Yeast Starter / Pitching Rate

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tiramisu
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Yeast Starter / Pitching Rate

Post by tiramisu »

Trying to get my head wrapped around this a bit.

Looking at DADY
http://bsgcraftbrewing.com/Resources%5C ... s_dady.pdf

Dosage: Use between 2 - 4 lbs / 1,000 US gallons ( 25 -50 grams / Hectolitre) to give an initial pitching
rate of 7 - 14 billion yeast cells / US gallon ( 2.5 to 5 million cells per ml)


There are 453.592 grams in an lb ( freedom units suck)

So .002 - .004 lbs per gallon or .907 - 1.8 grams/gallon
The instructions on the package say 1-2 grams /gallon

Ok, the recipe scales.

Wineos Sugar wash recipe calls for 1/4 cup (32 grams) of DADY per 6 gallons or 5.3 grams/gallon. (5x the mfrs. recommendation).
-- god help me if I am confusing weight and volume here...

So I'm thinking to myself. Self....
The guys always say Dry Yeast is cheap but to me it looks like it adds up pretty quick if you are going to pitch 1/2 a pound for every barrel so....
Rather than pitching 250 grams of dry yeast for every barrel why not make a starter

Then I do the usual look at youtube videos with all kinds of cute instructions and then they pour their starter into a 6-gallon carboy.
Doh!

1 gram of DADY is initially good for 2.5 million cells per ml in a gallon.
But what is my reproduction rate if I make it in a nice temperature-controlled wort?
How much volume of wort do I need? Can I do this in a 2 liter flask?
Do I need to do a 2-step if I start with 50 grams of yeast but want to match Wineos recipe?


Under optimal conditions, yeast cells can double their population every 100 minutes.
Species: S. cerevisiae
https://en.wikipedia.org/wiki/Saccharomyces_cerevisiaec

So in theory I could do 12 doublings in 24 hours if I had adequate wort (with a starter)
(24 if I did a two-step).

... off to do more reading but it seems like I'm missing a bunch of basic information that should be printed on the package or available on the manufacturer's site.

thanks for any clues in advance.
Last edited by tiramisu on Tue Oct 26, 2021 6:37 pm, edited 1 time in total.
greggn
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Re: Yeast Starter / Pitching Rate

Post by greggn »

tiramisu wrote: Tue Oct 26, 2021 6:24 pm
But what is my reproduction rate if I make it in a nice temperature-controlled wort?

Under optimal conditions, yeast cells can double their population every 100 minutes.

Yeast reproduction (budding) is dependent upon oxygenation of the wort. Of course, temperature and nutrients play a role in yeast health but reproduction occurs during the aerobic phase of fermentation.

If I remember correctly, Chris White (of White Labs) said in his book "Yeast" that a single yeast cell typically only buds 1 - 2 times.
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NZChris
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Re: Yeast Starter / Pitching Rate

Post by NZChris »

If I'm short of a particular yeast I need, I propagate it and feed it for a day or two before I need to pitch it. It's not a new idea.
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8Ball
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Re: Yeast Starter / Pitching Rate

Post by 8Ball »

I found this info somewhere on HD and it works for me. I modified it so I use 0.03 g/ppg vs 0.05

○ The number I have been working with is .05 g per point gallon.
○ Find your specific gravity, let's say 1.090. Let's say you have 7 gallons. 90 X 7 X .05 = 31.5g. I'll bet you put in a lot less than that. If that's true it's just going to take the smaller initial yeast population a lot longer to multiply and then begin active fermentation.
○ Don't panic. Add more yeast and/or wait a little while.
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bluefish_dist
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Re: Yeast Starter / Pitching Rate

Post by bluefish_dist »

A lot of the t&t recipes over pitch yeast. Not really a bad thing and for small batches minimal cost impact. Now for big batches yeast is a bigger cost and when some cost $30-$50/lb over pitching is expensive. If you rehydrate and propagate your yeast properly you can get by with less. If conditions are poor, it’s easier to just over pitch. For my vodka I would pitch about a pound of bread yeast for 110 gallons. Would easily finish in 3 days.

