How much yeast to add to grape juice

Question

If after I have juiced the grapes for wine, and added it into the primary fermentation vessel, how much yeast should I add if the volume of the juice is about 9 to 12 fluid oz? I already know about everything else I'm just a little confused as to how much yeast needs to be added to properly ferment the juice and sugar. And by the way I added a cup of sugar, does that sound about right?

Answer 1

Used for beer  pitching rates you can adapt for wine. Just use the SG of your must.

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

http://www.wyeastlab.com/hb_pitchrates.c...

Read this on this page, "How Does Pitch Rate Affect My Beer?"

http://www.foamblowers.com/Article-Yeast...

http://www.mbaa.com/techquarterly/abstra...

http://www.antiochsudsuckers.com/tom/yea...

What will happen to my wine if I add too much or too little yeast ?

The pitching rate influences the lag phase and general fermentation speed as well as the flavour of the finished wine. Too low pitching rates will result in longer lag phase and higher risk of contamination as well as longer overall fermentation time (and sometimes stuck fermentations). Too high pitching rates speed up the fermentation but can lead to early autolysis.

Wine

http://www.extension.iastate.edu/Wine/Re...

Answer 2

9 to 12 oz?  A TINY amount of yeast is all that's necessary.  Adding extra won't be a problem, since all the yeast will die once it gets too alcoholic, but there will just be more dregs you have to be careful of when you rack it off.

The yeast grows while it's doing its thing, so you don't ever need a lot.  If you have a packet, don't use it all.  Save the rest in a culture for next time.

You're supposed to have a cup of sugar water to prime the yeast in, and then add that to the pressings, but if you just put the sugar directly in the grape juice it should be okay.