Author Topic: New starter procedure trial  (Read 32945 times)

Offline brewinhard

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Re: New starter procedure trial
« Reply #90 on: October 04, 2015, 03:06:36 PM »
This weekend (Tuesday for me) I'm taking my second run at no stir starters with a pale and a stout. After those, it's lager time. I'm not freaked out about doing it with a lager, but rather keeping an open mind. Honestly, I hope they turn out world class. Why wouldn't I?

Curious to hear firstly how you plan on tackling the lager starters in this method, and secondly your results with the lager starters and batch tastings. 

After reading this thread it looks like 1 pack of lager yeast into 1 L wort (shaken method) inoculated post shaking. Then fermenting around low 70's to increase cell biomass, then once it reaches high krausen, chill to around 50F and pitch all into your cooled batch of wort. Obviously for a normal gravity lager (1.050 or so).  Am I missing something here?

It still seems like such a small amount of yeast, but if there is increased health and vigor, then that may make all the difference. 

Offline brewday

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Re: New starter procedure trial
« Reply #91 on: October 04, 2015, 03:18:11 PM »
It still seems like such a small amount of yeast, but if there is increased health and vigor, then that may make all the difference.

I think you've got it there.  Mark has said before that the only cell count that matters is the viable cell count.
Jon Weaver

S. cerevisiae

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Re: New starter procedure trial
« Reply #92 on: October 04, 2015, 03:56:05 PM »
that makes sense.  I was just looking for the reason why so I can sleep well at night :P

You are overthinking the problem and treating it like black magic when the problem is one of basic biological science; namely, how do we ensure that our culture owns the wort?   We do so by pitching enough cells to ensure that we reach maximum cell density before any invaders have a chance to take control of the wort.  A yeast culture owns a batch of wort by lowering the pH below 4.6, which prevents a whole host of pH sensitive bacteria, including pathogens, from gaining a foothold in the wort.  It also consumes all of the dissolved O2, which prevents wild aerobic microflora from gaining a foothold in the wort.  Finally, a yeast culture produces ethanol, which is toxic to all carbon-based lifeforms at a given level. Brewing yeast cultures have been domesticated via selective pressure to be able to withstand the ethanol levels encountered in brewing.  Most wild microflora cannot withstand the ethanol levels encountered in fermentation (which is why rinsing yeast with and storing it under boiled water is a bad idea). 

A concept that brewer's need to burn into their minds is that fermentation is controlled spoilage.  The key word here is "controlled."   We want the pitched microflora to own the wort.  The problem that we face is that the bacteria cell count doubles three times in the same amount of time that it takes for the yeast cell count to double, and no brewery is sterile.  The difference in replication rates means that the bacteria cell count grows by a factor of 8 (2 * 2 * 2) every time the yeast cell count doubles; hence, we are looking at 8n and 2n growth models for bacteria and yeast respectively when we normalize the growth rates to the time it takes for the yeast cell count to double.


Here’s the  reason why we make a starter:

yeast_cell_count_at_time_t = initial_cell_count * 2(t / replication_period_in_minutes), where t is the amount of minutes that have elapsed since the culture transitioned from the lag phase to the logarithmic phase

bacteria_cell_count_at_time_t = initial_cell_count * 8(t / replication_period_in_minutes), where the t is the amount of minutes that have elapsed since the culture transitioned from the lag phase to the logarithmic phase

Let's look at a situation that we never want to have occur; namely, pitching so little yeast that the culture has to spend 24 hours in logarithmic growth in order to reach maximum cell density (this situation was common in the bad old days).

t = 1440 (24 hours into the logarithmic phase, or 16 replication periods because the average replication period for a yeast cell is 90 minutes)

2 raised to the power of 16 is 65,536

yeast_cell_count_at_time_t = initial_cell_count * 65,536

8 raised to the power of 16 is 281,474,976,710,656

bacteria_cell_count_at_time_t = initial_cell_count * 281,474,976,710,656

If the yeast cells do not own the media long before twenty-four hours of exiting the lag phase and our brewery is not clean enough to eat off of the floor, it’s all over; therefore, we want to ensure that the yeast culture never needs go through more than six to seven replication periods in order to reach maximum cell density (signaled by high krausen).  The reason why we pitch at high krausen is because it shortens the lag phase, which starts replication earlier.

maximum_cell_density_for_1L = 200 billion

Most brewers who use 5-gallon soda kegs start 5.5 gallons of wort in the primary.

maximum_cell_density_for_5.5_gallons =  21 * 200 billion = 4.2 trillion  (5.5 gallons is roughly 21 liters)


our_culture_cell_count_low = 50 billion

number_of_replication_periods = log(4.2 trillion / 50 billion) / log(2) = 6.4 replication periods (or 9.6 hours spent in the logarithmic phase)


our_culture_cell_count_high = 200 billion

number_of_replication_periods = log(4.2 trillion / 200 billion) / log(2) = 4.4 replication periods (6.6 hours spent in the logarithmic phase)

