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Why use Starters if yeast producers claim its not needed?

jgore21

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Dear BeerSmith users,

I am new to homebrewing and am reading How To Brew, Yeast (White and Zainasheff) and others to learn how to best use, manage and hopefully harvest and propagate Yeast!  As you can see in the subject line my main confusion is this:

Why do homebrewers use starters for 5gal batches of 12 'Plato ale wort if the yeast producers (White Labs, Wyeast, Omega) claim purchased yeast is pitchable straight out of the package and do not need starters to ferment properly?

I understand that a roughly 5 gallon batch of ale wort needs 180 billion yeast cells (at a pitch rate of 0.75 million/mL) to ferment a 12 'Plato batch so any normal package with roughly 100 billion shouldn't be "pitchable" because it is roughly half as much yeast homebrewers suggest using. 

Maybe I am missing something or being too naive in trusting yeast labs but why would they lie?  Aren't they the microbiologists after all?

Please help me clear up my misunderstanding!

Fellow Home Brewer,
John

 
 
You have some good questions.  Hopefully I can shine some light on things for you.

First, there has been a lot of additional understanding of yeast cells and pitching rates since the Zainasheff/White book came out.  As someone who regularly peruses scientific papers, I can tell you there have been a explosion of papers on yeasts in the past few years.

So, getting to your questions.  Yeast companies, such as Wyeast and White Labs, designate their 100 billion cell packages as 'pitchable' for 5 gallons of 12 Plato wort.  Their thinking is that the health of the cells in a recently produced package (within a month or two of packaging date) as such that the yeasts can handle multiple rounds of generational growth without losing their ability to ferment and maintain healthy cell walls to survive in a toxic (alcoholic) environment. 

Much of the pitching rates comes from commercial brewing, where repitches are common and cell wall health may or may not be examined carefully before tossing in a batch of recently harvested yeast.  It aims for a relatively comfortable range of cells which will consume and ferment maltose and other sugars at a quick and predictable rate.  With some of the new findings, people on the home brewing level are starting to look at pitching healthy cells in some ample quantity to get a good fermentation.  This is present in vitality starters and the SNS (shaken not stirred) yeast starter methods which are now being used by many home brewers.

Next thing to realize is that the 'ideal' pitching rate varies from yeast strain to yeast strain.  Some strains do very well and produce desirable qualities when pitched at slightly lower rates (Hefeweizen yeasts and Kveik strains are two that come to mind).  Still others perform better and are better suited to completing a fermentation when pitched at levels above the 'ideal' rate (WY1214 Belgian Abbey is one).  Then there is the desired yeast flavors which can vary based upon pitching rates which I find predominant in WY1272 American Ale II where a lower rate will produce some nice fruity esters while a higher rate will give me a clean fermentation.

Anytime you make a starter, your actual cell count is really a reasonable guess anyway.  Unless, like me, you have the time, energy, and equipment to perform cell counts you really do not know how many cells you are pitching not the health of those cells and the thickness of their cell walls.  You can be assured that you are closer to the model generated number than if you did not make a starter but beyond that...

The net effect is that the yeast strains are very much individualistic and sometimes you need to experiment a little to see how they will perform and what they will produce for you.  Yeast starters can provide a bit of insurance; though these days unless I am making a starter to split, I much prefer to pitch a new packet of yeast into a small batch and harvest from the trub of that fermentation. 

What I can say, is that the yeast companies are certainly the experts and know just what their product limitations are.  I can also say that companies such as Wyeast do tend to make sure there are plenty of cells in their packages.  I don't think I have ever counted less than 100 billion cells in a smack pack and usually the counts are running 5% to 10% more.  I can also tell you that a properly handled package of yeast will have many more cells than the starter programs predict based upon the age of the package.  The environment inside the packaging and the nutrition contained within are plenty to keep the cells happy and healthy.  Of course, if you leave you pack out in the car under a hot sun for the day, all bets are off. 

I think I have answered some/most of your questions.  If there is something you are not clear about or want more information, let us know.  If I don't know, there are plenty of other knowledgeable people here who do.

 
At 12 Plato you are only talking a 1.048 wort. So yes, in that case I wouldn't bother making a starter as long as the package is relatively fresh.
 
Thank you Oginme for your very informative and thorough reply!  Thank you as well Kevin48, knowing a low gravity wort can slide by without a starter is good info.

