Yeast Starters

[smyrnaquince]

I am trying to understand yeast starters.

If I understand correctly, for a starter you pitch a vial of yeast into a "mini-wort" made with DME, keep it at the right temperature, stir it (stir plate or frequent swirling), and 24 hours later the yeast count has doubled. At that point, you pitch the starter into your wort.

My question:

Why won't the yeast count double if pitched directly into the full volume of wort? Why is the intermediate step of a starter needed?

 

[kombat]

Why won't the yeast count double if pitched directly into the full volume of wort?

They will. They'll more than double. However, with so few cells in such a large volume, they'll become stressed trying to multiply in one giant step from such a small count to consume all those sugars, and they'll produce off-flavours. If you pitch enough cells initially, they can simply grow modestly (i.e., no stress or off-flavours) and then quickly get to work on the wort.

Any off-flavours they might produce in the starter are irrelevant because ideally, you'll cold-crash the yeast and decant/discard the spent wort.

 

[Zoidberg]

Yea, some do not wait 24 hours and pitch whole stryer because as small of a portion it is. Ita over oxygenated plain wort and I don't like the idea of that in my final beer. I make my starter at leat five days before. Let it build up for 4 days then refrigerate over night, decant off wort, and pith just the yeast slurry at the bottom.

 

[catdaddy66]

Yeast starters are used to increase cell count to necessary (or more) amounts of viable cells. Too few and the yeast will get overworked, causing strange and undesirable flavors and such. I generally create a starter from my washed yeast as I do not know how many cells I'm starting with. I resisted doing starters initially but now I am washing the yeast cake from my brews and this saves me money while expanding my fermenting options with different varieties of yeasties!


Sent from my iPhone using Home Brew

 

[BrewerinBR]

Depending on the beer and the OG I am seeking I will often start building a starter 14 days in advance. Thus giving me time to add an increasingly higher gravity wort to the starter several times and grow more and stronger yeast.

 

[IronLion409]

Yea, some do not wait 24 hours and pitch whole stryer because as small of a portion it is. Ita over oxygenated plain wort and I don't like the idea of that in my final beer. I make my starter at leat five days before. Let it build up for 4 days then refrigerate over night, decant off wort, and pith just the yeast slurry at the bottom.

Do you have to allow the starter to warm up to room temp before pitching ?

 

[BrewerinBR]

yes ... otherwise you could shock the yeast....

I always try to get the starter decanted and then close to the pitching temp of the wort about 58 to 68 F

 

[IronLion409]

Great thanks

 

[Zoidberg]

I do let it warm up to a temperature closer to the worts. I've read that you want in no more than 10 degrees warmer than your wort.

Also, I've read quite a few times about yeast being colder than wort. I read a few posts on here as well as other sources that say it should be fine to pitch cooler yeast into warmer wort, just not vice versa. No experience personally though.

 

[planetscott]

Besides the off flavors, your beer may be under attenuated if you don't utilize a yeast starter. I had a fairly new brewer tell me his last batch had the extract twang. Turns out it was a Belgian Trippel kit that only had one package of dry yeast. I told him the twang was likely under attenuated beer. I told him, either start making yeast starters, or stop doing Belgian kit beers......Unless it was a Saison.