Yeast cells estimate from volume

How would I estimate how many yeast cells are in X cubic inches of settled yeast (like from yeast washing)? I know how to determine the volume, (pi * r ^2 * H) just not sure what to do from there.

Get a microscope, a hemocytometer, and a graduated cylinder and dilute the yeast and count the cells. You don't need a particularly strong microscope, you can probably pick up one used online.

gio said:

Get a microscope, a hemocytometer, and a graduated cylinder and dilute the yeast and count the cells. You don't need a particularly strong microscope, you can probably pick up one used online.

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That seems very cool I must get a hemocytometer - and a lab coat to go with it!

Is there no "average" you could use for a rough guesstimate?

http://www.wyeastlab.com/com-yeast-harvest.cfm

"Generally 40-60% yeast solids will correlate to 1.2 billion cells per ml. This will very with the yeast strain. "

Wyrmwood said:

That seems very cool Is there no "average" you could use for a rough guesstimate?

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How compacted is your yeast cake?

This is why there's no "average".

I was curious about how much yeast I was collecting after a wash also. Just guessing I usually have about a 1/4 cup of yeast solids in each pint jar after washing. This is pretty clean stuff so I would say that it surely meets the 40%-60% that Wyeast talks about here; http://www.wyeastlab.com/com-yeast-harvest.cfm

So 1/4 cup is about 60ml. 1.2 billion cells per ml. 60 x 1.2 billion = 72 billion.**

72 billion cells is a little short of a smack pack but plenty to do a 1 liter starter imho.



Correction
** I went back to Wyeast and looked at the info about harvesting yeast. It seems I'm measuring the yeast solids from the slurry. It's not 40% or 60% yeast solids from slurry, it's more like 100% yeast solids.

So I suppose that if 50% slurry gets you around 1.2 billion cells, then 100% solids should get you around 2.4 billion cells per ml of solids?

1/4 cup of solids is 60ml. 2.4 billion cells per ml. 60 x 2.4 billion = 144 billion cells!


Anyone else figure it like I am?

So, for each cubic inch, that's about 16ml and in my pint jars, about 8 cubic inches per inch of sediment. Most of mine are 1/8 to 1/4 inch, so between 1 and 2 cubic inches or between 16 and 32ml, or around 60 billion cells on average in a jar, say 50 to account for the slightly rounded end. So, for my next high gravity beer, brewtarget tells me I need 325 billion cells for 5 gallons at 1.096, or about 6 jars? Or should I just use a three or four jars and make a starter? (I have 8 jars.) I guess I should do the starter in any case, to ensure viability, but then how much do I need (or wait/keep adding until I have 300 billion in the starter?)

I respect the quest for knowledge, but I am glad that I do not take yeast counting so seriously.

Think ancient germans had a hemocytometer? Me either.

Methinks my best guess will be as accurate as your extrapolated hemocytometer findings, and will take 1/100000000 of the time and effort.

To each their own though.

cheezydemon3 said:

I respect the quest for knowledge, but I am glad that I do not take yeast counting so seriously.

Think ancient germans had a hemocytometer? Me either.

Methinks my best guess will be as accurate as your extrapolated hemocytometer findings, and will take 1/100000000 of the time and effort.

To each their own though.

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Care to give it a wag?

Lol, How would we know?

I am just saying, batch for batch, even if you are 12% more accurate, will it make any measureable diff in the beer?

I doubt it. It's probably even less possible to measure that.

Wyrmwood said:

So, for each cubic inch, that's about 16ml and in my pint jars, about 8 cubic inches per inch of sediment. Most of mine are 1/8 to 1/4 inch, so between 1 and 2 cubic inches or between 16 and 32ml, or around 60 billion cells on average in a jar, say 50 to account for the slightly rounded end. So, for my next high gravity beer, brewtarget tells me I need 325 billion cells for 5 gallons at 1.096, or about 6 jars? Or should I just use a three or four jars and make a starter? (I have 8 jars.) I guess I should do the starter in any case, to ensure viability, but then how much do I need (or wait/keep adding until I have 300 billion in the starter?)

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Take one of your empty jars and add water to the same level as your yeast, then measure that in something to be sure of the volume.

