Agitation with pump

[shaunebersole]

I'm looking into doing our own props and need a cost effective way to agitate the yeast. I've read peristaltic pumps are best for managing yeast but we don't have 6+K to throw down for one right now (maybe there are cheaper ones?). The idea is to prop in a 1bbl FV for 20bbl pitchable using a flexible impeller pump to mix bottom to racking arm. Is the issue that an impeller would shear the yeast or concern over contamination or both? Has anyone tried this with success?

Thanks in advance!!

Cheers!

[Bryan Budahn]

I am also very interested in this technique! I was 'beer dreaming' last night and was thinking of dropping an aquarium pump into a 10 gal fermenter to step up our yeast for a 7bbl batch.

Has anyone tried this before?

[rdcpro]

I'm not sure you'd want a flexible impeller pump running for such a long period. But how about a pneumatic diaphragm pump? I have a nice Yamada food grade pump that would probably run continuously for a year at low flows. They are extremely low shear. You wouldn't need a whole lot of flow, I suppose, so what about one of the small Flojet beer pumps, like the Flojet G56 Beerjet? Infinitely variable, sanitary, made for beer...diaphragm pumps can usually pass solids fine, so suspended yeast wouldn't be a problem. I once used a large diaphragm pump to move lime slurry in a tank this way.

Regards,
Mike Sharp

[Yeast]

For agitation on such a small prop you can use the oxygenation/aeration to do the agitation. I simply pump sterile air through the bottom
this is in a 3bbl FV used as a prop.

you can reasonably expect to grow to 150-250 million cells per mL if you pitch the prop sufficiently
that would pitch 27bbl at 10 plato or 18bbl at 15 plato give or take if you hit 200 million