I accidentally forgot to put a Wyeast French Saison (3711) yeast smack pack back into the fridge and it sat out in the garage for a few days. Anyone know the viability of it store at ~75F for a couple of days? I went ahead and broke the nutrient pack to see if it swells.
UPDATE
About an hour after breaking the nutrient pack, it seems to be slowly swelling. As planned, I will still try to make a 30 hour 1.5L starter.
How fresh is it? A fresh pack at room temp for a couple days might still be better than one kept cold for several months. I’d say continue as planned, especially if that plan is a starter.
My vote is its ok. Optimal? No, but it. Should work fine.
Good to hear it at least has a chance. Since my last post, the pack swelled up but it hasn’t ballooned out as much as it usually is. The mfg date is July 02.
With this particular situation, what size starter would you all recommend for this French Saison yeast?
Depends on the og of your beer, but I’d go big. 2 liter stepped to a 4 maybe? Use an online yeast calculator. Loading...
A couple of days at 75F is not going to hurt the culture. You should experience little to no difference in performance. Now, a couple of days at 100F is an entirely different story.
Freshness will. That is an old pitch.
Two and half months is not that old in the grand scheme of things. I have started yeast off of refrigerated slants that were two years old.
At 50% viability, the average Wyeast Activator pack has 50 billion viable yeast cells. The maximum cell density for a liquid culture is 200 million yeast cells per milliliter, which means that the maximum cell density for a 1L culture is 200 billion yeast cells.
The biggest mistake that amateur brewers make when making a starter is treating it like a small batch of beer. The goal of a starter is to increase yeast biomass, not produce ethanol. If possible, we want to pitch the culture just as the deceleration phase meets the stationary phase. That’s the point where no additional biomass growth occurs. From that point forward, reproduction only occurs in response to cell death and cell health begins to decline.
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Ideally, a 1L yeast culture should be pitched 12 to 18 hours after inoculation in order to ensure peak cell health. Yeast cells divide every ninety minutes after exiting the lag phase. Assuming 50% viability, the cells from a Wyeast smack pack only need to divide twice in order to reach maximum cell density under perfect conditions. However, under real-world conditions, we have to factor cell death and less than optimal growth conditions.
I like to get mine in the 30 day range. At 50% viability I’m more inclined to buy a second pack vs growing it up for 10 gallons. Time + DME is worth the $7.
1 liter stirred would get to an acceptable level for a 5 gallon saison. Otherwise it would take much larger lazy starter according to chris white’s numbers.
I’m in the fence about Kai’s numbers. Not that I don’t trust his numbers, it’s just that I trust white’s more. Kai has done some incredible work in Homebrew research.
The difference in propagation time between a 1L starter and a 2L starter is 90 minutes.
Initial count = 50 billion
Cell count 90 minutes after the end of the lag phase is 2 x 50 billion = 100 billion
Cell count 180 minutes after the end of the lag phase is 4 x 50 billion = 200 billion
Call count 270 minutes after the end of the lag phase is 8 x 50 = 400 billion (2L starter maximum cell density)
Call count 360 minutes after the end of the lag phase is 16 x 50 = 800 billion (4L starter maximum cell density)
The growth phase is called the “log phase” because the cell count grows exponentially as power of two every 90 minutes. Effectively, the cell count after the lag phase is complete is equal to:
initial_cell_count x 2^(integer(minutes_into_log_the_phase / 90)), where the symbol “^” denotes raised to the power of
IMO yeast are more resilient than we give them credit for.
3711 is a beast. I’m sure it will be fine.
Yeah, my first thought was “75F is nothing for 3711”. Should be just fine.
What is this, a culture for ants?!
Seriously though, I’m confused. I’ve harvested slurries that were >3 billion/mL.
I feel so much better knowing that math is hard at work here. I went ahead and made a 2L starter but hearing that pitching too much yeast is hard - but not impossible - to do, I bought a second smack pack to pitch straight in on top of the starter.
And it smelled great coming out of the pack before I threw it in the starter. Can’t wait.
I’m assuming - and we know what that does - that 200cells/mL is the max growth you can get out of the total volume of a starter. Of course if you let it settle the dense cells at the bottom will be much more dense, but they didn’t grow at that density.