How long for starter on a stirplate

[HedgehogBC]

From Mr. Malty.com

Q: At what point do I pitch the starter into the wort?

A great deal of discussion rages over this topic. Should the starter be fermented completely, the spent liquid decanted, and the yeast pitched or should the entire starter be pitched when at the height of activity?

Most yeast experts say that when propagating yeast, moving at high krausen is optimal. The time of high krauesen can range anywhere from a few hours to twenty-four or more. It depends on the amount of yeast added to the starter wort, yeast health, temperature, and several other factors.

Doss says a starter made from an XL pack of yeast into 2 liters of wort will reach its maximum cell density within 12-18 hours. If you’re starting with a very small amount of yeast in a large starter, it can take 24 hours or more to reach maximum cell densities. For the average starter, let's just say that the bulk of the yeast growth is done by 12-18 hours.

I like to pitch starters while they're still very active and as soon as the bulk of reproduction is finished, usually within 12 to 18 hours. This is really convenient, because I can make a starter the morning of the brew day or the night before and it is ready to go by the time the batch of wort is ready.

Of course, if you have a large starter volume in relation to your batch of beer or a starter that was continuously aerated, then you probably don’t want to pitch the entire starter into your wort. Adding a large starter or a heavily oxidized starter to your wort can alter the flavor of the finished beer.

If you’re going to pitch only the yeast from the starter, make sure the starter attenuates fully before decanting the spent wort. The yeast rebuild their glycogen reserve at the end of fermentation and it is this glycogen that they use when preparing to ferment a new batch of beer. Separating the spent wort from the yeast too early also selectively discards the less flocculent, higher attenuating individuals in your yeast population. You may end up with a pitch of yeast that won’t attenuate the beer fully. Allow the fermentation to go complete cycle, chill, decant the beer and pitch just the yeast.

So apparantly, it is better for the yeast to pitch at high krauesen. Huh. I still like my method, because I still don't like the idea of adding oxidized wort to my beer.

[DBear]

Thanks for all the responses.

Mr Malty calc: 1.060, 96% viable yeast, stirplate = 1 vial in 1l. On one of the recent Brew Strong QandA shows JZ talking about starter wort oxygenation and suggested pitching 1l or under (I think).

-Cheers

[Nyakavt]

If I am brewing on Monday, I have been making my starters on Friday night. The whole time on the stirplate. Monday morning I will put it in the fridge to floc out the yeast.

See...this is the part I don't get. Some say ( Jamil being on of them I think ) to pitch yeast at high krausen. Others, like you, ferment it out, chill, decant and pitch that yeast. What is the best method and why?

Sorry to thread jack DBear, but I think this helps answer your question too.

You can grow a large starter, decant and pitch at high krausen by putting some 'wake up' wort on your decanted yeast the morning of brew day. The 'wake up' starter is not enough to grow new yeast (0.5-1L), so you do not want it to ferment out completely. Also it's a good idea to keep this wake up starter at or below pitching temp to avoid the lag from thermal shock. I'll do the wake up thing if I'm pitching an oldish slurry, otherwise I just pitch the decanted yeast.

Another option (especially for lagers due to the pitching temp) is to run off a small amount of wort post boil and pitch the yeast into that while the rest of the batch chills down to pitching temps in the fridge overnight. The next morning pitch the whole thing into the main batch of wort.

[mauser98k98]

Well why would it matter if you ad oxidized wart from a starter. Im going to add oxygen after the boil anyway.

From Mr. Malty.com

Q: At what point do I pitch the starter into the wort?

A great deal of discussion rages over this topic. Should the starter be fermented completely, the spent liquid decanted, and the yeast pitched or should the entire starter be pitched when at the height of activity?

Most yeast experts say that when propagating yeast, moving at high krausen is optimal. The time of high krauesen can range anywhere from a few hours to twenty-four or more. It depends on the amount of yeast added to the starter wort, yeast health, temperature, and several other factors.

