Yeast machine

[McMullan]

Good morning Brewers,

I’ve been testing my recently finished yeast harvesting machine.

The main idea behind it was to design something that would allow home brewers to culture a yeast strain indefinitely, without the inevitable colonisation by wild yeast and bacteria.

Please take a look, if that sort of thing is of interest to you.

https://youtu.be/A58kNu3t94w

[Jocky]

That's quite cool, can you explain more about it and how it works?

[McMullan]

It’s a 'closed system' for culturing pure yeast and inoculating sterile wort. The air filter stops airborne microbes (wild yeast and bacteria) contaminating the starter wort. The stirred culture is a 1.5L starter (more than I need for a 23L brew). When it’s done, 500ml of the culture is pumped to another 1L batch of sterile wort, inoculating the next 1.5L starter.

[wally]

Would you mind putting up a parts list? I'm really fascinated by this.

[McMullan]

Would you mind putting up a parts list? I'm really fascinated by this.

No, I don't mind, wally.

Someone has made a valid suggestion that would improve the system. And I need to upgrade the peristaltic pump, too. I'll put something together when this is sorted.

Thanks for the interest.

[naturals]

Neat system! One question though:

The stirred culture is a 1.5L starter (more than I need for a 23L brew)

Do most people not use circa 2L for a 23L batch? I know it varies based on yeast / OG but I've always thought 2L was a safe rule of thumb for all beers.

[McMullan]

Neat system! One question though:

The stirred culture is a 1.5L starter (more than I need for a 23L brew)

Do most people not use circa 2L for a 23L batch? I know it varies based on yeast / OG but I've always thought 2L was a safe rule of thumb for all beers.

1L of fresh healthy yeast is sufficient for a typical ale, IME, and achieves full attenuation in a few days. Some brewers use a lot less.

[Clibit]

Does anyone really know the correct pitching rates, and the number of cells they actually pitch, or are we all just clutching at spores!

Isn't it all about getting in the right ball park? Are 2 litre starters geared to making sure you don't under pitch? Brewlabs slants are added to 300ml starters which apparently works cos the yeast is healthier or something. How is it so different? Does anyone really understand yeast?!

[McMullan]

Does anyone really know the correct pitching rates, and the number of cells they actually pitch, or are we all just clutching at spores!

Isn't it all about getting in the right ball park? Are 2 litre starters geared to making sure you don't under pitch? Brewlabs slants are added to 300ml starters which apparently works cos the yeast is healthier or something. How is it so different? Does anyone really understand yeast?!

I agree clibit. Yeast are living organisms and fermentation is a biological process. The variables are many. Any guidelines can’t be any more than guesstimates for a specific situation. We have to determine if it works empirically ourselves in our own brewing environment. We should be bothered more about yeast health, viability and vigour. I’m not sure why yeast slopes seem to be more viable and vigorous. Perhaps a liquid environment is more stressful? Chemical reactions would occur more easily in liquid, I guess. Wild yeast survive on surfaces exposed to air. Who knows?

[McMullan]

If you needed to make a yeast starter bigger than 1L, e.g. for a bigger batch or a big beer (IRS or BW) or a lager, that’s easy to do using this machine. You’d simply build up the pure yeast slurry in one bottle over a number of days; cold crashing and pouring off spent wort between top ups. It’s easy and quick to set up. Sterilised wort can be prepped in advance and stored for months.

[Hanglow]

Like that

[demig]

Looks nice, got some
Schott bottles in the garage so I think I have the makings of a Christmas project now!

[McMullan]

Glad you’re liking it, Chaps. That’s what it’s about. Upgrading home brew practices to get better, cheaper and better than phantasmagoric yeast to ferment better beer

[McMullan]

[demig]

Another peristaltic to pump direct into sealed fv.....