Yeast technical data sheets say how to rehydrate. Usually it’s 10:1 water to yeast by weight at 90-100 deg, wait 10 min and pitch. This helps a small amount of yeast get going. Also stirring or agitation of the wash/wort before pitch adds oxygen which is something else yeast needs to propagate. Once the oxygen is gone they stop propagation and start making alcohol. So if you are going to try and propagate more times, you need to oxygenate.

I found pitch ph was critical to helping the yeast propagate correctly. Again look at the tds for the yeast, but usually between 5.2 and 5.6.

Tds, are available on yeast suppliers web sites. Always good to have data.
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tiramisu
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Re: Yeast Starter / Pitching Rate

Post by tiramisu »

Thanks very much... all that was very helpful.
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jonnys_spirit
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Re: Yeast Starter / Pitching Rate

Post by jonnys_spirit »

NZChris wrote: Wed Oct 27, 2021 1:40 am If I'm short of a particular yeast I need, I propagate it and feed it for a day or two before I need to pitch it. It's not a new idea.
+1 to Chris's method

I pretty much always do this. Rehydrate and feed the starter over a day or two with wort/wash/wine/whatever - starting the feeding with a much lower SG than what it's going into and ramping up.. Not particularly scientific but I start a 50g ferment with one packet of US-05 no prob using this method.. If I'm using bakers i'll probably just throw half or the whole jar into the starter and do the same.. Can't say that I've had a stall that I remember but maybe one stall when I was doing an experimental and especially cool ferment on a grape juice bucket - It did eventually ferment but took at least year and I ended up distilling it.

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Ben
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Re: Yeast Starter / Pitching Rate

Post by Ben »

I pitch what is required the first batch (9 grams for 6 gallons on DADY) then pour half the yeast/trub into the next wash at boil to use as yeast nutrient and the other half stays in the fermenter and gets cooled wort added to it for referment. When I add the nutrient yeast I also pull a quart of boiling sterile mash into a mason jar to store for use as a starter. Not very scientific but it works. I run my wash every 10 days so the yeast are always excited for their next feeding. Of course this is most ideal if you are running the same recipe over and over and... over. There is a more scientific write up here: http://www.mrmalty.com/pitching.php#s2

If I am switching yeasts I pull a sanitized mason jar of trub out of the leavings and wash the yeast for storage. Can store unwashed yeast in the fridge for a few weeks or washed yeast with glycerin in the freezer if your not going to use it for a while. Then build a starter out of that, then use the residual yeast in the starter to build up another batch for storage. You can also split your yeast after the first generation and wash and store half... IF your sanitation is good. Usually you get 6-8 generations out of a batch of yeast at the home scale, so if you split it early you can get a lot of mileage. I found in beer the best flavor beer came around the 4th generation of a yeast, it seems reasonable the same would apply to whiskey.

Yeast is easily the most expensive disposable component in the hobby, and also the easiest to reuse. May as well get life out of it. A packet of wlp004 is $9 now. The entire grain bill for 6 gallons is about $8. So split that yeast into 6 or 12 generations, or just buy a yeast once, split and reuse in perpetuity.

Some of the macro breweries have been using the same yeast since inception. Some of the old world breweries in Europe have been using the same yeast for millennia. Coors brewing keeps their yeast in a temp controlled vault, it is only handled by their microbiologists, it is treated as their most valuable asset.
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Demy
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Re: Yeast Starter / Pitching Rate

Post by Demy »

The starter (ie the Chris method) is always a good thing especially with difficult ferments, I don't do it often but it helps. If you go looking for exact numbers and exact count of the yeast population you will probably find a lot of confusion .... I generally use my empirical method 0.5g yeast every liter of beer, otherwise read the manufacturer's indications (usually abundant doses) .
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