.17 hL) or 2 Liters (2 quarts) of thick slurry per 1 BBL (1.17 hL)

High lagers with a specific gravity > 1.064 (16 °P): pitch 3.0 Kg (6.6 lbs.) of thick slurry (40% yeast solids) per 1 BBL (1.17 hL) or 3 Liters (3 quarts) of thick slurry per 1 BBL (1.17 hL)

Ref: Professional | Yeast Harvesting & Repitching - Wyeast Lab

I believe 1 US BBL ≈ 31 US gal. 1 US Qt ≈ 32 US fl oz. So, ~ 1 fl oz per gal Ale harvested yeast slurry and 2 fl oz per gal Lager harvested yeast slurry < 1.064. ~3 fl oz per gal harvested yeast slurry > 1.064.