Advice on reusing yeast for a 2nd batch?

[LloydGM]

I've been reading (too much, I think) about reusing yeast for a 2nd (or more) batch of the same lager. I'm new at this, so could use a bit of advice from y'all experts.

My plan (is it viable?):

1. Brew Marzen batch #1, recover yeast & trudge from primary, wash*, store the yeast until bottling day
2. When bottling from secondary fermenter, repeat step 1 with new trudge
3. Combine yeast recycled from #1 & #2
4. Start batch #2 with recycled yeast.

Questions:
1. What's the cell count going into batch #2? Same as when starting batch #1?
2. Did the yeast from batch #1 multiply, giving me more cells for batch #2 as if the batch acted like some "yeast starter on steroids"?
3. Would I need to do a 2nd yeast starter with the yeast recovered from batch #1?

* From what I can tell, this means add sterile water, swoosh it, let settle, pour into 2nd container, repeat until little/no trudge is left.

 

[Jeremydc]

Tagging to learn this process as well. I’d also like to know how to estimate yeast count and how to know how much harvested yeast to use in the next batch/starter for next batch

 

[GoeHaarden]

My plan (is it viable?):

That would work fine, but IMO it's too much work...

When you transfer into your lagering vessel, assuming this is your reason for a secondary, you can swirl the yeast/trub up with a little bit of beer left in the primary. Collect that into sanitized mason jars, and store in the fridge. Then pitch one mason jar into the next batch. You could do a starter if you like for peace of mind, but I've had success with and without...

As to your cell count numbers, I have no idea...lol

 

[Shackleford_rusty]

That would work fine, but IMO it's too much work...

When you transfer into your lagering vessel, assuming this is your reason for a secondary, you can swirl the yeast/trub up with a little bit of beer left in the primary. Collect that into sanitized mason jars, and store in the fridge. Then pitch one mason jar into the next batch. You could do a starter if you like for peace of mind, but I've had success with and without...

As to your cell count numbers, I have no idea...lol

Ive done this process for years
Washing is too much work, and room for error is high.
Cell count i have no idea as well

 

[Qhrumphf]

Skip harvesting the secondary yeast. That's gonna be all low flocculating stuff. You'll get the best yeast after a soft crash and from the sort of middle of the cake. But isolating that is difficult without a conical.

As far as washing, depends on how clean it is. If you're good at separating out kettle trub it should be pretty clean and beer is better for the health of it than water. In which case leave a little beer behind, swirl it up and you're good.

If there's a lot of trub in there, yeah, you probably want to try and rinse it out.

Amount-wise (after discarding cold break and dirty yeast, and stopping before it gets thin, again tough to do without a conical), I typically plan on a 2-4x increase for lagers or 4-8x for ales (normal gravity). In other words 5 gals of Pils I'd expect to yield enough yeast for 10 gals (conservatively, potentially enough for 20 gals). If you're pitching into a higher gravity beer you'll need more. Strong lagers or super-high gravity ales (say, going from a Helles to Doppelbock or Bitter to a really big Barleywine) I might pitch the whole thing, but otherwise that's gonna be too way much yeast, which can cause its own off flavors.

Of course I'll adjust based on what I'm brewing and how much yeast I actually get.

 

[Qhrumphf]

The Mr. Malty calculator has slurry cell count estimates. If you're washing with water it's gonna be thinner, and if it's not really clean it's gonna be less cells per volume.

It'll also degrade quickly.

I typically pitch within a day or two of harvest and harvest thick clean yeast. I have washed slurry and stored it, and with that, yeah I'd make a starter, crash it out, and then try to estimate that cell count based on slurry.

Otherwise, you're gonna need a microscope and hemocytometer. That's the best way. Count it.

 

[hottpeper13]

It's better for the yeast to leave it on beer instead of water. So I look at the cake (clear fermenters) If there is a lot of junk under the yeast layer I leave more behind after racking so I get a real thin slurry. Pour that all into a 2 qt mason jar and let it settle out for 10 - 30 min, you'll see the junk layer forms first ,when it looks good to you transfer into 4 containers of equal amounts. I have a microscope and that is the only way to know cell counts for sure. So I found that a 5 gal batch of 1.040 - 1.060 yields enough yeast for 4 more 5 gal ferments. I have found that most yeasts have a more vigorous fermentation if used within 2 weeks, so I use 1 qt jars to store it so if it goes longer then 2 weeks I can steal a qt from the boil, chill it and make a vitality starter. Most of my beers take off in 4 hours or so.

 

[Conehead]

I just washed my lager yeast yesterday. I have 7 qt jars which look like around 10 ml at the bottom of each jar. 70 billion cells? I have no idea.

 

[LloydGM]

Holy moly, from what you guys are saying, it seems a 5gal batch of 50 point ale would yield up to 4x the original amount of yeast cells that what was originally pitched? Maybe 2x for lagers?

