Pitching Rate Question - Home Brew Forums

 Home Brew Forums > Pitching Rate Question

03-12-2010, 03:00 PM   #1
dennyb
Recipes

Jan 2010
Atlanta
Posts: 3

Hello everyone, I have read the forum for quite some time, but this is my first post.

I will be making a Scotch Ale this weekend with an expected OG of 1.083. I just did the math for the starter and came up with about 295billion cells needed for the pitch. That's close to a gallon of starter for a 5 gallon batch, which just seems excessive to me. I normally brew in the 1.050 to 1.060 range, for which I like to use a one liter starter. If you all would be so kind as to check my math, I just can't imagine dumping a gallon starter in to a 5 gallon batch.

Thanks a bunch.

-Denny

03-12-2010, 03:17 PM   #2
samc
Recipes

Aug 2008
Portland OR
Posts: 5,387
Liked 63 Times on 59 Posts

http://www.mrmalty.com/calc/calc.html

decant the liquid off the yeast

03-12-2010, 03:30 PM   #3
wizardofza

Recipes

Jun 2007
Buffalo, NY
Posts: 384
Liked 3 Times on 2 Posts

Instead of regurgitating the info in the article, this is a great read:

http://www.homebrewersassociation.or...astStarter.pdf

03-12-2010, 03:43 PM   #4
dennyb
Recipes

Jan 2010
Atlanta
Posts: 3

Awesome, that shows 2.5L which seems more accurate to me. I'll definitely defer to that calculator, but I wonder why it is so different from what I came up with? At a little over half as much volume it seems like I may have some figures wrong, or that my formula is just too riddled with estimates.

I was under the impression that a 2L starter is good to about double the amount of yeast in a vial (to around 200billion cells). Is that just an incorrect constant that I picked up somewhere?

Here are the constants I use to calculate the amount of yeast to pitch:

750,000cells per milliliter of wort.
5gallons = 18,925ml
Deg Plato -->1.082-->(83/4) = 20.75
2L starter will yield 2(original pitch)

03-12-2010, 03:48 PM   #5
dennyb
Recipes

Jan 2010
Atlanta
Posts: 3

@wizardofza

I have that article, it is that formula that I used to generate the original size of the starter. I'm really just curious as to why it is different.