Doss says a starter made from an XL pack of yeast into 2 liters of wort will reach its maximum cell density within 12-18 hours. If you’re starting with a very small amount of yeast in a large starter, it can take 24 hours or more to reach maximum cell densities. For the average starter, let's just say that the bulk of the yeast growth is done by 12-18 hours.

I like to pitch starters while they're still very active and as soon as the bulk of reproduction is finished, usually within 12 to 18 hours. This is really convenient, because I can make a starter the morning of the brew day or the night before and it is ready to go by the time the batch of wort is ready.

Of course, if you have a large starter volume in relation to your batch of beer or a starter that was continuously aerated, then you probably don’t want to pitch the entire starter into your wort. Adding a large starter or a heavily oxidized starter to your wort can alter the flavor of the finished beer.

If you’re going to pitch only the yeast from the starter, make sure the starter attenuates fully before decanting the spent wort. The yeast rebuild their glycogen reserve at the end of fermentation and it is this glycogen that they use when preparing to ferment a new batch of beer. Separating the spent wort from the yeast too early also selectively discards the less flocculent, higher attenuating individuals in your yeast population. You may end up with a pitch of yeast that won’t attenuate the beer fully. Allow the fermentation to go complete cycle, chill, decant the beer and pitch just the yeast.

So apparantly, it is better for the yeast to pitch at high krauesen. Huh. I still like my method, because I still don't like the idea of adding oxidized wort to my beer.

[dunleav1]

I make a starter 4-5 days before I brew. The size of the starter is calculated from mrmalty.com.
I run the starter on the stir plate for 48 hours. I then put it in the fridge until brew day.
I run the starter 10 degrees above my target fermentation temperature.

On brew day I collect 500ml after the first fifteen minutes of boil (prior to hopping).
I then chill then to my target fermentation temperature. I decant my starter and pitch the 500 ml to the flask.
I then put that back on the stir plate and pitch the entire thing into the final wort.

I have been getting great attenuation for every yeast I done with this method.

[brewinhard]

[quote="mauser98k98"]Well why would it matter if you ad oxidized wart from a starter. Im going to add oxygen after the boil anyway.

Adding oxidized wort and adding oxygen to chilled wort are two different things. Oxidized wort will lead to off flavors in your finished product (quite unnoticeable if adding a small amount ie 1 L) and lead to a less stable product over time (shelf life). Adding oxygen (aeration) to your chilled wort is necessary for proper yeast health during fermentation.

[Guerra]

- Is there some generalized rule of thumb for stir time or are you determining based on OG, Starter size, yeast viability/amount?-

The size of the starter, the number of "vials" that I will be pitching, and how I will be using the starter all contribute to how long I leave my starters on the plate.

I simply keep watch on the starter. The krausen will rise, and fall just like a full size fermentation. I am ass-u-me-ing that when the krausen has fallen, the starter has completely fermented.

For large starters >3 liters, I allways decant before pitching and want a completly fermented starter. When pitching a single vial in 3 liters of wort, my experience is that it takes about 48 hrs to completly ferment. If you are pitching 2 or more vials the starter seems to ferment out quicker and will require less time on the stir plate ~36 hrs.

If I am using a small starter (< 1.5 liters, I do not decant before pitching). When I make a small starter I am usually pitching the whole starter. So in that case I want the starter to be at high krausen when I pitch. So in this case I pitch after about 12 hrs on the plate.

Orlando

[dunleav1]

Well why would it matter if you ad oxidized wart from a starter. Im going to add oxygen after the boil anyway.

Adding oxidized wort and adding oxygen to chilled wort are two different things. Oxidized wort will lead to off flavors in your finished product (quite unnoticeable if adding a small amount ie 1 L) and lead to a less stable product over time (shelf life). Adding oxygen (aeration) to your chilled wort is necessary for proper yeast health during fermentation.

For what I do (listed post above) 500 ml of 3 hour airated wort in a 19L (5 gallons) wort is about 2% and is nothing that can be tasted.