Yeast pitch calculator question

Discussion in 'General Brewing Discussions' started by philjohnwilliams, Dec 30, 2018.

  1. philjohnwilliams

    philjohnwilliams Well-Known Member

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    For those who use the yeast pitch calculator for calculating starters, which growth/aeration model do you choose? I grow my starters on a stirplate and have been using the C. White - stirplate model with good results, but I have noticed that choosing the Braukaiser stirplate model suggests a growth rate almost twice that. What are people using and how are your results? I am happy with the results I am getting and I am seeing active fermentation on my lagers (at 50°f ) in about 8 hours, but if I can be getting good results with smaller starters/fewer steps that would be great too.
     
  2. BOB357

    BOB357 Well-Known Member

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    I have used Kai's calculator in the past with good results and see no reason to do larger starters than he recommends.

    Many people are using the, "shaken, not stirred" starter method, believing that vitality is more important than cell count. They use a relatively small starter and pitch it at high krausen. People who use this method say it produces excellent results.
     
  3. Mase

    Mase Well-Known Member

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    I’ve always used the Braukaiser setting on this site. I start my yeast starters around 6pm the night before brewday and pitch around noon (end of brewday) and have fermentation starting with 3-4 hours and always great results.
     
  4. philjohnwilliams

    philjohnwilliams Well-Known Member

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    Are you decanting your starters or pitching the whole flask?
     
  5. philjohnwilliams

    philjohnwilliams Well-Known Member

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    Before I built my stirplate I used the shaking method, and while it worked for me I must say I find it eadier for me to set my flask on a stirplate and leave it until it is done.
     
  6. Mase

    Mase Well-Known Member

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    I mostly pitch the whole lot. My crude logic believes that the yeast still in suspension have a distinct role and as such, so should get passed to their successive generations.
     
  7. BOB357

    BOB357 Well-Known Member

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    The shaken not stirred method is different than shaking a starter every time you walk by it.

    Pour a liter of starter wort with yeast in a container, a 1 gallon jug works well, put the lid on and shake vigorously until 80 or 90% turns to foam. Replace the cap with a piece of sanitized foil and allow it to sit until it reaches high krausen in a few hours and then pitch it all. No further shaking is needed.
     
  8. philjohnwilliams

    philjohnwilliams Well-Known Member

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    That is not a method I was familiar with. This will favour vitality over cell count?
     
  9. BOB357

    BOB357 Well-Known Member

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    Yes, it will. Among those who use it is Denny Conn. He says he hasn't used his stir plate since trying this quite awhile back.
     
  10. ChicoBrewer

    ChicoBrewer Well-Known Member

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    Sounds like what bakers call proofing.
     
  11. BOB357

    BOB357 Well-Known Member

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    More than proofing, it's a vitality starter.
     
  12. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    I use the Braukaiser setting. From everything I been able to verify, it's very accurate.

    The "shaken not stir" method is supposed to reduce yeast shear. But I have not been able to find any evidence of "shearing" with stir plates. But if your worried about it, just stir a little slower. I can't see how this would be better for lagers and it's nearly impossible to use this method in a professional setting.

    Yeast shear produces petite daughter cells and can produce off flavors that propagate to later generations. It's caused by mechanical means and is usually associated with rough handle of yeast such as centrifuges or high pressure pumps. From everything I can find on it is that it's a minor problem, if at all, for homebrewers.
     
  13. BOB357

    BOB357 Well-Known Member

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    I haven't had any problems with shear either. Thinking you may need to have a turbocharged stir plate to experience that :) I still spin up my starters.
     
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  14. Hawkbox

    Hawkbox Well-Known Member

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    Honestly I make up numbers and then just do a 2-3 liter starter on a stir plate. A lot of the stuff I read around yeast starters reads like cargo cultism to me.
     
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  15. Trialben

    Trialben Well-Known Member

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    I used to use yeast calculator but now just do a 2.5 Lt starter for lagers and 1 -1.5 lt starter for Ales. I used Braukaiser setting in calculator.
     
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  16. Nosybear

    Nosybear Well-Known Member

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    There is quite a bit of voodoo going on there.... Without actually counting cells and testing for viability, you really have no idea of how many cells you actually have. I do starters, size depending on how I'm fermenting (lager vs. ale) and how big the beer. A 1 liter starter is routine, a 2-liter starter is for lagers and big ales and a 3-liter starter is for high percentage (9% or greater) ales and bigger lagers. I use a stir plate and despite owning a microscope and hemocytometer, have never counted the cells. Beer's good so appealing to my fundamental sense of laziness, I don't count. But I do make starters.
     
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  17. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    It’s really not “voodoo” as much as a guesstimate. With known growth rates in starters, a brewer can have a fairly accurate cell count. At some point you will hit maximum cell density in starters, any new biomass (the tanish/pink stuff that settles out) can be assumed to be not only new cells, but have good viability.

    The important thing is whatever method you use to estimate cell count/viability/biomass, don’t switch methods until your comfortable and happy with results in the finished beer, then stick with it unless something comes along that’s better.

    This is one area in brewing where there can a lot of leeway and still have excellent results.
     
  18. GrimBeaver

    GrimBeaver New Member

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    But... that's all dependent on having an accurate starting cell count. One of the biggest variables is the handling of the yeast before it got to you.
     
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  19. Nosybear

    Nosybear Well-Known Member

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    Yep. Variables are initial cell count, amount of nutrient (read starter volume) available, growth rate, how many cells are decanted with the "starter" beer... It isn't voodoo, sure, but it's damned complex. The simplified model the yeast calculator uses gets close enough for homebrew and since I don't want to risk contamination through handling my yeast nor do I want to count cells, I'll continue to use it. Having sufficient yeast cells matters but I can't even get a consensus on how many are sufficient! As with most things Homebrew, try stuff, keep what works and throw out what doesn't. For my brewing, the calculator works.
     
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  20. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    Yes and no. If your starter hits maximum cell density, then you can have a fairly accurate count. If your building from an unknown yeast count from a slurry or you are in doubt about the count in a fresh pitch, you could build it in up in steps. The first step could be a 1/2 liter starter, which takes about 10 billion cells to hit maximum density of 80 billion cells. A tablespoon of washed or even yeast mix with trub would most likely exceed that count, even several weeks old if properly stored.

    If you can grow yeast with trub free wort, you can measure the volume of the yeast. Lager yeast cells are slightly larger than ale yeast cells, so it's a rough estimate, but 1/4 cup of yeast slurry equals roughly 250 billion cells. This number is base on numbers from Wyeast/White Labs. It's an easy number remember .25 cups = 250 billion cells. When pros re-pitch they usually measure the yeast by volume or weight. Occasionally the hemocytometer gets broken out to verify, but even the hemocytometer cannot measure vitality very well.

    Most of this is interesting and in the past I paid close attention to counts, but now I just use the starter calculators, I have no reason to believe that they are not accurate enough.
     

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