Why Not to Pitch On Your Yeast Cake

[Denny]

I see. That requires a lot of planning

So you just don't want to reuse the yeast from a really big beer. Like > 1.070? Would you reuse that?

If the 1.070 beer seemed to have a good fermentation, I'd take a chance on reusing it....probably. Depends on if I'm feeling lucky!

 

[TrubHead]

Quite interesting reading this thread although I did skip the middle pages of "discussion". Think I'll stick with washing the yeast vs pitching wort onto yeast cake.

Sampled another home brewer's beer a while back and told him it tasted a little soapy. Could pitching onto trub/yeast cake cause this?

 

[Darwin18]

Quite interesting reading this thread although I did skip the middle pages of "discussion". Think I'll stick with washing the yeast vs pitching wort onto yeast cake.

Sampled another home brewer's beer a while back and told him it tasted a little soapy. Could pitching onto trub/yeast cake cause this?

More likely attributed to his cleaning/sanitizing methods.

 

[Brewskii]

So if you pitch a copious amount of yeast (either from a cake or starter), should you then be causing an over pitch scenario by oxigenating that wort at pitch?

I gather the esters are produced in this lag phase during o2 take-up....- is that right?

 

[cheezydemon3]

I don't think anyone is endorsing pitching on the whole cake (unless it is bred specifically for a HUGE beer or big lager). Overpitching can be a problem.

I Use sanitary water to rins all but about 2 cups of the yeast cake out of the fermenter. Wipe the lip and inside of fermenter with NO RINSE soaked paper towel.

Dump chiled wort on remaining yeast.


Rinse and repeat!

 

[TubaHooah]

I recently brewed my first all grain (a Rye/Biscuit Ale) using a batch sparge. After collecting my boiling amount I was intrigued by the still somewhat sugary grains left in my Mash Tun. I decided to do an experiment and collected a 1 gallon cold sparge, boiled for about 45 minutes with a fraction of the hops from my recipe, and pitched with about a half packet of US-05 in a 1 gallon carboy. I got a pretty vigorous fermentation and I'm excited to try my "small beer," but this thread has me thinking that I may be able to use the yeast cake from the 1 gallon batch to ferment a new 5 gallon batch. The ratio may be not quite right, but it's more than pitching just 1 vial of liquid yeast.

Any thoughts?

 

[grndslm]

I recently brewed my first all grain (a Rye/Biscuit Ale) using a batch sparge. After collecting my boiling amount I was intrigued by the still somewhat sugary grains left in my Mash Tun. I decided to do an experiment and collected a 1 gallon cold sparge, boiled for about 45 minutes with a fraction of the hops from my recipe, and pitched with about a half packet of US-05 in a 1 gallon carboy. I got a pretty vigorous fermentation and I'm excited to try my "small beer," but this thread has me thinking that I may be able to use the yeast cake from the 1 gallon batch to ferment a new 5 gallon batch. The ratio may be not quite right, but it's more than pitching just 1 vial of liquid yeast.

Any thoughts?

Sure....

Rinse the yeast cake.... https://www.homebrewtalk.com/f163/yeast-washing-illustrated-revisited-318684/

 

[BigFloyd]

I got a pretty vigorous fermentation and I'm excited to try my "small beer," but this thread has me thinking that I may be able to use the yeast cake from the 1 gallon batch to ferment a new 5 gallon batch. The ratio may be not quite right, but it's more than pitching just 1 vial of liquid yeast.

Any thoughts?

Actually, that 1 gallon cake ought to be pretty darn close for a 5 gallon batch. You're much better off maybe slightly over-pitching with that vs. using one vial of liquid yeast with no starter (which is a significant under-pitch)

Unless the 1 gallon batch has a bunch of trub/hops, I'd harvest it into a sanitized jar and pitch the whole thing straight onto the 5 gallon batch. If you're going to wait any more than a few days before use, rinse it.

 

[jwalker1140]

Sure....

Rinse the yeast cake.... https://www.homebrewtalk.com/f163/yeast-washing-illustrated-revisited-318684/

Or if you intend to repitch the yeast within a week or two, just follow the technique outlined by the OP and save yourself some trouble.

 

[grndslm]

Or if you intend to repitch the yeast within a week or two, just follow the technique outlined by the OP and save yourself some trouble.

Where's the trouble in rinsing??

Boiling is trouble???