I would make a starter for sure. Mr Malty calculator says that you would need two packs of liquid yeast in a 1.4L starter for your batch, with intermittent shaking of the flask. Or 1 liter on a stir plate. Each pack is has about 100 billion cells.

So if you get 60 billion or so out of your jars, I would dump in 3 or 4 and make a nice starter. The yeast viability should also be considered but if it's not very long in the jars I wouldn't worry about it.

cheezydemon3 said:

I respect the quest for knowledge, but I am glad that I do not take yeast counting so seriously.

Think ancient germans had a hemocytometer? Me either.

Methinks my best guess will be as accurate as your extrapolated hemocytometer findings, and will take 1/100000000 of the time and effort.

To each their own though.

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I don't want to poop on your methods (and I certainly am not about to suggest that you go out and buy a hemocytometer if you aren't interested in one) but I rather routinely see about a four-fold variation in cell counts from an equivalent volume. That means that any volume-based estimation could be anywhere from half of to double the real number. You may or may not find that difference particularly important; we all have a different sense of what should be controlled in brewing and to what extent it matters. I find it to be significant, though.

The ancient Germans did not have hemocytometers, but the modern ones sure as heck do. The old European brewers didn't even know about the existence of yeast; they only reason the were able to successfully brew was that their sanitation was also so bad that yeast propagated from one batch to the next. All speculation seems to be that pre-modern beer was inconsistent and sour.

Like I said, I don't think you need a hemocytometer to make good beer, but it's also incorrect to say that volume measurements are just as accurate. I know a guy who doesn't even own a scale and just chucks grain into his mash tun until it looks about right to him. His beers are good, but completely unreproducible.

In any case, brew on brotherman!

@Wyrmwood: +1 on making a starter. Even if you can harvest an appropriate pitching quantity of yeast, a starter will give that yeast a chance to rebuild glycogen, trehalose, and enzymes.

cheezydemonmalfet

I do look at the density of the cake and take that into account, but I am probably more akin to your friend, interested in making good beer, not necessarilly reproducing it exactly again and again.

cheezydemon3 said:

cheezydemonmalfet

I do look at the density of the cake and take that into account, but I am probably more akin to your friend, interested in making good beer, not necessarilly reproducing it exactly again and again.

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...and that's totally legit. I'd probably be better off in all domains of my life if I were slightly less OCD, but that very OCD trait compelled me to warn my OCD bretheren on this board (we are legion) that volume measurements do not meet or exceed national OCD requirements.

And all the more valuable info to us bretheren of the eyeball!

May your years be many and pleasant upon this earth good sir.

MalFet said:

The old European brewers didn't even know about the existence of yeast; they only reason the were able to successfully brew was that their sanitation was also so bad that yeast propagated from one batch to the next.

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I have read that "Brewers generally took some sediment from the previous fermentation and added it to the next, the sediment generally containing the necessary organisms to perform fermentation. If none were available, they would set up a number of vats, relying on natural yeast to inoculate the brew." (http://en.wikipedia.org/wiki/Reinheitsgebot) Interesting that they while they did not "know" of yeast until Pasteur, they certainly understood it's usage and necessity.

Wyrmwood said:

I have read that "Brewers generally took some sediment from the previous fermentation and added it to the next, the sediment generally containing the necessary organisms to perform fermentation. If none were available, they would set up a number of vats, relying on natural yeast to inoculate the brew." (http://en.wikipedia.org/wiki/Reinheitsgebot) Interesting that they while they did not "know" of yeast until Pasteur, they certainly understood it's usage and necessity.

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Yeah, it's interesting stuff, but we're conflating a lot of different eras in history here. In the early modern period, people certainly know about the importance of yeast before they know it was "yeast". In some traditions, it was called just "godisgood". Earlier than that, though, the Vikings had heirloom wooden sticks that they used to stir the beer. They imagine that it was the sticks causing the fermentation, rather than all of the gunk that was living in the wood.

In a lot of South Asia, people make something akin to beer via perpetual fermentation in a never-cleaned wooden barrel. Whenever they take some fermented grain out from the bottom, they add a bit more fresh stuff to the top. Anyway, sorry to derail. If you have any further questions dont hesitate to force this thread back on track.