First time re-using yeast

[Joe.Conley]

It was my first time re-using yeast, this weekend. (lined up 3 or 4 recipes using the same yeast so I thought I'd give it a try). I had no way to count the yeast so I used the most conservative number on this thread in the forum, and used all ~6 oz (assuming 30 billion cells per fl oz, so 180 billion cells to hopefully grow to 350 or 400 needed for the recipe) of slurry in this jar, I think it was way too much.

(right jar was harvested first, but I assume it was more dead yeast, so I used the second one. Maybe next time I should take 3 small jars and just use the 2nd jar to get the healthiest yeast that aren't dead or too flocculent)

It was two weeks between harvesting and pitching, and it was my first time re-pitching so I did a starter just to make sure it was viable. I tried to get away with 1.8L starter in the 2.5L flask but I think it was way too much yeast because after little foam on the stir plate for 18hrs it foamed out the top, and never stopped bubbling up CO2 after 18 hours on the counter with no stirring, and 8+ hours in the fridge (same procedure I've been using with packet yeast, with times a little shorter or longer based on growth factor). I had to decant good yeast that never settled, but there looked to be more than enough settled on the bottom of the starter, though weirdly there were 3 or 4 visible layers of stratification on the bottom, which was strange since the source jar looked quite uniform. The lag time was longer this time, about a whole day versus 10 or 12 hours when I used the same Wyeast 1056 from the package, and the starter as well as the fermentor smell(ed) more fruity (in addition to yeasty) that I would expect, maybe touching on a sour note. Hope there's not an infection

. The fermentation is going strong now at least.

Anyone have similar experiences, or tips on how to improve the process? Thinking about getting a microscope, I hear there's a software that can count cells for you if you get a digital image.

 

[kmarkstevens]

Holy moly, I am no expert on yeast counts, but the jar on the left is a giant pitch. Not as much as on top of a yeast cake, but probably 5 if not 10 times a WLP starter. No need to have put that in a starter.

The one on the right looks to be plenty for a healthy 5 gallon batch. Honestly, it's more volume and fresher than what you would get from one of the major yeast houses.

To explain further, I've been using stir plates to build up starters, and then saving in either 4oz canning jar or just a 100ml centrifugal tube. I have pitched many a 5 gallon 1030-1040 OG brew with a centrifugal tube 1/4 full of packed yeast and 3/4 full of liquid.

I recently bought the fermentasaurus 3 gallon centrifical to make half batches and harvest the yeast. I find this yields about 8oz of yeast in a 1030-1040 OG beer. Maybe the bottom 2 oz is not so clean but you can discard that.

Typically, when I get a liquid yeast from one of the major brands. I usually pitch about 3/4 and then use 1/4 to stir plate up 2 liters. I decant the stir plate, save in 4-5 centrifugal tubes and/or 4 oz canning jar. Then I use one of the centrifugal tubes to pitch and or make starters for a few generations. Then I start over. One mother batch of yeast can easily do 20 different pitches this way. I haven't had infection issues to date.

 

[IslandLizard]

Anyone have similar experiences, or tips on how to improve the process? Thinking about getting a microscope, I hear there's a software that can count cells for you if you get a digital image.

I'm still chewing on your post...

To reduce foaming while boiling and also during propagation, use one drop of Fermcap-S per gallon (or partial gallon) of starter wort. Store the fermcap in the fridge, it should last for many years. Before use, shake the vial well. No, shake it very well, it's thick, syrupy, you want to homogenize it. Depending on the vial you get, you may need to unplug the little flip spout with a toothpick before you can gently squeeze out that single drop.

Be aware when growing/propagating yeast there's a limitation to how much a culture can grow. The 1st factor is inoculation rate, the 2nd is wort volume (and of course, starter gravity, but there are limits on that too).

Here are my 2 favorite yeast pitch/propagation calculators I use:
BrewUnited's Yeast Calculator - For 90-95% of all yeast calcs/starters I do.
Mr. Malty - Especially the "pitching from slurry" tab is unique for estimating yeast/trub percentage in saved slurries.

When you see 3 layers - trub/dead yeast is always on the bottom. The least flocculent yeast precipitates last, on top. And a mixed yeast/trub layer in between. Mind, even the trubby bottom layer can contain anywhere between 20-80% yeast, so you may want to use (some of) that too if it's in the higher %.

Yeast counting is a real chore. Aside from a decent microscope, you'd also need a hemocytometer and a way to dilute your yeast culture a few times rather accurately. Then after counting, you multiply the counted result with your dilution factor and voila!

There are a few sites that will give you a good taste of what's involved in the process. You may decide not to bother, I don't anymore. I estimate and make healthy starters. You get good at estimating after a few times, using BrewUnited's calc.

There's plenty to learn for yeast harvesting and making yeast starters, here, so look around, also some of the later threads.

 

[Joe.Conley]

Holy moly, I am no expert on yeast counts, but the jar on the left is a giant pitch. Not as much as on top of a yeast cake, but probably 5 if not 10 times a WLP starter. No need to have put that in a starter.

Ha, thanks for confirming my suspicions

Typically, when I get a liquid yeast from one of the major brands. I usually pitch about 3/4 and then use 1/4 to stir plate up 2 liters. I decant the stir plate, save in 4-5 centrifugal tubes and/or 4 oz canning jar. Then I use one of the centrifugal tubes to pitch and or make starters for a few generations. Then I start over. One mother batch of yeast can easily do 20 different pitches this way. I haven't had infection issues to date.

Curious about this centrifuge setup, sounds expensive but intriguing...