Boil one pot of water with your jar(s) for 5 minutes. Take the bottles out with tongs, screw on lids, put in freezer. Throw that water into the carboy, bucket, or whatever other fermenter you've got.... swirl around, set it at angle so that the trub falls into a corner and will stay there when you get ready to pour the CLEAN yeast out. Leave it for 30 minutes, then pour the liquid into the jars.

We're talking an hour and a half to separate from the trub (hops, dead yeast, etc.). And you can pitch one of those jars immediately if you'd like. No need for the top liquid to become totally clear.

I think what the OP tries to accomplish is estimating how much yeast there is WITHIN the trub. But he thinks calculating yeast count is of the utmost importance???

ipe:

Uhh... yea.... let's calculate our good yeast without separating from the dead yeast, hops, and other trash.

Good one.

 

[jwalker1140]

Apparently the word "trouble" bothers you. That's fine. Replace it with "extra time and effort." 90 minutes (by your estimate) to rinse, including an extra transfer, vs. 30 seconds to pour some slurry into a sanitized mason jar.

Now, I'm perfectly willing to put in extra time and effort if it offers a reasonable benefit. I assume you think rinsing does because, I'll paraphrase, "it lets the trub fall into a corner so you can pour the CLEAN yeast out." I would strongly suggest reading the work Steven Deeds has done on this topic here: http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

Among his more interesting findings is that the ratio of trub to viable yeast is the same throughout the rinsing container. Meaning, we're not really separating clean yeast from the trub by rinsing, we're just tossing most of it out. And that nasty trub we're so worried about, it's mostly protein that's actually beneficial to yeast as it aids in cell wall development, according to Fix. I was also surprised to learn that the top portion we try to collect contains a much higher level of bacteriological content, up to 100x more than in the bottom portion. So much for being cleaner....

Lastly, my takeaway from the OP was not that we all should do yeast counts or math, but rather the exact opposite since other more knowledgeable people (e.g., Fix, Daniels, Bamforth et al.) have already done that for us. Because of them, we can skate by with the simple rule-of-thumb that 1 cup of fresh slurry is enough for 5 gallons of 1.048 wort.

My reply probably sounds more snide or confrontational than I intend, and for that I apologize. I'm sure my tone would come across better if we were discussing over a couple pints. Heck, I'd even buy the next round.

 

[fosaisu]

I would strongly suggest reading the work Steven Deeds has done on this topic here: http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

Among his more interesting findings is that the ratio of trub to viable yeast is the same throughout the rinsing container. Meaning, we're not really separating clean yeast from the trub by rinsing, we're just tossing most of it out. And that nasty trub we're so worried about, it's mostly protein that's actually beneficial to yeast as it aids in cell wall development, according to Fix. I was also surprised to learn that the top portion we try to collect contains a much higher level of bacteriological content, up to 100x more than in the bottom portion. So much for being cleaner....

Lastly, my takeaway from the OP was not that we all should do yeast counts or math, but rather the exact opposite since other more knowledgeable people (e.g., Fix, Daniels, Bamforth et al.) have already done that for us. Because of them, we can skate by with the simple rule-of-thumb that 1 cup of fresh slurry is enough for 5 gallons of 1.048 wort.

Thanks for posting that very interesting link on yeast rinsing! Definitely worth a read for anyone that hasn't checked it out.

And I agree with your take on the OP's point -- he's saying that the research suggests you'll get better tasting beer using a cup of slurry (or two for a higher OG beer) instead of the whole yeast cake. No way to tell how many yeast cells are in a given cup of slurry without using a microscope, but it should at least be in or near the ball park of proper pitching rate, and much closer than an entire yeast cake which is virtually certain to contain way too many cells.

 

[cheezydemon3]

Not sure why, but I have done a complete reversal.

I get new yeast every time now.....I need to brew more often....

 

[Fordzilla]

Not sure why, but I have done a complete reversal.

I get new yeast every time now.....I need to brew more often....

Same thing happened to me. I stopped brewing as much and stopped reusing yeast.

 

[cheezydemon3]

Humph! Time to get back in!

 

[Fordzilla]

Especially since my 5 tap keezer is up and running. Gotta keep it stocked!

 

[grndslm]

Apparently the word "trouble" bothers you. That's fine. Replace it with "extra time and effort." 90 minutes (by your estimate) to rinse, including an extra transfer, vs. 30 seconds to pour some slurry into a sanitized mason jar.

