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Making a yeast starter for a batch size of 250 litres

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  • Making a yeast starter for a batch size of 250 litres

    Hi to everyone, I d like to know how can I make my starter for 250 litres of wort, I have a magnetic stirrer and wanna know how many days of stirring and the volumens for do it. best regards
    Daniel
    DANNKEN

  • #2
    I would recommend that you don’t propagate you own. I believe you should buy it from an outside lab. Yeast propagation is a difficult task as everything wants to live in your product. It is very difficult, but absolutely critical that propagation is achieved aseptically.
    Drink the beer, destiny of the land.

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    • #3
      We prop our own yeasts all the time and never had any problems. Just follow aspetic techniques. For a very basic info check out books available via morebeer.com. They carry a couple of yeast prop books the best one is First steps in yeast culture. There is also a load of more in depth info out there on how to do this.. Try Siebel, beer science institute or ASBC for getting started with yeast proping in a micro.
      Bottoms Up!

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      • #4
        Even with agitation you will probably not hit a terminal cell count of more than 150 million cells/ml after 2 days.

        You will want to pitch to a minimum cell count of 10 million cells/ml, so after 2 days of agitation, you will need a minimum pitch volume of about 17 to 20 liters.

        You will also want to step up your propagation. Innoculate your wort with a minimum cell count of 10 million cells/ml. Every day and a half to 2 days or so, you will want add more wort, up to 10 times the current volume.

        In my opinion it is critical not to ever underpitch on a propagation, so step up everything slowly.

        Each time you step up make sure that you don't wait too long to add more wort, or you will get higher dead cell.

        If you don't have a haemocytometer or other way to count cells, it will be difficult for you to do precisely, but it is very possible.

        What are you propagating from? If you give me more information on your set up, I can give better advice.
        Steve G

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        • #5
          This can vary a little bit upon yeast strain but generally you should be able to purchase 1 liter of yeast slurry and use it to pitch about 5 liters of wort. Make sure the wort is sterile, autoclave it if you have to. If you autoclave, aerate the wort after this process to make sure enough oxygen is present. Let it ferment for several days, while agitating it with a stir plate and keeping it near fermentation temperature. After this use this six liters to pitch nearly 25-30 liters. Make sure aseptic techniques are used and make sure the wort is once again sterile and oxygentated. Let the yeast grow for several more days under fermentation temp and try to agitate if possible. This volume can then be used to pitch your 250 liter brewlength. You also want to make sure the wort you're using is fairly typical, around 10-12 plato. This propagation technique I've described above is conservative and could be modified after intial trial.

          Usually you can be more agressive on propagation and increase slurry tenfold until you have enough to pitch your brewlength (you need 25 liters). So if you really wanted to you could start with .25 liters, grow to 2.5 liters, and then again grow to 25 liters and use this to pitch 250 liters. I think you may want to start with 1 liter from your yeast supplier as smaller volumes will exist (homebrew shop) but they may not be the freshest of samples. If you go this route check the expiration dates.

          If you are confident in you aseptic techniques wort can be collected from prior brewday(s) and autoclaving can be avoided. Autoclaving is a good idea but aerating wort can be tricky and usually will involve some special equipment.

          Good luck!
          Mike Jordan
          Brewmaster
          Boxing Cat Brewery
          Shanghai, P.R. China
          michael@boxingcatbrewery.com

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