Yeast Count: Initial Count and Starter Size

[jamilz]

The mr. malty calc has a couple of built in limitations. First is that it will not recommend more than 6 'yeast packages' worth of growth. The reason for this is that you want to ensure that the starter finishes quickly so that you don't end up growing other bugs or yeast instead of the yeast you are trying to grow.

That is completely wrong. The reality is that there is a limit to how much growth you are going to get in starters. You're not going to get unlimited growth. At a certain point you are just fermenting and making beer, not growing more yeast. The calculator takes this into account and doesn't let you waste starter wort for zero additional cells.

It would be better to ask than to just assume stuff that isn't correct.

[jamilz]

Another consideration to remember, is that even if you can make your starter really big, you never want the cell count to grow beyond 10x its current size.

Again, not really true. As long as you are growing them using appropriate nutrition/conditions, then there is no reason to put such a limit on it.

However, you're not going to get 10X (doublings) growth in a starter at home.

[Nyakavt]

The mr. malty calc has a couple of built in limitations. First is that it will not recommend more than 6 'yeast packages' worth of growth. The reason for this is that you want to ensure that the starter finishes quickly so that you don't end up growing other bugs or yeast instead of the yeast you are trying to grow.

That is completely wrong. The reality is that there is a limit to how much growth you are going to get in starters. You're not going to get unlimited growth. At a certain point you are just fermenting and making beer, not growing more yeast. The calculator takes this into account and doesn't let you waste starter wort for zero additional cells.

What part is 'completely wrong'? The calculator jumps to 2 vials or smack packs needed after the '# of vials needed without a starter' gets above 6. Is there some set of inputs I can use on the calculator to get a different result than this?

Maybe the reason you put the limitation in the calc was to avoid wasting starter wort, but since you don't talk about this in the FAQ or in the calculator it's hard to guess why. Apologies if I've missed it somewhere. My thinking was that if you pitch a small amount of yeast into a large amount of starter wort it would take a long time to ferment and would be more prone to contamination from other 'stuff'. This is especially apparent when growing from a slant since the starting count is so small, and a first step of say 200 mL would take quite a while to ferment out. Are you saying that this is not a concern, and the only issue is the wasting of starter wort?

It would be better to ask than to just assume stuff that isn't correct.

What's with the attitude? I'm trying to relay the information as I understand it, should I run everything by you before posting?

[Nyakavt]

Another consideration to remember, is that even if you can make your starter really big, you never want the cell count to grow beyond 10x its current size.

Again, not really true. As long as you are growing them using appropriate nutrition/conditions, then there is no reason to put such a limit on it.

However, you're not going to get 10X (doublings) growth in a starter at home.

Is this the result of new research you've done for the book? From your FAQ:

The size ratio of one step to the next can affect the health of the yeast and the amount of cell growth. A very large step can result in a change in yeast metabolism, where the sugars that are fermented last can fall out of favor with the yeast. The yeast become lazy and subsequent generations can become lower attenuating.

Making a greater number of small steps increases the chance of contamination. Every transfer, every feeding, every bit of handling you do increases the chance of contamination. Five to ten times the size of the prior step is considered correct. You should try to balance the practical considerations of handling, sanitation, and cell growth.

[jamilz]

For the calculator you can use the growth slider to adjust if you want to use a larger starter and less packages of yeast or a smaller starter and more packages. It has a limit on the maximum amount of growth, because past a certain point you are not growing any more yeast even though you make a bigger starter.

On the other subject I think folks are mixing two different things. There is a suggested 10x STARTER size limit and there is 10x GROWTH. 10x growth is unrealistic in a homebrew starter, but there is no reason yeast could not grow that much. Yes, it is good to keep your starter steps to a manageable size.

[thatguy314]

The mr. malty calc has a couple of built in limitations. First is that it will not recommend more than 6 'yeast packages' worth of growth. The reason for this is that you want to ensure that the starter finishes quickly so that you don't end up growing other bugs or yeast instead of the yeast you are trying to grow.

That is completely wrong. The reality is that there is a limit to how much growth you are going to get in starters. You're not going to get unlimited growth. At a certain point you are just fermenting and making beer, not growing more yeast. The calculator takes this into account and doesn't let you waste starter wort for zero additional cells.

It would be better to ask than to just assume stuff that isn't correct.

Why are you attributing that to me? You're making it look like I had 2 pot shots in a row At least if you're going edit out what I said you could edit out my name.

Are you sure you meant 10 doublings? Biomass, even on an industrial scale, typically does not increase by 20 billion times in a single step. I'm quite certain I did not mean that. That's growing 1 cell to 20 billion cells, and I've never heard of anybody propigating anything to that degree without multiple steps. It's possible It's not efficient with time or resources.

As far making steps as big as you want, I will have to respectfully disagree. Just because yeast CAN grow does not mean that they will maintain their properties. 10x was supposed to be 100x, and it has to do with steps by which you grow a starter. Yeast can sense how many buddies they have around and perform differently depending on the situation.That was a rule of thumb I was taught when culturing microflora and mamalian cell culture to keep the population genetically homgenous. As I'm sure you're aware, they start expressing stress genes when they're made too dilute. When they start expressing stress genes they don't turn them off necessarily easily. It's always a good rule of thumb to keep microflora within 100x their original concentration. This doesn't necessarily mean that they'll mutate. It's like identical twins. One can be fat and one can be muscular. They both have the same genes (they haven't mutated) they're just expressing them to produce two very different results. While I haven't tested this as far as fermentation properties, I have noticed this effect in bacterial competent cells and mamalian cell lines. I find it mainly to be due to quorum signalling / cytokine signalling (as if you add cytokines, etc., it keeps them much happier and less stressed). The production of these signalling molecules is very much how they communicate their relative concentration to each other. I also find these organisms don't tend to grow very well/quickly if they haven't reached a certain critical concentration. I'd be hard-pressed to surmise that yeast cells didn't maintain the same properties that are shared with bacteria and other eukaryotic cell lines. That said,I'd be happy to be proven wrong. But I don't see it very likely that yeast deviate so much from so many other cultured organisms.

[jamilz]

If what you are saying was true, then the yeast grown when you ferment beer would not be any good. That is not the case. Again, you can grow yeast in as large a volume of starter you want. The resulting yeast is the same, you're just wasting wort or making beer.

[thatguy314]

If what you are saying was true, then the yeast grown when you ferment beer would not be any good. That is not the case. Again, you can grow yeast in as large a volume of starter you want. The resulting yeast is the same, you're just wasting wort or making beer.

You've said yourself that yeast that have undergone a beer fermentation behave differently than yeast grown in a starter, even multiple starters. Wouldn't that support my point, that yeast grown very dilute would behave differently, not refute it? I mean, a low gravity beer iused to build up yeast is just a dilute, reasonably hopped starter. Why do the yeast perform so much differently after that?