Now, I'm perfectly willing to put in extra time and effort if it offers a reasonable benefit. I assume you think rinsing does because, I'll paraphrase, "it lets the trub fall into a corner so you can pour the CLEAN yeast out." I would strongly suggest reading the work Steven Deeds has done on this topic here: http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

Among his more interesting findings is that the ratio of trub to viable yeast is the same throughout the rinsing container. Meaning, we're not really separating clean yeast from the trub by rinsing, we're just tossing most of it out. And that nasty trub we're so worried about, it's mostly protein that's actually beneficial to yeast as it aids in cell wall development, according to Fix. I was also surprised to learn that the top portion we try to collect contains a much higher level of bacteriological content, up to 100x more than in the bottom portion. So much for being cleaner....

Lastly, my takeaway from the OP was not that we all should do yeast counts or math, but rather the exact opposite since other more knowledgeable people (e.g., Fix, Daniels, Bamforth et al.) have already done that for us. Because of them, we can skate by with the simple rule-of-thumb that 1 cup of fresh slurry is enough for 5 gallons of 1.048 wort.

My reply probably sounds more snide or confrontational than I intend, and for that I apologize. I'm sure my tone would come across better if we were discussing over a couple pints. Heck, I'd even buy the next round.

Let me just first say that that's an awesome post. But let me add my corrections first....

(1) There is 90 minutes of waiting. But maybe 180 seconds of actual work versus your claimed 30 seconds of actual work, which... if you're doing it properly... will still be sterilizing the jars by boiling them for 5 minutes, which means you're still going to be doing that full 180 seconds of actual work that yeast rinsing requires. The ONLY real time spent waiting is for the boiled water to cool && for the trub to fall to the bottom of the carboy. So we're talking 87 minutes of waiting is really what you're complaining about. There is NO EXTRA EFFORT, other than putting the boiled water & jars into the freezer. That is the ONLY bit of extra effort, as compared to the "save ALL the yeast cake" method. If that's what you consider to be trouble, then I can tell I wouldn't put you at the top of list of homebrewers that I'd be interested in tasting their beer (I don't have any list, but you get the idea. ).

(2) I will look at your link about yeast rinsing not completly removing the trub, but at the same time... I know that the author is not rinsing yeast properly if he is still getting trub in his first jar. By angling the carboy/fermenter so that the trub falls into a corner, waiting 30 minutes for the trub to fall to that corner, and using an auto-siphon... there will be ABSOLUTELY ZERO trub in your jars. That is yeast rinsing. I already know that whatever he did is the wrong way.

(3) The bit about throwing out the "nasty trub" actually being beneficial for the yeast is something that I hadn't really thought about... but when I think of "nasty trub" it is primarily hops that are not included in my next recipe. For example, my buddy and I got some yeast from an IPA from a local brewery. We only wanted to make a pale ale. What I consider a half-ass rinsing is to remove the trub from the completely new recipe, yet leave the "dirty water" in without pouring it off. A full rinsing would require *all* the yeast to drop (which takes a week or so) and leave clear liquid above. That would remove virtually every last possible ounce of old recipe from the new. But simply removing the hops is a bit better than not removing it at all, IMHO. Sure, the old, "nasty trub" is beneficial for the new recipe... but the new, "clean trub" is really what I'm after in my new recipe, and it's JUST as beneficial.

(4) I disagree that the OP thinks that yeast counting isn't important, as that's precisely what he's doing.... but he's doing it from a standpoint of a "rule-of-thumb" that's based on some generic recipe, which who knows what that is. The amount of hops changes with each recipe. The initial yeast count changes with each recipe. The various yeasts change their own final count with each recipe. It is virtually impossible for the homebrewer to do a yeast count, but it's far more accurate to spend the extra 5 seconds of work to put the boiled water into the freezer and the extra 87 minutes of waiting for the water to cool and the trub to fall in the carboy/fermenter.



But anyway.... I enjoyed your post and will read your link fully now. Just think that it is ZERO extra trouble to rinse the old trub, other than waiting. But "patience is a virtue" is an understatement when it comes to making good beer. And if yeast count is as important as the OP claims, an extra 87 minutes of waiting sure ain't gonna hurt and can only bring about the best consistency that any typical homebrewer is going to realize.

 

[grndslm]

OK.... so that is an interesting link, for sure, because the guy is actually using a microscope, apparently???

