Temp of secondary when adding Campden and sorbate?

[Greytop]

I'm cold crashing (40° F) 4.5 gallons of hard apple cider before racking it to the secondary. I plan to add potassium sorbate (2.5 tsp) and Campden (.25 tsp) to the secondary before I add pomegranate juice. It will be kegged and force carbed.

Questions:
1) are the sorbate and Campden quantities correct?
2) do I need to bring the temperature of the cider back up to 68° before adding them?
3) how long should I wait before kegging to let the sulfur off-gas?

Thanks for your help!

 

[RPh_Guy]

I'm assuming US gallons, and that the cider is normal ABV.

The yeast has dropped out of the cider?
Is your Campden sodium or potassium metabisulfite?

are the sorbate and Campden quantities correct?

FYI it's much more accurate to use a scale, with 0.1g resolution or better.

Sulfite antimicrobial activity depends on pH, so it's hard to say. You'd need to test the pH of the cider pomegranate blend to calculate the right amount. At pH 3.5 you'd want around 0.81g potassium metabisulfite in 4.5 gallons, about 1/8tsp. (Assuming 1 tsp = 6.6g)

2.5 tsp potassium sorbate in 4.5 gallons gives roughly 360 ppm sorbic acid, which is too much. 2 tsp should be OK. (Assuming 1 tsp = 3.3g)

Depending on how much pomegranate juice you add, these numbers would increase because it's the final volume that matters.

do I need to bring the temperature of the cider back up to 68° before adding them

Yes, potassium sorbate is not very soluble at cold temperature.

how long should I wait before kegging to let the sulfur off-gas?

You don't want it to off-gas if the amount added was correct. You could rack directly into the keg along with the sorbate and sulfite.

You want around 0.4-0.7ppm molecular SO2 present to prevent bacteria from creating off-flavors, and not have the sulfite cause an off flavor itself.
.... If you can't test pH, you could just aim high and if there's an detectable flavor from the sulfite (like burnt match) you can take action to help off-gas some of it.

Hope this helps

 

[Yooper]

If I was kegging and force carbing, and keeping it cold in the kegerator, I'd skip the sorbate. It imparts a slight flavor that some people don't even pick up, or mind, but I can taste it and don't like it.

 

[Greytop]

RPh Guy: Thank you for the wonderfully detailed answer and for doing the math for me.

Yooper: Thank you for the reply. That's what I did last time. I thought it had completely fermented out and I had racked off the yeast. Friends thought is was great, so I entered it in a couple of competitions. One refrigerated the bottles right away and I scored high. The second left them out at room temp for several days before refrigerating and got geysers. I'd like to be able to bottle off the tap without worry this time. I don't like the idea of adding sorbate but it seems like the only solution.