NEW question about a yeast starter that I cannot find anywhere!!!

[HOPSareKEY]

Hello,
I understand yeast starters are talked about at nauseaum, but I have a question that I cant seem to find an exact answer to anywhere.

How do you know how much yeast to pitch into the starter?

Example...
The way i understand it is if i use the ratio of 1/2 cup dme to 2 cups water, one smack pack, and sit on stir plate for 24 hrs. that is good for a beer upto 1.070.
If I have a beer that is 1.090, I know to use 1cup dme to 4 cups water, but do I use 1smack pack and let it sit for 48 hrs on stir plate to let it reproduce more or use 2 smack packs?

How far can one smack pack go?

Any additional input is appreciated and sorry if this has been brought up already. Thanks.

 

[temple240]

Check out some calculators like Mr malty, yeastcalc.com, or the beersmith calculator. They'll tell you how much yeast you need and what size starter will get you there based on cell count and viability.

 

[el_caro]

One smack Pack will go as far as you want. If you can do starters then like has been suggested use yeastcalc.com.
You can play with the different sizes to get where you want to go.
If you produce more than you need for your beer then you can store the surplus - read this thread on rinsing yeast
https://www.homebrewtalk.com/f163/yeast-washing-illustrated-41768/

 

[osagedr]

Gotta use a yeast calculator. Yeastcalc.com is very flexible and now has both a White and a Troester option for your stirplate calculation.

 

[scubasteve03]

the way i understand it is the yeast will reproduce baised on the amount of volume and fermentables. A vial of yeast or smack pack when pitched into 5 gallons will have 1/2 inch or more of yeast in the bottom of the fermentor.

bottom line, just like the others have commented on, yeast calculators will help you determine the volume needed to create the approriate amount of yeast cells needed.

 

[sweetcell]

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