 

[Joe.Conley]

To reduce foaming while boiling and also during propagation, use one drop of Fermcap-S per gallon (or partial gallon) of starter wort. Store the fermcap in the fridge, it should last for many years. Before use, shake the vial well. No, shake it very well, it's thick, syrupy, you want to homogenize it. Depending on the vial you get, you may need to unplug the little flip spout with a toothpick before you can gently squeeze out that single drop.

Oh I have that and used it in the starter boil, but did not shake it or add any more to the starter after the boil. I wasn’t aware of the refrigeration requirement either, I think it was just on the shelf at the home brew store and the label doesn’t say much.

Here are my 2 favorite yeast pitch/propagation calculators I use:
BrewUnited's Yeast Calculator - For 90-95% of all yeast calcs/starters I do.
Mr. Malty - Especially the "pitching from slurry" tab is unique for estimating yeast/trub percentage in saved slurries.

I’ve been wanting to use the mr malty one, but it seems to be Adobe flash, which has breathed it’s last breath in 2020, and no browsers support it anymore since it’s a huge security nightmare

Yeast counting is a real chore. Aside from a decent microscope, you'd also need a hemocytometer and a way to dilute your yeast culture a few times rather accurately. Then after counting, you multiply the counted result with your dilution factor and voila!

Haven’t thought about the diluting process, sounds easy to mess up.

 

[IslandLizard]

Oh I have that and used it in the starter boil, but did not shake it or add any more to the starter after the boil. I wasn’t aware of the refrigeration requirement either, I think it was just on the shelf at the home brew store and the label doesn’t say much.

If it doesn't quite live up to its promise, you can always use 2 drops... or 3. One drop works fine here after good shaking.
I don't know how sanitary the Fermcap is, so I never add it to cold wort or beer.
I guess you could boil it in a little water in the microwave, then add that.

I’ve been wanting to use the mr malty one, but it seems to be Adobe flash, which has breathed it’s last breath in 2020, and no browsers support it anymore since it’s a huge security nightmare

That's a sad problem waiting to happen, yes. I hope a solution will be found or offered by then.

Haven’t thought about the diluting process, sounds easy to mess up.

It has a bit of a learning curve, yes, but the actual counting can be truly cumbersome. You're also not counting them all, only a certain fraction, depending on method used.

 

[kmarkstevens]

Curious about this centrifuge setup, sounds expensive but intriguing...

Long story short, it's a plastic sterile test tube: SPL 50ml Conical Centrifuge Tube PP/HDPE with PP Racks, Sterile, Non - pyrogenic, Non - cytotoxic, DNase/RNase - Free, Human DNA - Free (1 Rack (25 Tubes)): Amazon.com: Industrial & Scientific

First time, just pour in your yeast. The second use you have to sterilize it in an instant pot or pressure cooker.

Also, make sure there is at least 10cc liquid. I found if it is all thick yeast slurry it expands and leaks. A bit of liquid buffer works just fine.

 

[Calder]

I'm sure a lot of yeast purists will cringe at this, but I have tried the yeast counting, and yeast washing and starters with slurry, and after several years (maybe decades at this point), I have come to the conclusion that it is all just a guess and washing and starters are just more potential opportunities for contamination.

Every beer I make I filter the wort going into the fermenter (use a paint straining bag), to minimize crap in the slurry. If I am going to add anything to fermentation, I rack to secondary to allow me to harvest clean yeast (yes, I know there are potential issues with racking, but I have not experienced any). I just swirl the remaining sludge in the fermenter (no added water), and pour into sanitized mason jars and store in fridge until required.

If I brew within a month, I use 1/3rd of the slurry. If it is 2 months I use half the slurry, and if 3 months or more .......... after deciding I don't have other yeast I would prefer to use, I will use all of the slurry.

Per 'Yeast' Zainasheff and White, a fermentation will produce 6X the required cells for a 'perfect' pitch. Assuming some lost in the fermentor and storage, I figure a third of the slurry is about right to pitch into a beer of similar gravity.

No washing for storage, and not starter before pitching. Has been working well for several years.

I have recently started washing the yeast prior to brewing, to minimize the amount of dead yeast going into the fermenter. Not sure it is worth it, as dead yeast is food/nutrients for the yeast.

 

[kmarkstevens]

On Black Friday, Austin Homebrew had the Genesis Fermenter Sanitary bag for $0.12 each. It might have been a mispriced typo and is now $1.00 each (this is a close out and dumping all their inventory for Genesis). Anyhoo, I bought a bunch of these thinking that I'll do a 1030-1050 OG beer, rack off to the keg, let the remainder settle, cut a small hole in the bottom for the sludge to drain out, and then drain out the remaining "clean" yeast into canning jars. This should yield multiple 4oz canning jars full of good yeast slurry.

In my experience, a 4oz canning jar 1/2 - 3/4 full of slurry results in a strong fermentation starting within a few hours even after having been stored in the fridge for "a few months or so."

@Joe.Conley I bet your 6oz jar could have easily kicked off 2-3 strong pitches for 5 gallon batches

 

[IslandLizard]

On Black Friday, Austin Homebrew had the Genesis Fermenter Sanitary bag for $0.12 each. It might have been a mispriced typo and is now $1.00 each (this is a close out and dumping all their inventory for Genesis). Anyhoo, I bought a bunch of these thinking that I'll do a 1030-1050 OG beer, rack off to the keg, let the remainder settle, cut a small hole in the bottom for the sludge to drain out, and then drain out the remaining "clean" yeast into canning jars. This should yield multiple 4oz canning jars full of good yeast slurry. [...]

The Genesis Bioreactor!