Have I killed my yeast?

How long should I wait till I repitch my yeast.

The senario is as follows:
Yesterday I put everything into my fermenter and then pitched the yeast. I new that the temp was a little high but fearing bacteria getting into the wort I pitched the yeast at 28 degrees C. As expected nothing much was happening last night. At 7:30 thismorning while the temp was still cool I got my first bubbles through my air lock. 16 - 18 hours after pitching the yeast. Today has gotten really hot (43 degrees) so I checked on my fermenter and realized that the temp was up to 30 degrees. Not wanting it to get any hotter I put my fermenter in a bath full of cold water and lowered the temp to 22 - 24 degrees. The problem is I haven't had any bubble since. How do I get it going again or had I already killed my yeast before I cooled it. How long should I leave it before I repitch some yeast at the lower temp?

That's hot, even for a distiller's yeast. I would re-pitch now. Extra yeast won't hurt the batch, dead yeast will.

Damn !!!!!! But thanks anyway

AAHHHHHHHHHHHHHHHHHH........... What the ???????

I repitched the yeast and gave it a stir...whoooshka!

Looks like I poured a bottle of detergent into a spa bath....

What now..... is it dead gone ..... I put the lid back on and refilled the Air lock... What do I do now?

Heeeeeelp

Blaine said:

AAHHHHHHHHHHHHHHHHHH........... What the ???????

I repitched the yeast and gave it a stir...whoooshka!

Looks like I poured a bottle of detergent into a spa bath....

What now..... is it dead gone ..... I put the lid back on and refilled the Air lock... What do I do now?

Heeeeeelp

Click to expand...

wait!! be patient and it will take off. Those suds were sign of fermentation. Dont do anymore stirring, you might aerate an already fermenting wort. Relax and let it go for about 24 to 48 hours and if nothing then make a starter and repitch.

Your original yeast was not dead, temperatures in the high 30s, low 40s WILL NOT KILL IT, just possibly cause it to develop some fruity esters that you may or may not like.

Adding the extra yeast did no harm but was more than likely unneccessary.

All yeasts have a certain 'lag time' from the time you pitch them to the time they actually get down to the serious business of fermenting. This period can vary between a few hours and a few days. The most dangerous part of this period is the overanxious brewer not allowing nature to take it's course and trying to fix something that's not broken.

You did the right thing by modulating the temperature of the fermenter, but as always, RAHAHB

Well, after repitching the yeast 4 days ago I have had very little bubble activity and everything seems to have stopped now. So without wanting to re-ignite the rather heated recent debate on the pros and cons of the hydrometer, I am planning on taking a reading tonight with a view to bottling on friday night.

Quick question though. When taking a reading from my primary fermenter should I open the lid and submerge my sterilized test tube in the wort or should I fill my test tube from the extraction tap?

Just wondering if the unsettled yeast cake on the bottom of my fermenter could give a false reading ?

Pull the bung on the air lock to get a sample from the middle. I use a turkey baster.

I think you probably temperature-shocked the yeast by cooling/heating too fast, making it go dormant for a day or so.

I would agree with casebrew. But with a few other thoughts. You may have fermented at high enough temperatures for long enough that your beer is actually done fermenting. High temperatures less than (I don't know celcius too well) 95F degrees for brief periods won't kill your yeast. But it might shock them. Also, if they don't get high enough to go into shock they might just go crazy for a while, finishing your ferment, in a sense. However, these high temps can cause off flavors. Either way your beer won't suffer too much. Off flavors from yeasts going into high temperatures are called esters (possibly esthers), and contribute flavors that are desirable in some ales.