My cider yeast won't start!!

I'd love a bit of advice for a cider that I started about 2 weeks ago whose SG (1.050) has not budged. I used 4 gallons of already pasteurized cider, combined with 1 can of apple juice from concentrate, and a 1 gallon starter that I had made a separate gallon of cider combined with yeast that I had previously washed and saved from my last cider brewing.
I had followed previous posts on yeast washing, and although the starter wasn't bubbling like crazy, it was active. I pitched everything, making sure to aerate it as it was going into the carboy, and then stuck it in my basement. The temperature there was about 65 degrees. After about 1 week, nothing was happening. I got worried, bought some dry ale yeast, rehydrated it in water at 105 degrees, and then pitched that. Then, I left for thanksgiving and dropped the temp in the house to 55 degrees. I got back and checked the SG today and found it at 1.050. It tastes sweet, and has no sour or bad tastes.

Before this post, I removed the airlock and covered it with aluminum foil and agitated it for 10 minutes. There was definitely carbonation with this. Current temperature is 63 degrees. I've replaced the airlock and am going to keep it a bit warmer, but I'd love any thoughts on what I've done wrong and how to not repeat this mistake in the future.

Thanks
N

Oops-- you're right. Potassium sorbate in the cider. I guess I just need extra yeast then, right?

NateBrews said:

Oops-- you're right. Potassium sorbate in the cider. I guess I just need extra yeast then, right?

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Sorbate will prevent yeast reproduction. You're going to need a whole lot of extra yeast.

One option (if you have an extra fermenter) is to do a separate batch of ale or cider using a clean-fermenting yeast (like US-05 or Notty). When it finishes and you rack it off the cake, toss this cider on top of that cake. You'll have such an abundance of cells there that lack of reproduction won't be an issue.

i have fermented out a cider with potassium sorbate using a yeast cake as described above. it worked but tasted terrible. 6 months later it tasted just as terrible. after 9 months, i dumped it.

i'd start over with the right kind of cider. it isn't even worth screwing around with IMO

progmac said:

i have fermented out a cider with potassium sorbate using a yeast cake as described above. it worked but tasted terrible. 6 months later it tasted just as terrible. after 9 months, i dumped it.

i'd start over with the right kind of cider. it isn't even worth screwing around with IMO

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I defer to the brewer who has "been there, done that" and got a nasty-tasting result.

NateBrews said:

Oops-- you're right. Potassium sorbate in the cider. I guess I just need extra yeast then, right?

Click to expand...

You could use this batch to back sweeten another, fermented batch.