If a replication period is 90 minutes on average at ale fermentation temperature (64-68F),  then our yeast cultures will saturate the wort within 6.6 to 9.6 hours after leaving the lag phase, making the time spent in the lag phase the hold up.  When we pitch a culture that has sedimented (i.e., quiescent cells), we are pitching cells that underwent survival-related morphological (cellular) changes.  They stored glycogen and the disaccharide trehalose.  The also thickened their cell walls.  It takes time after pitching for these changes to be reversed.  Additionally, all replication past high krausen is for replacement only, and mother cells share their ergosterol and unsaturated fatty acid (UFA) reserves with their daughters and their daughters share their reserves with their daughters and so forth; therefore, allowing a starter to proceed past high krausen wastes ergosterol and UFAs.  Ergosterol and UFAs are synthesized by the pitched yeast cells during the lag phase.  The more ergosterol and UFAs a cell needs to replenish, the longer it remains in the lag phase and the higher the O2 load placed on the wort because these compounds are synthesized in the respirative metabolic pathway using O2.

« Last Edit: October 04, 2015, 10:25:47 PM by S. cerevisiae »

Offline narvin

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Re: New starter procedure trial
« Reply #93 on: October 04, 2015, 08:42:05 PM »
It still seems like such a small amount of yeast, but if there is increased health and vigor, then that may make all the difference.

I think you've got it there.  Mark has said before that the only cell count that matters is the viable cell count.

Viable is the wrong word; you should also have > 90% viability after making a starter and letting it ferment out.  I think the claim is that , since yeast at high krausen has not had to deplete reserves of various things needed for growth  in preparation for dormancy, they are prepared to multiply more than yeast from finished fermentation.
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evil_morty

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Re: New starter procedure trial
« Reply #94 on: October 04, 2015, 09:19:16 PM »
that makes sense.  I was just looking for the reason why so I can sleep well at night :P

You are overthinking the problem and treating it like black magic when the problem is one of basic biological science; namely, how do we ensure that our culture owns the wort?   

one of the things I wasn't sure of is if the yeast needed to change something about the wort environment before really doing their thing.  what actually happens during the lag phase is somewhat of a mystery to me.
« Last Edit: October 04, 2015, 09:22:51 PM by evil_morty »

Offline klickitat jim

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Re: New starter procedure trial
« Reply #95 on: October 04, 2015, 10:26:46 PM »
This weekend (Tuesday for me) I'm taking my second run at no stir starters with a pale and a stout. After those, it's lager time. I'm not freaked out about doing it with a lager, but rather keeping an open mind. Honestly, I hope they turn out world class. Why wouldn't I?

Curious to hear firstly how you plan on tackling the lager starters in this method, and secondly your results with the lager starters and batch tastings. 

After reading this thread it looks like 1 pack of lager yeast into 1 L wort (shaken method) inoculated post shaking. Then fermenting around low 70's to increase cell biomass, then once it reaches high krausen, chill to around 50F and pitch all into your cooled batch of wort. Obviously for a normal gravity lager (1.050 or so).  Am I missing something here?

It still seems like such a small amount of yeast, but if there is increased health and vigor, then that may make all the difference.
I'll probably post the heck out of it when the time comes.

S. cerevisiae

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Re: New starter procedure trial
« Reply #96 on: October 04, 2015, 10:38:00 PM »
what actually happens during the lag phase is somewhat of a mystery to me.

One can think of the lag phase as a period where the cells adjust to their new home and get ready for exponential (logarithmic) growth.  The cells need to replenish their ergosterol and UFA reserves because these compounds make the cell membrane more pliable, which makes it easier for a cell to pass nutrients into and waste products out of the cell.  Anything that impacts metabolism impacts replication as well as the ability to attenuate the extract.

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Re: New starter procedure trial
« Reply #97 on: October 04, 2015, 11:14:35 PM »
It still seems like such a small amount of yeast, but if there is increased health and vigor, then that may make all the difference.

Why does a 1 to 19 step seem like a small amount of yeast?  Because some other brewer said that one has to pitch X number of cells per degree Plato per milliliter of wort?   What is the basis for that metric?  What were the environmental conditions under which the metric was developed?  How clean was the brewery? What was the average age of the cells? What amount of hydrostatic pressure were the cells subjected to previously? Without this data, the suggested pitching rates are not very useful in a home brewery.

Commercial pitching rates take into account the high microbial loads encountered in commercial breweries as well as the fact that a large percentage of the pitched cells have been through more than one fermentation, not to mention have had to endure significant hydrostatic pressure in tall cylindroconical fermentation vessels. Young yeast cells are like young humans when it comes to the ability to reproduce.  A 1L starter contains at least 50% new cells, and the old cells were grown under conditions designed to preserve health.  In essence, a starter is a totally different beast.

As I have stated many times, what determines if a fermentation will proceed successfully are the health of the cells going into the fermentation, dissolved O2, and the amount of carbon (and nitrogen) available to the cells.  If we pitch a small amount of cells that are in poor health into poorly aerated wort, we can expect less than stellar results.  If we pitch a normal amount of cells into high gravity wort, we can expect less than stellar results because the effects of high alcohol and high osmotic pressure coupled with lower O2 solubility wreak havoc on the cells and reproduction. 