He is still not rinsing yeast properly, from what I can tell. To learn how to rinse properly, see the link I shared earlier, which is also in my signature. Pay particular attention to wolverinebrewer's posts, which I will link directly here ---> image && process to get that "100% yeast".

Steven Deeds, whose blog you linked to earlier, is again definitely not doing it right, as you can see from that pic on the top of the article. Something else that troubles me is that he mentions there being bacteria in the liquid. Where is that bacteria coming from?? Surely not his boiled water, right? That was bacteria that was already in the yeast cake. He's saying that it's a GOOD IDEA to remove that bacteria by pitching the liquid. Sure, but in my "half-ass rinsing" method I'm mentioning, there is no legitimate opportunity to dump the liquid within less than 3 days, otherwise you're dumping the least flocculant yeast, which you may want to keep around for as many generations as possible (even just the next one). Now that I'm thinkin about it, tho, in order to see a decent guesstimate on how much yeast you have with my half-ass method, you will need several hours, and preferably overnight to get a vague idea of how much yeast you have. But if done properly, you can at minimum, remove ALL the trub from the equation.

The last set of questions, initiated by CA Brewer in Jan. 2013, presents some information that I would think needs more elaboration. The very last sentence, in particular, "In my experience there is more protein from the wort than added when by the repitched slurry." is a sentence that I don't find incredibly legible. Is he agreeing with me that the new, "clean trub" provides the protein that we're really after, as opposed to the old, used, "nasty trub"? I think he is, no?

He has a newer post ( http://woodlandbrew.blogspot.com/2013/01/yeast-washing-revisited.html ) that I have yet to read, as well... but, again, from the picture... he's still not rinsing properly, because he's still seeing trub.

I read Yeast a year or so ago, but I don't remember exactly how you measure "viability". Perhaps someone can refresh my memory on how this is done??

 

[EarlyAmateurZymurgist]

Yeast washing is a completely unnecessary step that is more harmful than it is beneficial. Beer is a significantly more hostile environment to house microflora than boiled water. Boiling does not kill spores (water has to be autoclaved to kill spores), and most water supplies have a pH that is significantly higher than beer, which will allow the spores to germinate. The proper way to separate yeast from the trub is to leave enough fermented beer behind after racking to be able to swirl the viable yeast back into suspension. Dead yeast cells and the heaviest fractions will quickly settle out, leaving mostly healthy yeast in suspension. It is beneficial to the health of the culture bring a small amount of the protein fraction of the trub over with the yeast.

Commercial breweries only wash their yeast when they are performing an acid wash in an attempt to salvage a crop that is infected with house microflora. The pH of the solution that is used during acid washing is significantly lower than that of tap water.

 

[Denny]

Yeast washing is a completely unnecessary step that is more harmful than it is beneficial. Beer is a significantly more hostile environment to house microflora than boiled water. Boiling does not kill spores (water has to be autoclaved to kill spores), and most water supplies have a pH that is significantly higher than beer, which will allow the spores to germinate. The proper way to separate yeast from the trub is to leave enough fermented beer behind after racking to be able to swirl the viable yeast back into suspension. Dead yeast cells and the heaviest fractions will quickly settle out, leaving mostly healthy yeast in suspension. It is beneficial to the health of the culture bring a small amount of the protein fraction of trub over with the yeast.

Commercial breweries only wash their yeast when they are performing an acid wash in an attempt to salvage a crop that is infected with house microflora. The pH of the solution that is used during acid washing is significantly lower than that of tap water.

ALL OF THIS!!!!^^^^^

You can quote numbers and studies to me all day, but all I care about is the quality of my beer and the ease and fun of making it. I've rinsed yeast and I've saved and reused it without rinsing it. I saw no difference in performance or final beer quality. It took extra time and effort to do the rinsing, and I don't care to expend time and effort without a noticeably beneficial return. Yeast rinsing didn't give me that noticeably beneficial return and I quit doing it. My own experience is all the evidence I need.

 

[jwalker1140]

Grndslm, you'll have to forgive me for not taking the "time and effort" to offer a full point-by-point reply, but I would like to make a few comments.

I will agree that waiting 87 minutes may not be a big deal ... unless you want to go to bed, go to work, go to a movie, go out to dinner, etc....

I hit my mason jars with a few squirts of StarSan from a spray bottle. Quick and easy. You imply this isn't good enough when you write that boiling the bottles in water for 5 minutes is the proper method because it sterilizes them. We'll have to agree to disagree on this point. At the very least, you may want to research the difference between 'sterilizing' and 'sanitizing' before you make more posts on this topic.

