Author Topic: Unrefrigerated Wyeast Pack  (Read 2100 times)

Offline tress

  • Cellarman
  • **
  • Posts: 50
  • Drink Great Beer
    • View Profile
Unrefrigerated Wyeast Pack
« on: September 20, 2014, 01:40:26 AM »
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.
"Beer. Now there's a temporary solution." - Dan Castellaneta

Offline tress

  • Cellarman
  • **
  • Posts: 50
  • Drink Great Beer
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #1 on: September 20, 2014, 01:42:16 AM »
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.
"Beer. Now there's a temporary solution." - Dan Castellaneta

Offline Jimmy K

  • Official Poobah of No Life.
  • *
  • Posts: 3646
  • Delaware
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #2 on: September 20, 2014, 01:56:07 AM »
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.
Delmarva United Homebrewers - President by inverse coup - former president ousted himself.
AHA Member since 2006
BJCP Certified: B0958

Offline klickitat jim

  • I must live here
  • **********
  • Posts: 8604
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #3 on: September 20, 2014, 03:13:41 AM »
My vote is its ok. Optimal? No, but it. Should work fine.

Offline tress

  • Cellarman
  • **
  • Posts: 50
  • Drink Great Beer
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #4 on: September 20, 2014, 08:54:27 AM »
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?
"Beer. Now there's a temporary solution." - Dan Castellaneta

Offline Stevie

  • Official Poobah of No Life.
  • *
  • Posts: 6858
    • View Profile
Unrefrigerated Wyeast Pack
« Reply #5 on: September 20, 2014, 01:51:57 PM »
Depends on the og of your beer, but I'd go big. 2 liter stepped to a 4 maybe? Use an online yeast calculator. http://www.yeastcalc.co/homebrew-calculators
« Last Edit: September 20, 2014, 01:54:27 PM by Steve in TX »

S. cerevisiae

  • Guest
Re: Unrefrigerated Wyeast Pack
« Reply #6 on: September 20, 2014, 04:09:13 PM »
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.


Offline Stevie

  • Official Poobah of No Life.
  • *
  • Posts: 6858
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #7 on: September 20, 2014, 04:59:04 PM »
Freshness will. That is an old pitch.

S. cerevisiae

  • Guest
Re: Unrefrigerated Wyeast Pack
« Reply #8 on: September 20, 2014, 06:46:52 PM »
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.

[/URL]

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.



Offline Stevie

  • Official Poobah of No Life.
  • *
  • Posts: 6858
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #9 on: September 20, 2014, 09:22:23 PM »
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.

S. cerevisiae

  • Guest
Re: Unrefrigerated Wyeast Pack
« Reply #10 on: September 21, 2014, 12:35:42 AM »
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 


Offline Joe Sr.

  • Official Poobah of No Life.
  • *
  • Posts: 4383
  • Chicago - NORTH SIDE
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #11 on: September 21, 2014, 02:37:01 AM »
IMO yeast are more resilient than we give them credit for.

3711 is a beast.  I'm sure it will be fine.

It's all in the reflexes. - Jack Burton

Offline erockrph

  • Official Poobah of No Life.
  • *
  • Posts: 6229
  • Chepachet, RI
    • View Profile
    • The Hop WHisperer
Re: Unrefrigerated Wyeast Pack
« Reply #12 on: September 21, 2014, 03:15:35 AM »
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.
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer

Offline a10t2

  • Official Poobah of No Life.
  • *
  • Posts: 4505
  • Ask me why I don't like Chico!
    • View Profile
    • SeanTerrill.com
Re: Unrefrigerated Wyeast Pack
« Reply #13 on: September 21, 2014, 03:04:30 PM »
The maximum cell density for a liquid culture is 200 million yeast cells per milliliter

What is this, a culture for ants?!

Seriously though, I'm confused. I've harvested slurries that were >3 billion/mL.
Sent from my Microsoft Bob

Beer is like porn. You can buy it, but it's more fun to make your own.
Refractometer Calculator | Batch Sparging Calculator | Two Mile Brewing Co.

Offline tress

  • Cellarman
  • **
  • Posts: 50
  • Drink Great Beer
    • View Profile
Re: Unrefrigerated Wyeast Pack
« Reply #14 on: September 21, 2014, 04:25:19 PM »
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.

3711 is a beast.  I'm sure it will be fine.

And it smelled great coming out of the pack before I threw it in the starter.  Can't wait.

"Beer. Now there's a temporary solution." - Dan Castellaneta