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Re: New starter procedure trial
« Reply #98 on: October 04, 2015, 11:42:16 PM »
I will add one more thing to this discussion for those who believe that a 1L starter is too small for a 5-gallon batch.  Back in the nineties, Maribeth Raines and Jeff Mellem started a groundbreaking yeast company called BrewTek.  BrewTek sold yeast on mini-slants and yeast culturing kits (Denny's Favorite 50 started out as BrewTek CL-50).  Guess what size Erlenmeyer flask shipped with the BrewTek kit (Denny, you are not allowed to answer this question)?  I will give you a hint.  It was not a 2L Erlenmeyer flask.

Offline klickitat jim

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Re: New starter procedure trial
« Reply #99 on: October 05, 2015, 12:41:40 AM »
I will add one more thing to this discussion for those who believe that a 1L starter is too small for a 5-gallon batch.  Back in the nineties, Maribeth Raines and Jeff Mellem started a groundbreaking yeast company called BrewTek.  BrewTek sold yeast on mini-slants and yeast culturing kits (Denny's Favorite 50 started out as BrewTek CL-50).  Guess what size Erlenmeyer flask shipped with the BrewTek kit (Denny, you are not allowed to answer this question)?  I will give you a hint.  It was not a 2L Erlenmeyer flask.
My guess is a repuposed half pint jelly jar.

Offline narvin

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Re: New starter procedure trial
« Reply #100 on: October 05, 2015, 12:51:20 AM »
Yeah, like anyone made good beer in the 90s.  People brewed mostly English ales then because with their flavor, no one could tell if the fermentation went wrong   :D

Seriously though, the idea of proper pitching rate matters very little with Chico yeast in a 1.060 ale.  Yeast IS like a bomb and will get the job done.  However, when you're going for 88% attenuation on a Trappist clone or want 10 gallons of a dry pilsner, a few points of attenuation or some unwanted esters is a big deal.  These are the kind of beers that higher pitching rates have improved for many homebrewers.  If you're making 5 gallons of a pale ale or hefeweizen, just smack the pack.
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Offline HoosierBrew

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Re: New starter procedure trial
« Reply #101 on: October 05, 2015, 12:59:57 AM »
Yeah, like anyone made good beer in the 90s.  People brewed mostly English ales then because with their flavor, no one could tell if the fermentation went wrong   :D

Seriously though, the idea of proper pitching rate matters very little with Chico yeast in a 1.060 ale.  Yeast IS like a bomb and will get the job done.  However, when you're going for 88% attenuation on a Trappist clone or want 10 gallons of a dry pilsner, a few points of attenuation or some unwanted esters is a big deal.  These are the kind of beers that higher pitching rates have improved for many homebrewers.  If you're making 5 gallons of a pale ale or hefeweizen, just smack the pack.

I agree.
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RPIScotty

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Re: New starter procedure trial
« Reply #102 on: October 05, 2015, 01:07:36 AM »

However, when you're going for 88% attenuation on a Trappist clone or want 10 gallons of a dry pilsner, a few points of attenuation or some unwanted esters is a big deal.  These are the kind of beers that higher pitching rates have improved for many homebrewers.

Stan H.  notes in his first BeerSmith podcast that the Trappists pitch "scary low" amounts of yeast.  It seems that a healthy yeast is capable of transcending pitch rate, starter size, starter style, etc. This should be scalable at our level.


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Re: New starter procedure trial
« Reply #103 on: October 05, 2015, 01:21:10 AM »
However, when you're going for 88% attenuation on a Trappist clone or want 10 gallons of a dry pilsner, a few points of attenuation or some unwanted esters is a big deal.  These are the kind of beers that higher pitching rates have improved for many homebrewers. 

However, that information is a little oversimplified.  There are many ways to control ester and higher alcohol production.  For example, O2 can be used to control ester levels, even in high gravity wort1.  I have already covered the reasons why higher pitching rates are needed in high gravity beers.

[1] Oxygen As A Regulator Of Ester Accumulation During The Fermentation Of Wort Of High Specific Gravity, R.G. Anderson and B.H. Kirsop, http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1975.tb03671.x/pdf


S. cerevisiae

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Re: New starter procedure trial
« Reply #104 on: October 05, 2015, 01:31:53 AM »
My guess is a repuposed half pint jelly jar.

Close, it was 500ml Erlenmeyer flask.  The recommended starter size was 300ml. Guess what?  The approach worked very well.

By the way, then as now, the best selling home brewing yeast culture was BRY 96 (a.k.a. Ballantine "Beer," "Chico,"  Wyeast 1056, White Labs WLP001, Fermentis US-05, and BrewTek CL-10).  Amateur brewing was not all English-style ale, Cascade, Centennial, Chinook, and Columbus bombs were pretty darn common back in the nineties.   Recipes including English pale malt were nowhere near as common as recipes based on American 2-row combined with C60.  Quality English hops were also much more difficult to acquire than the American cultivars, which is why the seeds for the beers that we are drinking today were laid in the nineties (some would say in 1975 with the introduction of Anchor Liberty Ale).