Purposefully stressing yeast

Even if that's the case, pitching by volume as is being suggested... 1L of yeast from Wyeast is a liter filled about 35% of the way with yeast and then on top is beer. Harvesting a liter of yeast, when it eventually settles, a 1 liter crop results in very little beer on top... maybe an inch worth.

I'm also confused about where this advice to use higher pitch rates on harvested year comes from. At Siebel we never discussed that being necessary, nor at Doemens. Many breweries don't know that they are underpitching first generations and then they harvest yeast way too late and end up with dead yeast... maybe that's where this comes from. As is, harvesting the day after the beer reaches terminal gravity, viability has always been 95% and higher

 

Needless to say but “higher” and “under” are qualifiers which need a baseline for those words to make sense.

The below sentence is from the Beersmith website:

“George Fix’s book “An Analysis of Brewing Techniques” recommends pitching rates of 0.75 million cells for an ale and 1.5 million cells for lager.”

The proper units for the case of ales should be 0.75 million cells/ml/°P.

John Palmer in a BYO article further discussed the George Fix pitching rate:

“What is often not mentioned is that this recommendation is for re-pitched yeast — such as you would get from the bottom of the fermenter from a previous batch. That yeast is not at peak vitality (i.e., health) and viability (i.e., % alive), depending on age in the fermenter, previous original gravity, etc.”

So the situation here is that George Fix made a recommendation (a rule of thumb if you will) of 0.75 million cells/ml/°P when pitching an ale yeast that was previously used to ferment a batch of beer. In other words, if you are using yeast that has been ‘beat up’ via a prior fermentation the recommended pitch rate is 0.75 million cells/ml/°P.

When a homebrewer purchases yeast from a yeast vendor (e.g., Wyeast, White Labs,…) that yeast is newly propagated which has not been ‘beat up’ from a previous fermentation. Yet the ‘popular’ online yeast calculators such as the Mr. Malty Yeast Calculator start off with the assumption that when a fresh pack of yeast is utilized that the ‘proper’ pitch rate should be 0.75 million cells/ml/°P. This assumption could be characterized as being a conservative assumption or a stronger way to discuss this would be this value of 0.75 million cells/ml/°P is just plain wrong for the case of ‘new’ yeast.

Now, I have no idea what you were taught at Siebel but permit me to perform a summary of sorts:

· If a brewer is pitching yeast that was previously utilized to ferment a batch of ale then the George Fix recommended pitch rate is 0.75 million cells/ml/°P

· If a brewer is pitching ale yeast from a ‘new’ package of yeast from a yeast vendor (e.g., Wyeast, White Labs,…) then the pitch rate of 0.75 million cells/ml/°P is not applicable

Now, a brewer (either a commercial brewer or a homebrewer) can use the George Fix recommended pitch rate of 0.75 million cells/ml/°P for a ‘new’ package of yeast if they so choose but to state that this pitch rate is the one to use for ‘new’ yeast is not appropriate.

OK, with that out of the way let’s discuss the ‘crazy aunt in the attic’. No brewer (either commercial brewer or homebrewer) can accurately achieve a given pitch rate (whether that value be 0.75 or some other number) unless they have an accurate yeast count. As I have previously discussed in this thread, even a microbiologist who is experienced/skilled in using a hemocytometer and performing the process of a methylene blue yeast cell count will result in an ‘answer’ that has a non-trivial error bar associated with it. The other challenge is that as the yeast sample ‘ages’ the yeast cell viability/vitality decreases. Once the yeast viability get below a certain value then the accuracy of performing a yeast count with a hemocytometer and methylene blue gets even worse.

Cheers!

 

About 20 years ago, George Fix said in his book that 0.75 million cells/ml/P is a good pitch rate, apparently mentioning it in the context of re-pitching. AFAIK, Fix didn't specifically comment on an appropriate pitch rate for "fresh" yeast (you know, the kind of yeast that spontaneously appears out of thin air, and then remains "fresh" for exactly 6 months). I believe Jack's logic is that if 0.75 million cells/ml/P is good for a re-pitch, then obviously you need less if pitching "fresh" yeast.

 

You've stated dozens (maybe hundreds) of times that 0.75 million cells/ml/°P is not appropriate for fresh yeast. What pitch rate do you personally target for fresh yeast? I know you don't count cells, but when you're planning a beer, what's your estimated target?

 

I can't say that I've ever read George Fix's book, but I can say that the methods described in the third edition of "Technology Brewing and Malting" corroborate with a few things I've posted...

1. It describes lager fermentation and pitch rates which would equal roughly 1.5 million cells/ml/P. It does not differentiate between freshly propagated yeast from slants and harvested yeast.

2. When discussing harvesting, it mentions 2l of harvestable thick yeast slurry per hL brewed. If brewers are harvesting 1 gallon per barrel to repitch, that is a HUGE amount.