I've not figured out how to read the various calculators yet...still plenty of reading to do first, I think. My basic brews are med-heavy ales and med lagers, and from what I've learned so far, it seems like I'd be looking at counts of around 2 - 2.5 billion for my ales, around 5 billion for my lagers. That's just a semi-educated guesstimate so far, though, as I'm still trying to correlate the info I'm getting from various sites where hardly any 2 say the same thing, lol.

Oddly, I've made 13 batches of beer so far, all with 1 pack of Wyeast (3 lagers, 10 ales, 1 was a tripel). Some started fermenting a tad slowly, but all of them picked up steam and finished fermenting normally, lagers taking almost a week. I've read that fermenting too slowly won't yield the best taste, though, so I'd like to figure out how to do batches perfectly and consistently. I don't mind the extra effort up front as long as the end results are what I'm aiming towards. So I won't mind doing however much play (not work) it takes to get yeast cell counts high enough--but hopefully not TOO high. Problem I'm still having is trying to determine how much the yeast multiplies in a starter. I'm not afraid to experiment, either. I'm good at following the scientific principle, but it'd be best to start out armed with as much knowledge as I can.

I'll keep reading and listening to your guys' advice, so thank you so far and here's to as much as you guys can throw my way. /cheer

Oh, and as for cleaning, leaving the yeast in beer (vs. water) is great advice. If I can draw off most of a starter's beer, separate the yeast from the junk, then put the yeast back into the beer to store it for a day or 2 when I start the next batch, I think that'd work. I'm also thinking of a way I can get the yeast, junk, and beer to separate a bit and then use a suction probe to pull out just the junk...not sure if it'd work, I'd think it depends on how well I can get the yeast to separate...still thinking, though.

 

[twd000]

That would work fine, but IMO it's too much work...

When you transfer into your lagering vessel, assuming this is your reason for a secondary, you can swirl the yeast/trub up with a little bit of beer left in the primary. Collect that into sanitized mason jars, and store in the fridge. Then pitch one mason jar into the next batch. You could do a starter if you like for peace of mind, but I've had success with and without...

As to your cell count numbers, I have no idea...lol

quart-sized mason jars, or smaller pints? I repitched about 2 cups of Nottingham slurry into my porter two weeks ago, and it took off like a rocket

 

[GoeHaarden]

quart-sized mason jars, or smaller pints? I repitched about 2 cups of Nottingham slurry into my porter two weeks ago, and it took off like a rocket

I use the smaller pint jars.

Yeah, I love me some Nottingham at 60F. It's a beast and my brews consistently hit 1.010-12 FG with it. I'll harvest it occasionally but I like to cycle out my packet reserve...

 

[Calder]

Holy moly, from what you guys are saying, it seems a 5gal batch of 50 point ale would yield up to 4x the original amount of yeast cells that what was originally pitched? Maybe 2x for lagers?

Actually the resulting yeast is roughly 6X the 'ideal' cell count. However, some will already be dead, and some will die just being stored in the fridge. If used within a month of harvesting, pitch somewhere between a third and a half of the slurry you harvested.

If you want 'clean' slurry, you can pour the wort from the kettle through a mesh bag. I use a 5 gallon paint straining bag (washable/reusable). If using a bucket fermenter, you can tie a sanitized bag around the rim. I have a large funnel that I line with it. Just remove the bag after the wort is in the fermenter and before pitching yeast.

If you have 'clean' slurry, there really is no need to wash it if you use it within a month.

I usually don't need to add water to the fermenter to get he yeast out. Just swirl it around for a while and it becomes 'liquid' that can pour. However, after not needing to add any water for several years, I had to on my last batch as I guess I'd gotten almost all the beer out. I poured a few ozs of previously boiled water from my kettle.

As noted, only use the yeast from the primary. I always rack to add dry hops or gelatin, or other flavorings. Racking allows me to get the yeast before I add anything to the fermented beer.

Provided you sanitize everything that comes in contact with the yeast, you can continue to use the same yeast for several batches (Commercial brewers do). 5 is the recommended number of re-uses supposedly before mutations start to become noticeable, but since we are not brewing the same beer and trying to maintain consistency, we can get away with more ..... if you don't get bored with that yeast. I have done multiple generations in the past, but I now keep a number of yeasts in rotation, that I only re-use yeast once, twice, and occasionally 3 times before retiring it and then going back to the original starter.

 

[danielthemaniel]

From my research and experience here is my process. When you go to secondary or keg your beer leave just enough beer to cover the yeast cake. It helps if you cold crash before transferring your beer. Swirl the beer and yeast slurry then pour into sanitized mason jars. Make sure to use Mason jars that have mL listed on the side of the jar. This is because each mL contains between 1-3 billion yeast cells. The thicker the slurry, the closer to 3b/mL you have. It's an estimate but I typically estimate 1.5b per mL of slurry. One batch of beer will yield several times the amount of yeast you started with. It's worth noting the that you're 2-5ish time of repitching will yield a higher attenuation and quicker fermentation that your first use of the yeast. After the 5th time you will start to see degradation. Once you get make a beer that lacks yeast character or isnt performing up to standards its time to get a fresh vial of yeast.