You also seem convinced that Bernie Brewer's 'yeast washing illustrated' approach is the proper way to rinse yeast and that other methods, like the one Steven Deeds used, are wrong. Since you indicate that you've read "Yeast" by White and Zainasheff, you've realized they also do it wrong. How embarrassing. If you let them know, maybe they'll fix this in the 2nd edition.

I've used the 'yeast washing illustrated' technique many times. I've also used the OP's 'why not to pitch...' technique many times. I'm not here to evangelize for one technique over another, but I will say that, overall, I've experienced better results when I've used the OP's technique. YMMV.

 

[bob1852]

I'll probably start saving yeast in those 4oz canning jars. Why waste all that headspace with beer, or worse, water. Right?

 

[grndslm]

Yeast washing is a completely unnecessary step that is more harmful than it is beneficial. Beer is a significantly more hostile environment to house microflora than boiled water. Boiling does not kill spores (water has to be autoclaved to kill spores), and most water supplies have a pH that is significantly higher than beer, which will allow the spores to germinate. The proper way to separate yeast from the trub is to leave enough fermented beer behind after racking to be able to swirl the viable yeast back into suspension. Dead yeast cells and the heaviest fractions will quickly settle out, leaving mostly healthy yeast in suspension. It is beneficial to the health of the culture bring a small amount of the protein fraction of the trub over with the yeast.

Commercial breweries only wash their yeast when they are performing an acid wash in an attempt to salvage a crop that is infected with house microflora. The pH of the solution that is used during acid washing is significantly lower than that of tap water.

Good post!

The only difference between what a brewery does and what I do is that they use the SAME yeast for the SAME recipe. If I'm using the SAME yeast for a DIFFERENT recipe, rinsing definitely has its own benefits.

Grndslm, you'll have to forgive me for not taking the "time and effort" to offer a full point-by-point reply, but I would like to make a few comments.

Forgiven.

I will agree that waiting 87 minutes may not be a big deal ... unless you want to go to bed, go to work, go to a movie, go out to dinner, etc....

You can certainly do all those things while waiting. That's the entire point that it isn't any extra "effort", other than the few seconds it takes to toss the jars and water into the freezer/fridge. Time, yes.. but time is something that a brewer should have plenty of. So the point is moot.... but to each his own. This is NOT the reason for either of us choosing or not choosing to rinse or save/pitch a yeast cake, however... so perhaps we won't dwell on this much longer.

I hit my mason jars with a few squirts of StarSan from a spray bottle. Quick and easy. You imply this isn't good enough when you write that boiling the bottles in water for 5 minutes is the proper method because it sterilizes them. We'll have to agree to disagree on this point. At the very least, you may want to research the difference between 'sterilizing' and 'sanitizing' before you make more posts on this topic.

I have searched the difference between the two, before, but perhaps not researched the topic. From my understanding, sanitizing (star san, idiophor) removes 99.99% of microorganisms, whereas sterilizing (boiling, autoclaving) removes 100% of living microorganisms. Apparently autoclaving removes spores, but boiling still goes a step further than sanitation. Perhaps I am missing something else??

You also seem convinced that Bernie Brewer's 'yeast washing illustrated' approach is the proper way to rinse yeast and that other methods, like the one Steven Deeds used, are wrong. Since you indicate that you've read "Yeast" by White and Zainasheff, you've realized they also do it wrong. How embarrassing. If you let them know, maybe they'll fix this in the 2nd edition.

I actually don't quote Bernie Brewer's approach at all. And I did quote to you wolverinebrewer's approach as the proper way to rinse yeast. Perhaps you should check again. I'll just quote my earlier post....

To learn how to rinse properly, see the link I shared earlier, which is also in my signature [HINT: This is not Bernie Brewer's post]. Pay particular attention to wolverinebrewer's posts, which I will link directly here ---> image && process to get that "100% yeast".

I've used the 'yeast washing illustrated' technique many times. I've also used the OP's 'why not to pitch...' technique many times. I'm not here to evangelize for one technique over another, but I will say that, overall, I've experienced better results when I've used the OP's technique. YMMV.

