Step-up starter for bottle harvested yeast

Discussion in 'General Brewing Discussions' started by mrskittle, Jul 12, 2020.

  1. mrskittle

    mrskittle Member

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    I LOVE Oberon from Bell's Brewery in MI and have been dabbling a bit with a "clone". One way I'm trying to stay true to the ingredients is to get some yeast from the bottles. I did try this before with a 2 gallon batch and it worked great. The difference is that I used LME in the starter last time and this time I'm using LME. The other difference is that I'm going for a full 5 gallons this time. I feel "OK: about what I'm doing, but I'd rather feel "SOLID" about it. Hence why I'm here looking for some validation. So here's what I've got going on.

    I used the dregs from 3 bottles of Oberon in the initial step. Since Oberon is a seasonal brew, I'm assuming the yeast is still pretty viable. I'm just using a half-gallon growler and swirling it through the day. For the first step, I boiled 1 quart of water and added 3 oz of wheat DME to get me to about a 1.030 wort. I put 1 pint of that into the growler with the bottle dregs. I let that sit 3 days and then cold crashed it, decanted the wort, and moved onto the second step-up. The "used" wort came in at about 1.008 so I know that yeast was busy.

    For the second step I wanted to increase the gravity and volume of the wort so I went for about 1.5 pints of 1.040 wort. I did this step today.

    My big question here is: do I need to do a third step-up in another few days to something like a quart of 1.050? How can I be sure that I've grown enough yeast to successfully ferment a full batch?

    I need to find some resources to learn more about yeast. The details about pitching rate and such haven't sunk in very well from what I've studied so far. Any suggestions? I know there's a book simply called "Yeast" but is it geared towards a professional or hobbyist?
     
  2. Craigerrr

    Craigerrr Well-Known Member

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    I hate to steer you away from BF, but Brewfather has a great calculator for building up yeast. If there is a similar calculator here, I just haven't seen it. Truly the only way to get an accurate count is with equipment that none of us homebrewers would likely ever invest in. I know enough about the subject to tell you that I don't know enough about the subject.
     
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  3. mrskittle

    mrskittle Member

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    Its been about 2 days since I stepped up to the second level starter. It has seen high Krausen and the yeast is starting to settle out.

    There is a calculator here on BF but all of them I have seen require you to enter a volume for the yeast. Since I dumped it out off bottles and straight into a growler, I don't know the volume of yeast cells.
     
  4. Mark Farrall

    Mark Farrall Well-Known Member

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    If it's working at the volume you've got you've already cleared the tallest hurdle. Just step up your starter 10 times the volume or to your normal starter size, whichever is smaller.

    In the calculator here you can use the slurry option for the yeast type. I just eyeball the amount of slurry in the bottom, it doesn't need to be that precise. Once you're using the yeast after a full brew you may want to decrease the slurry density to account for the protein and hop material, but if it's been LME/DME up to this point it's relatively pure so just use the default value of 1.
     
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  5. thunderwagn

    thunderwagn Well-Known Member

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  6. mrskittle

    mrskittle Member

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    Thanks for the tip of using a default of 1. I'll have to give the calculator another try.

    Thanks for the links to Bells. They make it sound so easy. No overthinking it or anything...

    Chances are I've got plenty of yeast after the second step up. There's a good 1/4 inch cake at the bottom of the growler at this point. Just for the sake of it, I'll probably decant most of the wort and put the rest in a vessel that has graduated measurements. I'd be curious to get an estimate of how many cells I've got.


    What, generally, are the consequences of pitching too little or too much yeast? My understanding is that too little can lead to a stalled fermentation but I'm not sure what happens if you pitch too much.
     
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  7. Mark Farrall

    Mark Farrall Well-Known Member

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    As yeast ferment they use up some of their own cell materials. The more of these reserves they use, the more likely they are to become stressed which then makes them more likely to create off flavours.

    The most common reason for being stressed is there's not enough cells for the amount of sugar to ferment. So they have to keep fermenting for longer, running down their reserves. Another reason is they aren't healthy enough to start with (the previous fermentation used up much of their reserves, or they were stored for too long before use).

    Pitching too much is generally a problem if you've got a yeast that creates fruity or spicy notes. In that case pitching too many may mean it's less likely to create those flavours.
     
  8. Hawkbox

    Hawkbox Well-Known Member

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    At homebrew levels I would hazard unless you are severely high or low it's not something to worry to much about.
     
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  9. Trialben

    Trialben Well-Known Member

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    I'd overbuild your starter pitch rather than underpitch.

    Yeast dependant of course let's say it was a wheat beer yeast I'd underpitch as well as kviek.
     
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  10. Mark Farrall

    Mark Farrall Well-Known Member

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    And just to contradict myself, I heard a completely plausible argument that overpitching may be more likely to create the esters than not. Something to do with when yeast consume particular enzymes (alcohol acetyltransferases), they either use it for cell division or for ester creation. If they're dividing they're not using it for ester formation. There's a few papers mentioning both interactions (in their summaries, I'm not dredging through the main text), so still plausible.

    It also fits my experience. As a small batch brewer I'm often overpitching and my Belgians always have more esters than I'd prefer. But I really haven't done enough to say that my experience is anything more than a few random data points.
     

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