Killing yeast after Ferment

So as I understand it a lot of cider makers like to use something like campden to kill their yeast after fermentation so they can back sweeten with brown or natural sugar. my question is, if I fermented a 4 gallon batch /w concentrate, when fermentation is finished could I add 1 gallon of cider with potassium sorbate in it to both back sweeten and kill the yeast in one fell swoop? Or would the concentration of potassium sorbate be too diluted when added to 4 more gallons of liquid.

Just an idea I wanted to bounce off you guys. Has anyone tried it?

techbrewie said:

So as I understand it a lot of cider makers like to use something like campden to kill their yeast after fermentation so they can back sweeten with brown or natural sugar. my question is, if I fermented a 4 gallon batch /w concentrate, when fermentation is finished could I add 1 gallon of cider with potassium sorbate in it to both back sweeten and kill the yeast in one fell swoop? Or would the concentration of potassium sorbate be too diluted when added to 4 more gallons of liquid.

Just an idea I wanted to bounce off you guys. Has anyone tried it?

Click to expand...

Campden doesn't kill yeast, especially wine and brewer's yeast. So that's not at all correct.

What can happen is that sorbate can be added at the end of fermentation, when there are no new lees droppping and the cider is clear, and then racked away from the spent yeast. Sorbate doesn't kill yeast either, but it keeps yeast from reproducing so often that works to stop fermentation from restarted (but doesn't stop an active fermentation). Sorbate works better in the presence of sulfites (campden), so they are usually added together.

Adding cider with sorbate won't do a thing, for the most part, to prevent fermentation from restarting, and there are plenty of yeast in suspension without racking and sorbating before that.

What is the standard (or average) dosage of potassium metabisulfite and potassium sorbate per gallon to halt renewed fermentation after fermenting dry? There seems to me great debate over these numbers with the appropriate answer actually being "It depends on your PH", but is there a "safe" minimum dosage for something like ec-1118 that ran dry in a cider?

It's never been an issue for me before mostly because I've never had a reason to need to kill yeast. My lagering chamber died with a back sweetened graff in it awaiting an empty keg. :-/ fermentation started up so its a new problem for me. Thanks for the explanation! Lesson learned though, dont back sweeten until its in the keg, and pray the keezer doesn't ever die