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General Category => Yeast and Fermentation => Topic started by: gmac on January 18, 2013, 11:36:24 AM

Title: Cold Wort - Warm Yeast
Post by: gmac on January 18, 2013, 11:36:24 AM
Any danger pitching room temperature yeast starters into cold wort?  At this time of year, it's probably 1 to 2 degrees above freezing in my garage and I sometimes make beer at the end of the day, chill it down to 70 or so with an immersion chiller and let it sit overnight in the cold to allow the hot break and hops to settle out before transferring to a bucket or carboy.  I've had good luck with this but now it's really cold and I'm wondering if there is any detriment to pitching room temp yeast into this cold wort.  Ideally, I would remember to put the yeast starter in the garage at the same time and let it get cold but sometimes I forget.

After pitching I move them to the basement that is a nice even 66 degrees.  I could let the beer warm up before pitching but I'd prefer to have yeast in there in order to compete if there are any bacteria etc that the star-san missed.

Thanks
Title: Re: Cold Wort - Warm Yeast
Post by: beersk on January 18, 2013, 11:40:03 AM
How cold is the wort? You don't want to pitch too low or the yeast will go dormant.
Title: Re: Cold Wort - Warm Yeast
Post by: denny on January 18, 2013, 12:31:29 PM
Supposedly cold yeast into warm wort is good, warm yeast into cold wort not so good....but I'll be damned if I can remember exactly why.
Title: Re: Cold Wort - Warm Yeast
Post by: Hokerer on January 18, 2013, 01:06:54 PM
Supposedly cold yeast into warm wort is good, warm yeast into cold wort not so good....but I'll be damned if I can remember exactly why.

Something about liquor on beer or beer on liquor....    oh wait
Title: Re: Cold Wort - Warm Yeast
Post by: beersk on January 18, 2013, 01:18:50 PM
Supposedly cold yeast into warm wort is good, warm yeast into cold wort not so good....but I'll be damned if I can remember exactly why.

Something about liquor on beer or beer on liquor....    oh wait
No, man, it's before...liquor before beer...
Title: Re: Cold Wort - Warm Yeast
Post by: davidgzach on January 18, 2013, 02:30:32 PM
I don't think it is ever a good practice to shock the yeast with cold to warm and dry to wet having a bad effect on the cell walls.  That being said, I truly have no idea about warm to cold.  If it were me, I would just wait for one or the other.  Bring the warm yeast in the garage to get cold and if you forget, then bring the cold wort in the house to warm up.  If you are sanitizing well, there should be no problems.

Dave
Title: Re: Cold Wort - Warm Yeast
Post by: snowtiger87 on January 18, 2013, 03:04:17 PM
Most recommendations I have seen is have your yeast within 10 degrees of your wort either way.
Title: Re: Cold Wort - Warm Yeast
Post by: denny on January 18, 2013, 03:21:35 PM
I don't think it is ever a good practice to shock the yeast with cold to warm and dry to wet having a bad effect on the cell walls.  That being said, I truly have no idea about warm to cold.  If it were me, I would just wait for one or the other.  Bring the warm yeast in the garage to get cold and if you forget, then bring the cold wort in the house to warm up.  If you are sanitizing well, there should be no problems.

