Does harvested slurry behave differently than original?

[North_of_60]

Whenever I have used a packet of Nottingham yeast, including the one I harvested from, it takes about 6 to 8 hours till I’m seeing airlock activity. It picks up speed till the airlock is a constant bubbling and continues for two and a half days then slows till it stops by the end of day three. After that the airlock stops burping.

The slurry I pitched took off in less than 3 hours and after 12 hours it was going steady, however, a little less vigorously than the original. It continued for about the same amount of time as the original, two and a half days. Then instead of slowing to a stop it slowed to a consistent burp every 1 and a half minutes or so. It kept that up for 48 hours. Now it is 2 to 3 minutes between burps.

The slurry was stored at 34 degrees for a month before using.

The fermentation temperature has been held at 68 degrees. I usually shoot for 66 but this one got a bit warmer.

Does harvested yeast behave differently than the original?

Or, did I under pitch?

This is a chocolate porter, there is 3 oz of 100% Cocoa powder that was added at 15 minutes before the end of boil. Would this have any affect on fermentation?

Picture of what I pitched: Edit: I pitched 1 jar just like the ones shown below.

 

[Northern_Brewer]

Does harvested yeast behave differently than the original?

Yes - even if you start with liquid yeast, there are definite generational effects - the brewers of Heady Topper claim to be able to identify what generation of Conan it's been made with just by the taste of the finished beer. But the step from dry yeast is bigger, because it's like the yeast has to "unpack" its belongings before it can set to work. So it's quite normal for a dry yeast to take longer to get going than a wet one.

But there's a separate effect, that Nottingham - like it seems many dry yeast - appears to be a blend of an ale yeast similar to WLP039 and a "lager" yeast of some kind. The mix of strains will drift at each generation, and after a few generations the new mix behaves very differently to the original mix.

 

[homebrewer_99]

In my mind, "harvested yeast" equates to "washed" (collected and stored in the fridge), while "slurry" implies straight from the bottom of a primary.

The slurry would not be "clean" (as opposed to washed), but would still be sprinting (active) when used directly from the primary.

Washed yeast would need to go through a new life cycle.

 

[bucketnative]

I have found that with Belle Saison slurries, the second or third generation typically gives a more complex flavor from the yeast than does the first use out of the package. This has been consistent now for a three years. I usually try to get about three passes out of the yeast before I get sick of storing it (or I have built up enough beer), and wash it down the drain after that.