Oginme, you said that you ?split? your starters but prefer to harvest from a fresh packets fermented beer?  Do you mean you make a starter and harvest some and pitch some?  Why do you prefer to harvest the yeast and trub?  Wouldn?t the yeasts contact with hop AAs compromise the cells?

A lot of questions, I apologize.  I?m a very curious science student turned brewer and would love to check out the literature you mentioned.  Could you please point me towards the journals/labs where the papers come out of so I can check them out too?

John
 
jgore21 said:
Oginme, you said that you ?split? your starters but prefer to harvest from a fresh packets fermented beer?  Do you mean you make a starter and harvest some and pitch some?  Why do you prefer to harvest the yeast and trub?  Wouldn?t the yeasts contact with hop AAs compromise the cells?

A lot of questions, I apologize.  I?m a very curious science student turned brewer and would love to check out the literature you mentioned.  Could you please point me towards the journals/labs where the papers come out of so I can check them out too?

John

I do split starters when I have strung together a series of brews that use the same yeasts and do not want to wait to harvest yeast from a completed batch.  A good example of this was back in December when switching over to lagers for a couple of months, I made a starter and split it into two more starters to get enough yeast to pitch into the first batch and then grow some of the second starter up for the second batch a week later.  Mostly, I harvest from the yeast cake of a batch I have just bottled or kegged.  I harvest by taking some sterilized water into the bottom of the carboy, shaking it vigorously for 3 to 4 minutes and then allowing the heavy trub to settle.  I pour off the suspended yeast back into the sterilized jar and allow that to settle.  If the cell mass is high enough and clean enough I will take a count out of that to pitch, otherwise, I would use that for another starter.  I do this mostly because I am sort of opposed to using good starter wort and then tossing it. 

I also use a variant of the vitality starter by taking a bit of my wort from the batch I just made and adding my yeast pitch to that.  I shake it vigorously to fill the jar or flask with foam and wait for that to show signs of yeast activity before pitching it into the batch.  I do tend to pitch a bit toward the high side most of the time, usually because I can see all the cells, weak and strong in the yeast I have harvested. 

I am not concerned with the hop oils that the yeast have adsorbed from the last batch.  Those cells which are wrapped in a lot of hop oils usually do not replicate themselves well and so will end up as the minority of what gets pitched (some speculation here).  I also have to admit that hoppy beers make up the minority of what I brew.  Usually, those strains I use for hop-forward styles: WY1318, WY1272, WY1450 will find their way back into other hop forward styles.  I track where a harvested batch comes from, generation from original packet, and date of harvest so I can select the yeast cake which best suits the batch I am pitching into. 

I get a lot of my papers and publications from ResearchGate or Academia.edu.  I also have access through my job to SciFinder and occasionally use that to find harder to locate papers.

Lastly, never apologize for being curious.  I am a chemical engineer by training, and work in research and development so I get deep into many different aspects of scientific inquiry over a vast range of topics.

 
I do a vitality starter.  About 600-700 ml of wort and I put on the stir plate 4-5 hours before pitching.
 
Pursue the same approach as you. When brewing a low gravity beer, I just do the vitality starter. I remove half a liter of wort towards the end of the mash, dilute with clear water to one liter, boil it for 10minutes, cool down to room temperature and add the yeast. I then put it on the stir plate which I found to be an essential tool! ? and like you said when it comes to pitching (after aeration!) the starter starts foaming already and you can be sure its healthy.

When I do high gravity beers, I generally prepare one starter two days before brewing with dry malt extract. In the fridge, the yeast settles until brew day when I decant the beer and prepare one more vitality starter with the yeast cake.
 
Throwing in my 2 cents worth.
I am a "seat of the pants" brewer, meaning I don't have an engineering or science degree... I just brew and experiment as I go (for 30+ years). And I have never killed anyone with the result.
With regard to yeast pitches and effeciencies, I usually go with a pack designed for the batch I am making and it always works out just fine.
That being said, I also dump batch as well. Which is that I will make a 3 gallon batch of a lighter alcohol brew such as a dry stout or pale ale. The plan my next batch to be higher in alcohol and complexity which would need a stronger yeast and dump the wort into the yeast cake. The results are always great, and it saves a ton of money to boot.
So I guess in a way I am making a yeast starter, but one that will give me 3 gallons of great beer... Yeah, I'm cheap!
 
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