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View Full Version : Cold crashing and killing a fermentation questions



egwenejs
03-17-2012, 04:27 PM
I a 2.5 gallon have a cyser I fermented with D-47 that started with a gravity of 1.100 and is at 1.018. So, it should have 11% alcohol and a bit on the sweet side. I want to stop the fermentation here. So, I threw it in the fridge. My questions are:
* How cold should I get it and for how long before adding the sorbate and sulfite.
* The guy at the homebrew store said 1/4 teas K Sorbate for 5 gallons, so is 1/16 t per gallon about right?
* How much K Metabisulfite should I use? I'm thinking 1/2 t per gallon.

TAKeyser
03-17-2012, 05:10 PM
I a 2.5 gallon have a cyser I fermented with D-47 that started with a gravity of 1.100 and is at 1.018. So, it should have 11% alcohol and a bit on the sweet side. I want to stop the fermentation here. So, I threw it in the fridge. My questions are:
* How cold should I get it and for how long before adding the sorbate and sulfite.
* The guy at the homebrew store said 1/4 teas K Sorbate for 5 gallons, so is 1/16 t per gallon about right?
* How much K Metabisulfite should I use? I'm thinking 1/2 t per gallon.

According to the directions on mine for a 2.5 gallon batch you would want 1/8 tsp of the K Meta bisulfite and 1 1/4 tsp K Sorbate. Can't help you with the cold crashing as I don't do it, I just rack onto the sorbate and sulfite.

egwenejs
03-18-2012, 02:03 AM
Cool, looks like I was on the right track as far as chemicals. Can anyone way in on cold crashing temps and length?

tweak'e
03-18-2012, 03:10 AM
you only have to get it down past minimum temp which i think is 15c for d47. the trick would be to get it down low quickly otherwise it can ferment past your stopping point.
if you can get it down to 5c it would be good. that way temp won't go up quickly when you rack it.

egwenejs
03-18-2012, 02:20 PM
Nice, my fridge is holding it at 4C. Looks like it's time to sanitize the carboys and rack onto the chemicals.

huesmann
03-24-2012, 09:11 AM
When cold crashing, how do you make sure you get all the yeasties and that there are none left to start fermenting again when the mead resumes room temperature?

TAKeyser
03-24-2012, 10:38 AM
When cold crashing, how do you make sure you get all the yeasties and that there are none left to start fermenting again when the mead resumes room temperature?

Cold crashing alone won't permanently stop the yeast. Once it is brought back to a temp the yeast can be active at it can be brought back to life. My understanding is it will halt the fermentation at a specified Gravity and than allow time for the mead to be racked onto the stabilizing agent and give it time to work while the yeast is already halted since sulfite and sorbates aren't immediate.

tweak'e
03-24-2012, 06:22 PM
you need to let the yeast drop and then rack off the yeast.
then you can stabilize it which stops the yeast from breeding. yeast slowly die off through normal attrition. so you still need to keep it cold for a while after stabilizing.

egwenejs
03-24-2012, 10:36 PM
What I did was to put it in the fridge for a couple of days to stop the yeast working. Then racked it off the lees onto sorbate and sulfite mixture described earlier. It appears to have worked because today (6 days later) the SG is the same as when I racked it -- 1.020.

TAKeyser
03-24-2012, 10:44 PM
All you have to do now is set it aside and forget about it for a while to let it age and clear and bottle when ready.