3. Palmer mentioning dead yeast or low vitality yeast being pitched is already a problem. Yeast, when properly harvested, shouldn't be "beat up." It should be very healthy. If you wait until after warm conditioning, cold crashing, and initial clarification, than yeah, you've got dead yeast. You also shouldn't have yeast in the cone to harvest because yeast dumps should have been performed multiple times already.

4. You can certainly get away with pitching less yeast in your first generation, but that yeast shouldn't be expected to yield a healthy crop post-fermentation, even if the beer is delicious, that yeast has already been mistreated. Compensating by pitching more in subsequent generations only leads to more abuse on the yeast.

5. Inaccuracies with cell counts typically refers to inaccurate assessments of dead vs. live cells. Methylene violet is far better for being able to differentiate between the two. In cases of missed counts, it is good practice to take at least 3 samples and count each one o make sure your counts are consistent. The most common reason people mess up the total count is because their sample wasn't homogenous or they were inaccurate with their dilutions.

 

And to add, when using tasting panels we never noticed differences between 1st and second generation fermentations, that was one of the first things we tested when I trained them. If we used a lower pitching rate for the first gen and then went to .75 on the second gen, I can't imagine the results would stay the same.

 

I simply pitch per the recommendations of the various yeast vendors. It really is as simple as that.

In another 6 months (or whatever) you can ask me this question again and my answer will still be the same.

 

I certainly read what you are stating here.

This is immaterial to me as a homebrewer since I use a freshly manufactured yeast package for my brews. I have batch number 388 going right now so that means that so far I have purchased 388 packages of yeast.

Lately I have been using dry yeast for the majority of my brewing: cheap and easy.

Cheers!

 

I frequently think that if I were to start home brewing again I would be using dry yeast when the strains I want are available dry. Dry yeast quality has improved greatly over what it was when I first started brewing in 2008.

 

So you don't have any target pitch rate. Yet you have audacity to tell people their recommended pitch rates are not appropriate.

 

Simply stating the facts.

The next time you think of that fancy word of "audacity" I would strongly recommend that you look in a mirror.

 

My use of dry yeast in my homebrewing has greatly increased in the past few years.

I started homebrewing in the 90's.

Cheers!

 

Opinions.

Alrighty then.

 

You two have been dancing for years. Vike you just have to let Jack be Jack and vice versa. We are all taking the advice and research with an understanding that it's work in progress.

 

As long as opinions are stated as facts, I'm going to challenge them, whether it's Jack or anyone else. It would be nice if everyone had your understanding, but I think we know how forums work. A lot of newbrewers log on and either search or ask a question. They take the answer they get or find, and consider it gospel if it's stated that way, particularly if posted by someone with a high post count.

The truth (in my opinion!) is that there's no specific recommended pitch rate that's "appropriate" in every situation. It depends on style, strain, brewer preferences, and even on brew house setup. But if someone's going to sh*t on a particular recommendation, they ought to be able to provide an alternative recommended rate.

In my opinion, pitch rate matters, and different pitch rates yield different results, which is why I firmly believe the manufacturer's "one pack/vial per X gallons of 1.xxx wort, up to Z months old" are dumbed down and detrimental to making great beer.

 

Yeast, p. 122

 

Holy crap! You could be saving some money...

I do agree with you that dry yeast is pretty awesome these days. Also the average sachet contains twice as many live cells as WLP or Wyeast liquid packs (when fresh), so depending on other opinions, you can consider whether to use only a half-packet of dry yeast or whatever per 5-6 gallons instead of the whole thing, all else being equal.

Cheers.

P.S. I'm still weighing each side of the Joanie loves Chachie arguments. No sides taken as of yet.

 

I do agree with most of the above.

My own opinions in my own words:

Pitch rate should be based on experience with each particular strain. There should be no hard & fast rules for ale vs. lager or anything like that. Each strain has its own quirks. Any gospelized rules of thumb or opinions to the contrary should be accepted with grains of salt. If no personal experience with a particular strain, then take a best guess, based on mrmalty or whatever else. But if you *really* want to know what you are doing and how to learn from your experience in future, then you should keep track of how much you pitch, how fresh it was, all the details.

Personally, I don't count cells under a microscope. Do I make consistently awesome beer? Hell no. Would it matter if I did count cells? I don't know. Actually I don't think so. But don't know. Am I going to do so in the future? Hell no. So am I screwed with respect to consistency and awesomeness? Maybe. Does it matter? Uh...

Grains of salt.

 

Ah, that actually makes me more skeptical. Chris White is very smart and clearly knows a shit ton about yeast, but his methods are questioned by other microbiologists fairly regularly. I remember Graeme Walker telling a group of us that Chris has a lot of great ideas but that he also has published a lot of misleading things. Specifically, we talked about the recommendation to store yeast under distilled water. That recommendation to pitch less yeast for first generation cultures goes against many years of research and publications. Having more than one person's data is necessary to reliably overturn all the research that has been done.

 

Chris White is very good at turning a small amount of yeast into a large amount of yeast, and for that I thank him profusely. But IMO he is no more an authority on brewing than many of the people on this forum.