Rebel Brewer Giveaway!
 Home Brew Forums > Yeast Caluculation Quick and Dirty?

03-29-2011, 06:39 PM   #1
kansasbrew
Feedback Score: 0 reviews
Recipes

Join Date: Feb 2010
Location: , Kansas
Posts: 165
Liked 1 Times on 1 Posts
Likes Given: 3

 Yeast Caluculation Quick and Dirty?

For calculating starter:

So, am I thinking straight? It seems to me that for a 5.25 batch of beer you are looking at plato by a factor of 2 (give or take) and then put your decimal point where it belongs? If you figure a million cells per plato per milliliter times 20,000 milliliters to the batch size (rounded up) it would seem about right. By that math a 12 plato is about 240 billion cells needed per batch?

I realize some people assume more and some people assume less on the cells per milliliter.

And is it right that you take the last two digits of target gravity and divide by four to get plato? So 1.048 = 12 plato and 1.052 = 13 plato and so on?

For a simplification it could be thought of as a 2-4 rule then, i.e., double plato for the cell count and divide gravity by four to get plato. I realize the simplicity only works if you're doing a standard 5.25 batch size.

I'm not great at math, so if I'm not understanding please let me know.

__________________

Last edited by kansasbrew; 03-29-2011 at 06:40 PM. Reason: correction

03-29-2011, 08:07 PM   #2
a10t2
Feedback Score: 0 reviews
Recipes

Join Date: May 2010
Posts: 557
Liked 13 Times on 13 Posts
Likes Given: 1

Yes, if your batch size is 20 L and you're pitching 1 million/mL-°P, then you'll always be multiplying the OG by 2x10^10.

Plato-SG conversion isn't actually linear, but dividing by 4 is probably close enough for your purposes. (0.1°P off at 10°P, 0.3°P off at 15°P, 0.8°P off at 20°P, etc.)

__________________
http://seanterrill.com/category/brewing/
Quote:
 Originally Posted by monty3777 squeeze your sack like it owes you money.

03-29-2011, 08:33 PM   #3
ThePearsonFam
Feedback Score: 0 reviews
Recipes

Join Date: Feb 2009
Location: Virginia Beach, VA, Virginia
Posts: 884
Liked 12 Times on 10 Posts
Likes Given: 1

or, use this handy-dandy calculator...

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

__________________

03-29-2011, 10:46 PM   #4
kansasbrew
Feedback Score: 0 reviews
Recipes

Join Date: Feb 2010
Location: , Kansas
Posts: 165
Liked 1 Times on 1 Posts
Likes Given: 3

Mrmalty does the work for you. That is truly easiest of all. I've just been trying to get more familiar with some of it for the sake of... I'm not really sure why.

__________________