Dave

I have done colder yeast to warmer wort for many years and hundreds of batches.  I've gotten excellent results and never any sign of "yeast shock".  AAMOF, I don't know if it even exists and I've read that it's actually preferable to do it that way.  Dr. Schmidlin, didn't you weigh in on this before?  The theory being that if you warm up the yeast they start consuming their nutrient reserves before they go into the yeast.
Title: Re: Cold Wort - Warm Yeast
Post by: speed on January 18, 2013, 05:05:43 PM
Supposedly cold yeast into warm wort is good, warm yeast into cold wort not so good....but I'll be damned if I can remember exactly why.
jeez denny, alzheimers moment?
Title: Re: Cold Wort - Warm Yeast
Post by: gmac on January 18, 2013, 05:13:31 PM
How cold is the wort?
Well, it's too cold to lager in the garage so I'm guessing it's just above freezing.
I brought the wort inside for a couple hours to let it warm a bit before I pitched.
I've pitched into cider that had ice in it and it worked fine but maybe it could have worked better.
Title: Re: Cold Wort - Warm Yeast
Post by: troybinso on January 18, 2013, 05:24:43 PM
If you pitch the yeast in very cold wort, it won't really stay in suspension, it will just fall down to the bottom of the vessel. Once it is on the bottom it is harder to get it started fermenting. I think you would be better off bringing the wort into the basement and let it sit there until it gets in the sixties and then pitch the yeast.
Title: Re: Cold Wort - Warm Yeast
Post by: davidgzach on January 19, 2013, 07:20:47 AM
I don't think it is ever a good practice to shock the yeast with cold to warm and dry to wet having a bad effect on the cell walls.  That being said, I truly have no idea about warm to cold.  If it were me, I would just wait for one or the other.  Bring the warm yeast in the garage to get cold and if you forget, then bring the cold wort in the house to warm up.  If you are sanitizing well, there should be no problems.

Dave

I have done colder yeast to warmer wort for many years and hundreds of batches.  I've gotten excellent results and never any sign of "yeast shock".  AAMOF, I don't know if it even exists and I've read that it's actually preferable to do it that way.  Dr. Schmidlin, didn't you weigh in on this before?  The theory being that if you warm up the yeast they start consuming their nutrient reserves before they go into the yeast.

I hear ya Denny.  I was thinking of more of an extreme.  Like pitching 34F yeast straight from the fridge in to 68F wort.  I can't see that being a good thing but I don't know the science.  (Plus I was well in to my super Noble hopped Pils when I commented last night, YUM!  ;D)  Tom?  a10?

Dave
Title: Re: Cold Wort - Warm Yeast
Post by: Mark G on January 19, 2013, 10:01:01 AM
I don't think there's much, if any, negative effect of pitching cold yeast into warm wort. I pull my starters out of the fridge, decant, and pitch immediately as my standard method. So you're taking about roughly a 30 degree temp difference. The yeast always perform great.
Title: Re: Cold Wort - Warm Yeast
Post by: denny on January 19, 2013, 10:23:28 AM
Supposedly cold yeast into warm wort is good, warm yeast into cold wort not so good....but I'll be damned if I can remember exactly why.
jeez denny, alzheimers moment?

Could be....I forget!  ;)
Title: Re: Cold Wort - Warm Yeast
Post by: denny on January 19, 2013, 10:24:29 AM
I don't think there's much, if any, negative effect of pitching cold yeast into warm wort. I pull my starters out of the fridge, decant, and pitch immediately as my standard method. So you're taking about roughly a 30 degree temp difference. The yeast always perform great.

Yeah, same method for me.
Title: Re: Cold Wort - Warm Yeast
Post by: davidgzach on January 19, 2013, 10:49:36 AM
I don't think there's much, if any, negative effect of pitching cold yeast into warm wort. I pull my starters out of the fridge, decant, and pitch immediately as my standard method. So you're taking about roughly a 30 degree temp difference. The yeast always perform great.

Yeah, same method for me.

Learn something new every day!  Thanks for saving me valuable yeast warming time.... ;)
Title: Re: Cold Wort - Warm Yeast
Post by: tschmidlin on January 21, 2013, 05:37:04 PM
First, let me say there are strain to strain variations and the research I am familiar with was done on S. cerevisiae strains.

It really depends on how cold the wort is.  If it is under 50F then you can induce the near-freezing response, which will have the cells doing all kinds of useless things (from a fermentation perspective) which just sucks energy out of them.  Since it is already at 66, dumping it into something at 55-60F should be more or less harmless.  There is the tendency to flocculate at colder temperatures, but the presence of glucose represses flocculation so I'm not sure which would win out - probably temp and strain dependent.  You can cold shock the yeast, but virgin cells (half of your culture) don't recover as well as mother cells.

Prudence would say to avoid it if you can.  If you can't, then RDWHAHB.