How resilient is yeast

Got my ingredients from Austin Homebrew via UPS yesterday afternoon. Got everything unpacked and found my yeast (Wyeast Kolsch "Smack Pack")right next to what was labeled "Ice Pack." However, if that had once been ice, it no longer was. It was all warm. First thing I did was put it in the fridge. I will know before I pitch it if it is still viable because of the Smack Pack but what are the chances I will have to head out to my LHBS tomorrow morning?

Just get a starter going today. Then, you'll know for sure if you have viable yeast or not. For the most part, I would really worry about it too much, but I would still for sure make a starter. Even on my brews where I "know" the yeast is good, I still make a starter. Starters aren't only good for proofing yeast, but they also help get the cell count up high enough for a direct pitch into your wort. Technically, the SmackPacks you get from Wyeast do not contain the proper amount of yeast cells for pitching...

I was under the impression that the Smack Packs were their own starter and that breaking the nutrient pouch in the bag got you up to the proper amount of cells. Was this wrong?

Neumann:

Under ideal conditions, an Activator smack-pack will contain around 100X10E9 (100 billion) yeast cells after it's smacked and swelled. Depending on who you ask, that's either just enough to inoculate 5 gallons of 1.060 wort (that's what Wyeast says), or about half of the optimum pitching rate (208 X10E9 cells, per Jamil Z's calculator).

Many people have fine results with just pitching an activated smack-pack. However, many other people find that building starters with liquid cultures makes for better beer -- I'm firmly in that camp.

Given that your smack pack may have been stressed by overheating, it seems to me that building a simple 1 quart starter to ensure healthy yeast would be a good idea. In my experience, brewing great beer really comes down to a few simple things: good ingredients, good yeast management, and good temperature control.

I totally agree with jds and was just like you at one point and didn't even know what a starter was when I was a extract brewer.

The point is that if you are unsure it would be wise to do a starter. A starter doesn't mean you have to have a stir play or a fancy flask. You can use a growler or any semi-large, maybe half-gallon glass jar of some sort.

Here is some ghetto inspiration for you

Your yeast will most likely not be hurt by that heat.

I had mine shipped from Atlanta through the hottest parts of the country with no ill effects and no ice pack.

There was a White Labs guy in another thread that mentioned they took unrefrigerated yeast and shipped it back and forth from coast to coast a couple of times in the middle of summer, and when they popped it open it was still highly viable.

Well I hit the smack pack yesterday at lunch and by 6 there was barely any swelling of the package. I went ahead and made up a starter but after 18 hours I'm not seeing any activity. Is this normal? I assumed I'd see pretty moderate fermenting by now, but nothing... I went to my LHBS and picked up some dry yeast just in case. I'm doing this brew tomorrow, one way or the other.

Many times you will not see alot of activity in a starter. I have only had a couple of starters have a decent krauesen, however, most don't do much at all. If you are without a stirplate, just swirl your container as often as possible to promote gas transfer between co2 and o2. You can hear the co2 come out of solution when you swirl, and if you get that nice yeastie smell also, your starter is growing fine.

As for the OP question, yeast is very resilient!

Okay, I feel a little bit better. I had been being very careful with it but I went and swirled it a bit and definitely heard the fizz of CO2 being released. It also appears to have a layer of yeast at the bottom. Here, have a look:


That look viable to you guys?

Looks good, and that "fiz" is a great sign that the yeast are doing their "aerobics" and multiplying, just swirl as often as possible, it will make a big difference in the yeasts growth.

Yes, try to swirl at least every hour for the first however many that you can...