Odd batch: Airlock pulling vacuum, large yeast cake but no krausen

[lobomute]

I brewed on Saturday (2/11) for the first time in years, and think that in my rush to wrap things up I made a doozie of a mistake...

I chilled the wort until it was around 120DegF at last reading and then transferred to my primary, then pitched... so it was less than 120 by the time I pitched... buuut it was likely greater than 80 or maybe even 90.. or 100.

I don't know exactly what the temp was when I pitched, but I had an "uh-oh" moment when I moved the carboy inside and it felt warm. I also didn't follow the recommended 3 hour activation time on my Wyeast 2112 smack pack... The pack was brought to ambient temperature in a StarSan bath, then it had maybe 30 minutes after the pack was smacked before it was pitched.

An hour or two later, I heard my airlock gurgle and I was thrilled... until I saw that it was gurgling in reverse. Somehow it was pulling a vacuum! Maybe as the wort continue to cool, the air above the wort contracted, and blah blah science blah.
https://youtu.be/q_aEbW84Igo

At 24 hours, the vacuum seemed to have stopped but there was no bubbling at all. The was also no krausen, but there was a very large yeast cake in the bottom! (see pictures) Is that normal?

I know the answer is "wait, be patient, time heals all beer" but I'm still worried... haven't seen a primary pull a vacuum, or a yeast cake that big without krausen or signs of expelling CO2.

Anything I should do besides wait and get more yeast and repitch?

View attachment IMG_6070.MOV

 

[Yooper]

The vacuum is because as the wort cools, it contracts and pulls a vacuum.

The yeast shouldn't have died at 120F, but it would be close. Even if some died off, it would not have killed all of them. I guess you're right that the answer is to be patient, and see what happens.

Try to keep it at 65 degrees or so, and see if fermentation does begin. It might, but there may be some flavor impacts.

 

[kh54s10]

Some of the yeast may have survived but certainly shocked. Get the temperature down to the mid sixties ASAP. The vacuum was caused by the hot wort continuing to cool.

If you can get the wort cooled before fermentation gets going you might not have too much off-flavor.

The smack pack is useable without smacking, the inner pack is just nutrient. It "wakes" up the yeast and gets them ready to ferment the beer. However you almost always should be making a starter when using most liquid yeasts. An average beer should have about 200 billion cells to start, Wyeast packs contain about 100 billion on packaging day.

If you can I would get another pack of yeast to pitch when the wort is in the mid sixties. Then control the temperature to keep it there. Fermentation will create heat.

 

[lobomute]

Can dead yeast cake like that? (picture above) Or is the fact that it can make that sort of formation a sign that it's alive and working?

 

[kh54s10]

Can dead yeast cake like that? (picture above) Or is the fact that it can make that sort of formation a sign that it's alive and working?

That is not a yeast cake, it is cold break, coagulated proteins etc.

 

[mongoose33]

Can dead yeast cake like that? (picture above) Or is the fact that it can make that sort of formation a sign that it's alive and working?

That is not a yeast cake, it is cold break, coagulated proteins etc.

When the yeast starts working that layer will "disappear" in that it will be mixed throughout the wort. Look closely with a flashlight when it's working; it'll look like a mini-storm going on in there, particles rising and falling.

When the krausen falls, all that stuff will pack into a thin layer maybe an inch or so thick.

You don't say how or if you aerated the wort; did you actively splash it when racking into the fermenter, did you shake a half-full fermenter to mix it w/ air, or oxygenate it? If you did none of those things, I'm thinking it will be very slow to go. Whatever yeast cells survived pitching will have low O2 with which to reproduce, which will slow things as well.

If it were me, and I could easily do it, I'd get another pack of 2112. If by the time I got home again there was still no activity, I'd smack it so it's activated, wait the requisite 3 hours, and pitch it. If there's activity when you get home with it, you can keep the new smack pack of 2112 in the refrigerator until the next brew.

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I brewed on Saturday using the White Labs equivalent of 2112; it's WL850. That yeast was past expiry by six weeks, but it's what I had so I made a starter with it, had it going from 8am Sat morning to pitching at 11:30am Sunday. I didn't cold crash it, I just pitched the whole thing into the fermenter.

I had bubbling (a little by 6pm), and this morning there's a healthy krausen going. I'm fermenting at 64 degrees, so it's slower than it might be at a higher temp.

In one sense my yeast was similar to yours in that it may not have had a full complement of viable yeast, and still it took off in 6 hours. Even if yours starts to go, I'm thinking it will be very slow, and if you didn't oxygenate, maybe really slow.

 

[lobomute]

You don't say how or if you aerated the wort; did you actively splash it when racking into the fermenter, did you shake a half-full fermenter to mix it w/ air, or oxygenate it? If you did none of those things, I'm thinking it will be very slow to go. Whatever yeast cells survived pitching will have low O2 with which to reproduce, which will slow things as well.

I actually used an oxygen tank attached to a fine bubbler stone that I drop into my primary fermenter between racking and pitching... gave it about a minute of oxygen - enough that the wort looked like it was boiling for that minute.