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Author Topic: Did I over pitch?  (Read 2531 times)

Offline erockrph

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Re: Did I over pitch?
« Reply #15 on: September 24, 2020, 03:03:22 pm »
Well, I will try to remember to come back to this and let you all know how it turns out in a month or so.

Thanks for the input....guess I will just use one or two packs in the future.
Regardless of the number of packs you pitched,  the beer will be just fine. I probably would have pitched 2 packs at that gravity, but a factor of 2 difference with a yeast pitch isn't a huge deal.

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Offline wst

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Re: Did I over pitch?
« Reply #16 on: October 30, 2020, 12:08:38 pm »
For those of you who may like to know.   This stout turned out very well.   I let it stay in the ferment vessel for 3 weeks with a final gravity 1.022 ABV 7.6%.   I thought the final gravitiy would end up lower, but that is ok and was in the expected range for the final gravity.  I bottle, and used 4.8 oz of primer sugar for a little under 6 gals.   Nice head, very drinkable. 
 

Offline Saccharomyces

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Re: Did I over pitch?
« Reply #17 on: October 31, 2020, 10:45:53 am »
I use this information from Fermentis: https://fermentis.com/wp-content/uploads/2019/10/Brochure_Tips_and_Tricks_BAT_BD.pdf where they recommend .5-.8 per liter for Ales (below).

That is a very good document and your results speak for themselves.  However, I would like to discuss something that is covered in the document under the "Quality Control" section.

Quote
WHEN PITCHING AT 50 G/HL FOR ALE OR AT 100 G/HL FOR LAGER, contaminations are lower than 1 contaminating cell (*)/ ml (**).

As I have mentioned many times and covered in great deal in my blog entry entitled "Yeast Cultures are Like Nuclear Weapons" (https://www.experimentalbrew.com/blogs/saccharomyces/yeast-cultures-are-nuclear-weapons), pitching rates are more about out-competing competitors than anything else.   Granted, in high gravity beer, we have the double whammy of lower O2 absorption and higher osmotic pressure that requires us to pitch higher cell counts due to the increased difficulty of growing biomass combined with increased premature cell death due to high osmotic pressure, but most fermentations are not high-gravity fermentations.  A pitching rate of 50G/hl equates to a per gallon pitching rate of 50 / 26.4 (gallons in hecto liter) = 1.89 grams.  For the typical 5.5 gallon starting wort volume, that equates 5.5 * 1.89 = 10.4 grams, which is why the dry sachet size is 11 grams (the metric equivalent of the 5-gallon batch is 24 liters, which is 6.3 U.S. gallons, so 11 grams is still good enough).  When pitched at this rate, what prevents a fermentation from fully attenuating is a combination of strain genetics, wort composition, and dissolved O2 demand.   Let's face it, a lot of amateur brewers are aeration challenged.  In poorly aerated wort, it is not the pitching rate that controls fermentation, it is a yeast strain's genetically programmed O2 demand.  I have previously covered Brian Kirsop's work on O2 demands from his seminal paper on the subject entitled "OXYGEN IN BREWERY FERMENTATION" (https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1974.tb03614.x), but here are the O2 classes from that paper again:

Class O1 - yeasts whose oxygen requirement is satisfied if wort is half saturated with air
Class O2 - yeasts whose oxygen requirement is satisfied if wort is saturated with air
Class O3 - yeasts whose oxygen requirement is satisfied by oxygen-saturated wort
Class O4 - yeasts whose oxygen requirement is not satisfied by oxygen-saturated wort
 

That being said, I believe that the most popular yeast strains in amateur brewing fall into the O1, O2  O2 demand range, which means that most have O2 demands that can be met by saturation with air.  For example, below is the strain information for NCYC 1026, which is the Whitbread B strain.  We know this strain as Wyeast 1098, White Labs WLP007, and Fermentis S-04. We see that the strain has an O2 demand of O2.  We also see that it has above taste threshold lactic acid production, which is why beers that have been fermented with it have a tart edge.  What most brewers do not understand, it that this yeast strain did not make its mark in brewing in batch-based fermentation.  While the strain was deposited in 1958, it made its mark in the mid-sixties with A.P.V. continuous tower fermentation vessels, which are basically bioreactors designed for continuous beer production. I suspect that the reason why this yeast strain does so well when propagated in a bioreactor is because it did so well in A.P.V. continuous tower fermentation, which means that it probably comes out a bioreactor with enough ergosterol and unsaturated fatty acid (UFA) stores that it is almost insensitive to wort dissolved O2 level.

NCYC 1026

Information
   Flocculent
NewFlo type flocculation.
       1:5:4:5:5
      O2, DMS 33 µg/l, low acetic, high lactic (which is why the strain produces slightly tart beers),
       diacetyl 0.42ppm only, used commercially in Tower Fermenters (continuous process),
       non head-forming, no estery flavour. Contains 2µ plasmid.
Depositor
   British Brewery
Deposit Name
   Saccharomyces cerevisiae
Month of deposit
   June
Deposit Year
   1958
Habitat
   Ale production strain.

