Author Topic: Pitching rates  (Read 5801 times)

KernelCrush

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Pitching rates
« on: May 06, 2014, 03:49:21 PM »
Reading in the yeast book.  Page 122. They cite the common pitch rate for ales at 750,000/ml/degree Plato which works out to 9 million/ml in an exactly five gallon batch at 12 Plato or 1.048. They say that all published pitch rates are actually based on repitching, cause the rates are geared to probrewers,  who almost always repitch.  If using a fresh lab culture (by that I assume they mean a tube or pack) you can cut your pitch rate by 50% from that recommendation because of unstressed yeast, high viability, high vitality.  Palmer says the same thing in HTB 2006 3rd edition page 63.  A white lab tube has 5.6 million/ml concentration and they suggest 1 tube for up to 1.060 or ~15 P if fresh, which = 375,000/ml at 15 P, exactly 50% of the original 750,000 recommendation for repitching harvested yeast.

I am asking if I am misunderstanding.  If the above is correct I am way overpitching 2x.  My initial pitch I coordinate my order with my suppliers order cycle to get the freshest possible yeast and have been able to get it dated within 2 weeks of production then use a yeast calculator to estimate tubes required with no starter.  The calculators are based on the 750,000 figure by default.

I would never recommend a lower pitch rate but why do the calculators all go against what is stated above in respected books.
« Last Edit: May 06, 2014, 05:21:47 PM by KernelCrush »

KernelCrush

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Re: Pitching rates
« Reply #1 on: May 10, 2014, 03:47:14 AM »
So I sent some questions to White Labs.  They asked me not to quote directly but to put it in my own words.  Below is what they said modified only slightly.  Don't shoot the messenger.

-We have all gone stir (plate) crazy.
-Most of the pitch calculators are giving counts that are higher than needed.  Some feel the need to reach those counts, but typically the 50% mark will still produce great results.
-A portion of the vial certainly contains solids other than yeast as there is a substrate required to keep the yeast healthy. This consists of a malt extract, which by its very nature will contain some dissolved solids, and proteins.
-The pitching rate calculators have an algorithm that produces vastly different suggestions based upon the gravity and volume of wort. This can lead to over or under pitching which can lead to potential fermentation issues. Over pitching can cause early stalling and have limited flavor production, while under pitching can lead to contamination or under attenuation. We have found good, consistent results with the suggested pitching sizes we offer. If brewing in higher gravity it is often a good idea to pitch more yeast as it is a stressful situation for the yeast and it will become tired much more quickly.
-Pitch rate is only one part of a vast number of variables that strongly effect fermentation. Temperature and Oxygen content are probably the two most important factors in a successful ferment.

Offline all grain

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Re: Pitching rates
« Reply #2 on: May 10, 2014, 08:10:40 AM »
stir plate crazy, sounds like a possible disorder. lol , and as far as pitching rates go, I think the best way to look at them is to know that there is a difference in the beer when over and under pitched. knowing that this is a fact and one of many variables is a good starting point for the home brewer to use as a base for possible changes that may be implemented in the beer making process on the  quest for better beer. 
brewing is an art form not just a science ,dude where's my beer!

Offline Ellismr

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Re: Pitching rates
« Reply #3 on: May 15, 2014, 12:51:57 PM »
I'm not an expert but I read a lot of material and John Palmer says that a good rule of thumb is that if OG is 1.060 or less one package/vial is satisfactory.  When you get into imperials and double IPA's OG 1.070 think of making a starter. 

Offline Baron Von MunchKrausen

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Re: Pitching rates
« Reply #4 on: May 15, 2014, 02:34:39 PM »
Interesting observations.
I have read for the home brewer, it's almost impossible to over pitch unless dumping ridiculous amounts.
There are certainly more knowledgeable experts than I ( I've lost interest in the cell counts after the 6th zero...  :)
All I can tell you is my beers have improved dramatically since using starters on a stir plate. My experience is that liquid yeast is woefully inadequate from the vial/pouch on anything coming close to 1.06 OG or more.
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KernelCrush

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Re: Pitching rates
« Reply #5 on: May 16, 2014, 08:25:37 AM »
Everyone has their ideal pitch rate, mine is normally about 10% over the calculators.  I was just pointing out something I missed in my previous read of the yeast book.  White labs recommends 1 tube up to 1.060. He seemed to put more emphasis on dissolved oxygen & temperature management.  Brewers Friend is the only yeast calculator that has an optional 'yeast manufacturer recommended' pitch rate built into it. They say no starter required if your yeast is less than 30 days old and under 1.060.   

Offline durrettd

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Re: Pitching rates
« Reply #6 on: May 16, 2014, 11:56:29 AM »
I use        http://www.yeastcalc.co/homebrew-calculators         if I'm building up a starter with liquid yeast. If I'm using dry yeast I use the "Starter" tab in BeerSmith. Both work well.

Offline jtoots

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Re: Pitching rates
« Reply #7 on: May 19, 2014, 11:54:36 AM »
All I can tell you is my beers have improved dramatically since using starters on a stir plate. My experience is that liquid yeast is woefully inadequate from the vial/pouch on anything coming close to 1.06 OG or more.

How would you summarize the improvement in quality?  Is this improvement from 1.06 and above or for all beers?

Offline Baron Von MunchKrausen

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Re: Pitching rates
« Reply #8 on: May 19, 2014, 01:15:36 PM »
All I can tell you is my beers have improved dramatically since using starters on a stir plate. My experience is that liquid yeast is woefully inadequate from the vial/pouch on anything coming close to 1.06 OG or more.

How would you summarize the improvement in quality?  Is this improvement from 1.06 and above or for all beers?

Early on in my process, I pitched directly from the vial/pouch according to instructions. All things being relatively equal (ferm.  temps, etc) there were noticeable off flavors, more pronounced with higher gravity brews.
A red ale with a hint of honey at 1.062 was the worst. I think I accidentally made Vicks Formula 44.
Also an English bitter at 1.060 had a cooked vegetable and pronounced solvent taste.
Subsequent brews of the same recipe have been wonderful with a starter.
Lower gravity brews haven't experienced the same fate, but with any gravity, reducing the lag time to 4 - 12 hours can't do anything but help.
Even Beersmith, in the "starter" tab, will recommend 3 liquid yeast packs on a 1.06 beer with no starter. I usually make a 2.0 liter starter. Beersmith indicates even that isn't large enough without a stir plate. (2.45).

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