Refrigerating yeast starter

[beerguy2009]

I have made up a yeast starter that is currently on the stir plate. I was planning on brewing tonight but may not be able to due to a schedule change. If I put the yeast starter in the frig for a few days, will it negativly affect it? I would be able to use it on Sunday.

 

[stixobutta]

A lot I people put there starter in the fridge to force the yeast to fall out of suspension and then decant. I don't typically cold crash mine because I don't like the idea of constantly changing temps on the yeast. If you do, do it slowly and raise it back up slowly. I've left starters at pitching temp for several days before. The yeast should retain their viability. You could also step the starter if you needed to and that would keep them active till Sunday.

 

[Cpt_Kirks]

You can refrigerate the starter, or just let it finish and pitch it Sunday.

If you chill it, let it warm up before you pitch it.

 

[WoodlandBrew]

Agreed. Either is fine assuming the gravity of the beer it is pitched into is low and the wort is well oxygenated, but neither are ideal.

If you leave it at ambient it will proceed through the fermentaion phase and prepare for dormancy which means that the glycogen levels will be high, but the sterol levels will be low and there will be a lag phase before fermenting.

If you put it in the fridge the yeast will also move to dormancy, however the glycogen level will also be low if this is done durring the fermentation phase.

Viability will be absolutely fine either way, but leaving it out of the fridge until it has finished fermenting may be better. Typicaly 5-7 days.

Typical fermentation at ambinet graph:
http://woodlandbrew.blogspot.com/2012/12/yeast-cell-growth-observations.html

Data at ambient:
http://woodlandbrew.blogspot.com/2012/12/yeast-health-when-kept-at-ambient.html

data from refrigerated slurries:
http://woodlandbrew.blogspot.com/2012/12/refrigeration-effects-on-yeast-viability.html

 

[BassBeer]

I began my starter Tuesday night (1/8 ), let it ferment and settle out, decanted this morning (1/10) and stepped it up. I'll be brewing tomorrow so can I let it ferment for 24 hrs then cool, decant and pitch?

 

[beerguy2009]

So it sounds like it would be fine if I don't use it until Sunday. Thanks for all the quick responses. I am still hopeful that I can brew tonight as planned.