Lag Time Vs Temp ?

[rich_lamb]

Hi guys,
does anybody have any empirical evidence of how much yeast lag time varies with pitching temp? I know; there's a pile of variables that will affect lag time, just an "all things being equal" question.

I am curious because in the past I've used an immersion chiller, and only chilled to about 22 deg, to save the precious water. When I pitch at 22 I put the fermenter under temperature control which takes about 24 hours to come down to 19-20. I aerate using the "thrashing spoon" method, and I find (for correct pitching rates) my yeast is kicking off in about 6 hours - and my active ferment is usually about 1-2 days. Seems to be independent of gravity and yeast strain for me.

My latest brew is my first no-chill, so I was able to pitch at a nice cool 18 deg. But there's only limited krausen after about 16 hours and bubbling is just beginning, and slowly.

Is the fermentation usually much more subdued when pitching this cool? The yeast I'm using is Nottingham.

 

[newguy]

In general, the cooler you pitch, the longer the lag time. Two things that can have an influence are the amount you pitch (more yeast pitched will still get going well at lower temps) and the oxygen you introduce (again, more O2, the cooler things will still work).

 

[SJW]

This is very interesting. I did a German Pilsner yesterday and pitched two packs of S-189 (hydrated) at 11pm last night and 15 hours later I still have 0 sign of fermentation activity. Normally with dry yeast I pitch at 20 deg C a cool to 10 deg C but this time I thought I would pitch cold, and I am not happy. If there is no sign of activity after 24 hours I could pitch a 3rd pack of S-189 or just pitch some saved slurry from a Wyeast 2124.

Steve

 

[rich_lamb]

Hmm, don't know much about lager yeasts - I'm always doing ales.
I have a bit of yeast left ready to go, but I'm holding back on using it unless its an emergency - I'd prefer to get a normal yeast "growth" phase if I can. Before I pitched more I might raise the temp a bit, but as I say it is *sortof* going...

I was interested to see if others have this experience?

 

[SJW]

This is very interesting. I did a German Pilsner yesterday and pitched two packs of S-189 (hydrated) at 11pm last night and 15 hours later I still have 0 sign of fermentation activity. Normally with dry yeast I pitch at 20 deg C a cool to 10 deg C but this time I thought I would pitch cold, and I am not happy. If there is no sign of activity after 24 hours I could pitch a 3rd pack of S-189 or just pitch some saved slurry from a Wyeast 2124.

Steve

I pitched a 3rd pack of S-189 last night. This is getting crazy. This is the first time that I have cooled the wort to 10 deg C for pitching and nothing. So I pitched a 3rd pack last night and I have some foam lace on the top now so its away. But from now on, if I use dry yeast again, I will be doing what I used to do and pitch at 20 deg C and cool over night.
I suspect what I did was thermal shock the yeast. I rehydrated with tap water and it would of been about 20 deg C and then dumped it into a 10 deg C wort.

Steve

 

[raven19]

+1 for plenty of oxygen.
Is the gravity dropping?

 

[Ross]

I pitched a 3rd pack of S-189 last night. This is getting crazy. This is the first time that I have cooled the wort to 10 deg C for pitching and nothing. So I pitched a 3rd pack last night and I have some foam lace on the top now so its away. But from now on, if I use dry yeast again, I will be doing what I used to do and pitch at 20 deg C and cool over night.
I suspect what I did was thermal shock the yeast. I rehydrated with tap water and it would of been about 20 deg C and then dumped it into a 10 deg C wort.

Steve

Steve,

I wouldn't have used a 3rd pack, patience was all you needed....your 1st 2 packs are what are showing this morning.
Yes, thermally shocking the yeast like that was not a good idea. If you rehydrate in warm water, you should slowly drop the temp by additions of some cooled wort or put in the fridge to drop, not tip into a full batch as you did. If your sanitation is up to scratch though all will be fine.

cheers Ross

 

[seemax]

+1

2 things, yeast will take its time at 10C and temp shock will delay things a lot. I recently pitched 15g of S-189 into a 15L of wort no chilled to 10C (I also normally pitch at 20C and then cool). Nothing for 2 days, then 3rd day only very slight signs of krausen. 2 weeks later and it's fully fermented as expected and tastes good, no signs of infection.

 

[SJW]

I guess I am just used to Liquid yeast where I always have 6 or 8 hours lag then away it goes. Its warming up a bit now until it gets going then I will cool back to 10 or 12 deg C.