I've recently been hired part time at a local brewery (10bbl system) to develop and implement a QC/QA program. My background is molecular biology, so the lab side of things are well within my comfort zone.
However, part of the general plan is to also put together a yeast propagation system. I have no problem slanting, plating, and growing up lab-sized cultures, but I have no experience with industrial-scale microbiology.
I've done a lot of reading (here and other places) and I think I've put together a general plan for propagation, but I was hoping you guys could provide a bit of feedback.
Starting from slants, I can easily grow up ~500mL of culture in sterilized wort in the lab within a few days.
After that, I was planning on pitching this into 50-100 liters of oxygenated wort in a 15bbl conical fermenter.
From this point, my plan was to double the volume in the fermenter at least once if not twice (each after 24hrs) before pushing the whole thing into a 20bbl batch.
Unfortunately, we don't have the budget to get a purpose-built propagator, so I was thinking of installing a SS carb stone in the lower port of the fermenter and periodically hitting it with oxygen to mix the culture and maintain a high level of oxygenation.
As far as this goes, I figured I'd have to play around with frequency and duration of the oxygen pulses to optimize growth rate.
I have a few lingering questions, though. First off, does this seem reasonable or am I way off base?
Second, does anyone know of any affordable solutions for automating (at least somewhat) the pulses of oxygen and/or do you have any general guidelines for how frequently it will need to be oxygenated (unfortunately a DO meter is still on the wishlist)?
Finally, should I be concerned about pushing the 'propagation beer' into a production batch? I suppose I could always crash cool the tank and try to just pull a yeast slurry out instead of pushing the whole batch.
I definitely appreciate any feedback you guys can provide and I am also very grateful for all of the excellent info I've gleaned from the forum so far.
However, part of the general plan is to also put together a yeast propagation system. I have no problem slanting, plating, and growing up lab-sized cultures, but I have no experience with industrial-scale microbiology.
I've done a lot of reading (here and other places) and I think I've put together a general plan for propagation, but I was hoping you guys could provide a bit of feedback.
Starting from slants, I can easily grow up ~500mL of culture in sterilized wort in the lab within a few days.
After that, I was planning on pitching this into 50-100 liters of oxygenated wort in a 15bbl conical fermenter.
From this point, my plan was to double the volume in the fermenter at least once if not twice (each after 24hrs) before pushing the whole thing into a 20bbl batch.
Unfortunately, we don't have the budget to get a purpose-built propagator, so I was thinking of installing a SS carb stone in the lower port of the fermenter and periodically hitting it with oxygen to mix the culture and maintain a high level of oxygenation.
As far as this goes, I figured I'd have to play around with frequency and duration of the oxygen pulses to optimize growth rate.
I have a few lingering questions, though. First off, does this seem reasonable or am I way off base?
Second, does anyone know of any affordable solutions for automating (at least somewhat) the pulses of oxygen and/or do you have any general guidelines for how frequently it will need to be oxygenated (unfortunately a DO meter is still on the wishlist)?
Finally, should I be concerned about pushing the 'propagation beer' into a production batch? I suppose I could always crash cool the tank and try to just pull a yeast slurry out instead of pushing the whole batch.
I definitely appreciate any feedback you guys can provide and I am also very grateful for all of the excellent info I've gleaned from the forum so far.
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