Continuing, most of us have experienced long fermentation onset times with BRY-97.  Is that because we underpitched?  Or is it because we did not bother to aerate the wort?  Could it be that the long delay in the onset of active fermentation is the result of BRY-97s inability to come out of bioreactor-based propagation with fully-charged ergosterol and UFA reserves?  Or is it that the strain suffers high cell death in the drying process? Could it be that the isolate has higher O2 demands than its parent BRY-96? Or are we just spoiled by isolates of BRY-96 that work faster than the original? On the Siebel spreadsheet that I received from Lallemand, BRY-96 is labeled as having a fermentation progress of "slow."  How many people consider Wyeast 1056, White Labs WLP001, or US-05 to be slower performing than other cultures?  Finally, why does BRY-97 act normally when it is repitched? Is it because we are pitching a much higher number of cells? Or is it because we are aerating the wort?  Granted, higher pitching rates do reduce the need for aeration, at least, for one serial re-pitch.  Maybe, I will get around to running an experiment where I highly aerate wort before pitching a single pack of BRY-97.
« Last Edit: October 31, 2020, 04:17:16 pm by Saccharomyces »

Offline BrewBama

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Did I over pitch?
« Reply #18 on: October 31, 2020, 11:09:13 am »
All great insights.  If you do decide to run tests on Bry-97, here is my data point:

When I drain my BK, I run it thru a fine mess strainer in an attempt to catch trüb and foam the wort.  I fill the cone or a bit more of the FV and stop.  I then literally dump the yeast and Fermax into the wort. I don’t sprinkle it on top.

I then continue to fill the FV thru the strainer to the 5.5 gal mark creating more turbulence and foam. I then throw the TILT floating hydrometer in and install the lid.

I use a blow off tube attached to the lid via an elbow with the tag end place in a half filled pint jar of Iodophor/water mix. I can just about set my watch by the first ‘blip’ I see on the data log. I see that first blip at 16 +/- 2 hrs just like clockwork.

To get my pitch rate, I use the Lallemand Pitch Rate Calculator. Below is a screen shot of my last brew. I pitched 13 grams and the first ‘blip’ was logged at 14 hrs after I pitched the yeast.



Most of my Bry-97 beers finish fermenting in ~ 5 days.  I’ll close transfer to a CO2 purged keg fitted with floating dip tube and cold crash under CO2 pressure for at least 3 days — longer if I don’t have an open serving spot. Once I move it to the serving spot I tap it, fine it, pull a cloudy pint, and the next day pour crystal clear beer.

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« Last Edit: October 31, 2020, 11:27:00 am by BrewBama »

Offline denny

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Re: Did I over pitch?
« Reply #19 on: October 31, 2020, 11:32:51 am »
While I find all this theory intriguing all I really care about is how the beer tastes. And my experience is that any lag in BRY-97 does not impact flavor. 
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Offline Steve Ruch

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Re: Did I over pitch?
« Reply #20 on: October 31, 2020, 11:59:08 am »
While I find all this theory intriguing all I really care about is how the beer tastes. And my experience is that any lag in BRY-97 does not impact flavor.
The only time that I used BRY-97 there was a lag, but the beer came out great. I have two packs in my fridge waiting to be used.
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Offline denny

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Re: Did I over pitch?
« Reply #21 on: October 31, 2020, 01:08:42 pm »
While I find all this theory intriguing all I really care about is how the beer tastes. And my experience is that any lag in BRY-97 does not impact flavor.
The only time that I used BRY-97 there was a lag, but the beer came out great. I have two packs in my fridge waiting to be used.

It's become my go to dry yeast for American styles.  Can't recall ever having a lag more than 48 hours.  Last couple times it's been more like 16.
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Offline Saccharomyces

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Re: Did I over pitch?
« Reply #22 on: October 31, 2020, 04:36:03 pm »
While I find all this theory intriguing all I really care about is how the beer tastes. And my experience is that any lag in BRY-97 does not impact flavor.

That is the point.  The who thing about pitching rate is to ensure that the culture owns the wort. However, if one's brewery hygiene is sound, then the risk of an infection taking over the fermentation is significantly reduced.  I seriously used to push things when I would innocculate 40ml of 1.020 autoclaved wort with just a one or two loopfulls of yeast.  The reason why I was able to do so was because I was using aseptic technique to transfer yeast into absolutely sterile wort.  If I had not used aseptic transfer technique and just boiled wort, the process would be hit or miss.

Once again, pitching rates are about ensuring that the pitched yeast owns the wort.  They are not about flavor or terminal gravity.  Flavor is the result of wort composition and its carbon to nitrogen ratio as well as yeast genetics.  Terminal gravity is about yeast genetics and dissolved O2.  The reason why the suggested pitching rate for lager is twice that of ale is due to the fact that the replication period is extended at colder temperatures.  It also helps to mask high carbon to nitrogen ratios by reducing replication count.  If aerated well, the typical larger will ferment to completion with ale pitching rates.  It will just take longer to do so. Plus, lager yeast has the advantage of being cryotolerant.  Very few wild microflora exhibit cryotolerance at a level high enough to compete with lager yeast strains.  Cryotolerance is the main reason why lager beer made brewing at the industrial level possible.