Yeast pitch questions

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brew703

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I have been brewing for almost a year now. I have made starters before but mainly use dry yeast. With that said, I just can't seem to grasp the concept on how to measure and pitch the required amount of yeast.

I have a stir starter stir plate with a 2L flask. The last couple times I've made a starter I got a good vortex early on then after about 8-12 hrs there is barely any vortex. At this point in the process the yeast still is somewhat in suspension, the color is cream looking but there is not a lot of movement.

I allowed my last starter to go 24 hrs, and with no vortex I pulled and placed in the fridge. Once all the yeast settled, there was barely any yeast at the bottom. It basically looked like there was no growth.

I will be brewing either Friday or Saturday and plan on starting my starter tonight. According to Brew United's calc, I chose a target pitch rate of .75 million/ml, overbuild cell count of 125 billion. The calculator provides a 70% viability. Volume of water at 1L and 101 grams of DME. Pitch amt is .405L and harvest amt of .595L.

I've read numerous posts about making starters, etc but I still cannot grasp how to measure out the required amount needed. It seems like some measure out while the yeast is still in suspension and most cold crash, decant then pitch.

With that said, would I remove the flask from the stirplate, measure out .405L while the yeast is still in suspension, cold crash then pitch the remaining amount? or do I simply take the flask, cold crash, decant then measure out
.405L then pitch? Or do I really need to cold crash? Could I just measure out what I need and pitch that amount?

If I convert liters to ounces, .405L equates to 13.7oz. I'm just trying to figure out the process so I can get this right.

I'm just really confused on this subject. I've been trying to understand the concept but the more I read the more I get confused.

I'm hoping someone can guide me in the right direction.
Thanks.
 
Pour off the volume you are going to save while the yeast is in suspension. The yeast cells will be evenly distributed throughout the total volume of the starter wort/beer.
 
It does look like the starter is finished or finishing up. No damage would be done by leaving it on the stir plate.
 
Not really scientific, but it works well for me. I use White labs yeast as a rule and saved several of their vials before they went to the new packaging.

As a rule, the vials were about 40% settled out yeast. I do a starter of the proper cell count plus another 100B cells. When the starter has finished (usually about 36 hours) I cold crash and then decant off most of the clear liquid. I then fill a vial that has been sterilized with 70% isopropyl alcohol. Once the yeast has dropped out I compare the volume of settled yeast to the normal 40% and assign a cell count approximation. I mark that and the date on a label.

I try to underestimate the cell count by about10% to avoid under-pitching. My understanding is that any negatives associated with over pitching will only be evident when re-pitching. Since you are harvesting from a starter I see no problem with the higher cell count.
 
Starter has been on the stir plate for 48 hrs. I harvested the amount noted which translated to 20 oz that I poured into mason jars while the yeast was still in suspension. Took the remaining amount and pitched.
First issue is I overfilled my fermentation bucket and when I added my yeast I forgot to cold crash, decant. There's probable less than a 1/4" headspace remaining.
I pitched everything. Guess I was in a rush and forgot.
My question is since I didn't decant how will this effect the end result?

Also once the yeast settles should I remove some of the wort to allow more headspace?
 
Not cold crashing and decanting the remainder of the starter will have no noticeable affect on your beer. You will need to fit a blow off tube on your fermentor though. Even with the fermentation in the low 60°F range there will be krausen emerging. Setting the fermentor in a tub will help mitigate the cleanup time.
 
Already have the blow off tube attached. I should have allowed more head space. I normally do. Not sure what I was thinking.
Also have the bucket sitting in a two inch pan. Hope that will contain most of the mess.
I'm gonna try and maintain ferm temp of 62. Prob will not do much good but will try.
Note to self. Don't rush and don't get distracted on brew day!
 
The last couple times I've made a starter I got a good vortex early on then after about 8-12 hrs there is barely any vortex.

Just to clarify, when you use the term "vortex" are you referring to the kraüsen?

Vortex: "a mass of whirling fluid or air, especially a whirlpool or whirlwind."
pbTX57T.jpg



Kraüsen: "the foamy, rocky head of yeast that forms at the peak of fermentation."
Batch-1-Oktoberfest-Joseph-Schwab-2014-05-081.jpg
 
Just to clarify, when you use the term "vortex" are you referring to the kraüsen?

Vortex: "a mass of whirling fluid or air, especially a whirlpool or whirlwind."
pbTX57T.jpg



Kraüsen: "the foamy, rocky head of yeast that forms at the peak of fermentation."
Batch-1-Oktoberfest-Joseph-Schwab-2014-05-081.jpg

Vortex not the foam.
This time, at about the 8-12 hr mark there was no vortex, but I could see the yeast particles moving around. The krausen was beginning to form at this point. At about the 24-36 hr mark when the krausen dropped, the vortex appeared again.
 
Does anyone have a photo of the harvested amount from the starter once transferred to a mason jar? just curious to see the amount once settled.
I ask because the harvested amount I have really does not seem like enough to use to make a new starter and build up to harvest more.
 
Vortex not the foam.
This time, at about the 8-12 hr mark there was no vortex, but I could see the yeast particles moving around. The krausen was beginning to form at this point. At about the 24-36 hr mark when the krausen dropped, the vortex appeared again.

The huge vortex isn't necessary. As long as your stir plate is able to keep the yeast in suspension and stir the wort to keep oxygenating, you'll be fine. The only reason I can think of that you can't see the vortex during high krausen is because the krausen itself is blocking the view. It's probably still there, just under the krausen.

Does anyone have a photo of the harvested amount from the starter once transferred to a mason jar? just curious to see the amount once settled.
I ask because the harvested amount I have really does not seem like enough to use to make a new starter and build up to harvest more.

If you post a picture here, I'm sure we can help you determine if there is enough.
 
brew703, don't worry bud. **** happens. I don't have enough experience yet to guarantee that everything will be fine, but we keep learning, right?
 
I can say that I'm pretty sure I over-pitched. Yesterday afternoon there was still some air lock activity, so that makes a week of active fermentation. The bubbling was not much but it was there. Not sure what affect this will have on the end product. I will be checking the gravity today and my initial plan is to rack to secondary and re-use the yeast cake for a batch that I plan to brew next Friday. I was going to leave the yeast cake in primary and keep in my ferm chamber until I am ready to use it next Friday but I really think I should transfer the yeast cake to mason jars.

I've read where the yeast cake will be too much so I may check Mr Malty and see what it recommends and transfer that amount to mason jars.

I was going to simply scoop some slurry out (with a sanitized spoon) and pitch directly on top of what's left but my primary is a mess from the very active fermentation and the fact I over-filled my bucket.

Live and learn I guess. Just hope the current batch will be drinkable.
next time I make a starter, I will cold crash and decant most of the liquid before pitching. Adding in excess of 20 oz was way too much. The entire starter process has been a baffling experience to say the least. Although when I pitched the yeast, I had active fermentation in 6 hrs or so which is a first for me.
 
Gravity check: 1.017 I'll recheck in two days they rack to secondary and harvest the yeast cake for Friday.
 

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