And yes, I'm not here to evangalize any method, but I am here to learn. I'm not sure how much fungus spores or whatever are actually going to survive a boil, and how many microorganisms, flora are "introduced" from boiled water.... but I'd certainly like to learn more on the topic. As of right now, I stick with this OP's suggestion that yeast count is important... however, I propose that rinsing properly will separate ALL trub away from the yeast and will yield the most accurate estimate of yeast count for home brewers. Removing the trub is also beneficial when not repeating the same recipe, as every real brewery does. To each their own, for sure... but I'm definitely not beyond learning.

 

[jwalker1140]

Time, yes.. but time is something that a brewer should have plenty of. So the point is moot.... but to each his own. This is NOT the reason for either of us choosing or not choosing to rinse or save/pitch a yeast cake, however... so perhaps we won't dwell on this much longer.

Actually, this is the reason, along with the fact that I've experienced better results following the OPs approach. I'm not sure why you're so determined to argue something that's a matter of personal perception. Personally, I don't have all of this free time you seem to think brewers should have. And even if I did, I wouldn't be willing to waste any of it doing something that hasn't made my beers better.

At this point I'm starting to repeat myself, which is my clue that I need to move on. Happy brewing.

 

[EarlyAmateurZymurgist]

Good post!

The only difference between what a brewery does and what I do is that they use the SAME yeast for the SAME recipe. If I'm using the SAME yeast for a DIFFERENT recipe, rinsing definitely has its own benefits.

There is still no advantage to washing yeast with boiled water. In fact, washing yeast with water is detrimental to the health of the culture, as it raises the pH of the solution and removes all of the nutrients. If one is brewing a different recipe, all one needs to do and should do is to decant the liquid fraction of the crop and replace it with new wort before swirling the solids back into suspension.

 

[EarlyAmateurZymurgist]

Since you indicate that you've read "Yeast" by White and Zainasheff, you've realized they also do it wrong. How embarrassing. If you let them know, maybe they'll fix this in the 2nd edition.

Please elaborate on how White and Zainasheff are "doing it wrong" in their book? I need to go get a bowl of popcorn because this thread is about to get entertaining.

 

[jwalker1140]

Please elaborate on how White and Zainasheff are "doing it wrong" in their book? I need to go get a bowl of popcorn because this thread is about to get entertaining.

I wasn't suggesting that I think they are. I was inferring that since Grndslm has argued that the technique he happens to prefer is "proper" and that people who do it differently are doing it wrong, that he must also think White and Zainasheff are doing it wrong since they also do it differently. Believe me, I'm nobody to challenge White and Zainasheff on this topic.

 

[grndslm]

Like I said, it's been over a year since I've read the book. If they are getting trub, however, like the guy's blog you linked to... they are doing it wrong.

One more time... if you're getting trub in your rinsed yeast, you are doing it wrong.

To learn how to rinse properly, see the link I shared earlier, which is also in my signature [HINT: This is not Bernie Brewer's post]. Pay particular attention to wolverinebrewer's posts, which I will link directly here ---> image && process to get that "100% yeast".

I've only rinsed yeast a few times, but I never get any trub if I'm using an autosiphon. Regardless of if I use an autosiphon or I pour, the yeast always manages to do its job. So, hey, maybe neither of us is doing it wrong. But I can say, undoubtedly, the guy in the blog that you linked to is doing it wrong.

 

[grndslm]

If one is brewing a different recipe, all one needs to do and should do is to decant the liquid fraction of the crop and replace it with new wort before swirling the solids back into suspension.

And in order to do that, you'd need to wait anywhere from 3 to 7 days, in order for that least flocculant yeast to drop.... otherwise you aren't going to preserve the "integrity" of the yeast.

But everybody knows that people who save/pitch yeast cakes don't have any time to wait....

 

[EarlyAmateurZymurgist]

And in order to do that, you'd need to wait anywhere from 3 to 7 days, in order for that least flocculant yeast to drop.... otherwise you aren't going to preserve the "integrity" of the yeast.

But everybody knows that people who save/pitch yeast cakes don't have any time to wait....

Preferably, one doesn't want to carry the least flocculent yeast over to the next fermentation. In a pure culture, the least flocculent yeast cells tend to be respiratory-deficient mutants.

The photo shown below contains a plate that I streaked from a yeast culture that was harvested from a bottle of bottle-conditioned beer. The small colonies are more than likely respiratory-deficient mutants (a.k.a. petite mutants or simply "petites"). The colonies in the rectangle are the reference culture.