Experiment - Fermenting Cider w/ Potassium Sorbate - LF Thoughts/Input

[Hieron]

Hey All,

Aldi had cider for $3/gallon so I decided to start a batch of hard cider. It had p-sorb in it, but I like to experiment and the challenge of getting a fermentation going in cider w/ p-sorb was appealing to me, lol. I read a few threads here about cider w/ p-sorb and there seems to be a lot of uncertainty as to whether it can be fermented, so I figured I'd relate my results thus far and get some input from anyone willing to chime in.

So, I made a starter Tuesday evening by pouring about 2/3 of my safale S-04 packet into a pint or so of fresh-pressed cider I'd saved in the freezer from a while back. The next morning, I simmered the cider at a low temp (it was steaming but never bubbled) bc I heard that p-sorb can evaporate out. After the cider cooled down I pitched the starter.

Thursday I had a slow fermentation going - a glug about every 45 seconds. I rehydrated the remaining yeast and pitched it Thursday evening. Today I've got a glug about every 15 seconds - better but still pretty slow.

So there ya go - I have a couple more packets of yeast and I'm trying to decide if I should add some more. It's been about a year since I did a batch of cider but I seem to remember primary being not nearly as vigorous as beer, but certainly more so than this batch has been. Any thoughts?

Either way, if people are interested I'll keep this thread updated with my progress and eventual results for those who want to use real cider in their brewing but only have access to cider with preservatives.

 

[brazedowl]

Well to be clear... sorbate inhibits the yeast from multiplying. So the number of yeast in your brew should be the same number as was in the packet as they can't multiply. You should obtain a VERY slow fermentation that won't pick up... ever. That's the whole reason they put it in there in the first place. To keep their cider... well... cider.

Don't mean to talk down to you if you already knew that...

 

[Hieron]

No worries, but yeah I have a general sense of how it works. From what I understand, the p-sorb binds to the cell wall of the yeast, creating a physical barrier that prevents budding. So my thought was that as it binds like that, it basically gets used up, so eventually if I keep adding yeast some of it will eventually be able to multiply. But I don't want to add too much yeast either, so I'm going about it slowly for now.

Anyway, fermentation has neither slowed nor sped up - still lookin at a glug every 14-16 seconds. So I'm gonna add another half-packet if Safale S-04 and see where that gets me.

 

[Hieron]

Well, I added a total of about 2.5 packs of Safale S-04 yeast to the cider. That got me to a "glug" about every 10 seconds a few days ago. It's slowed back down to about 13 seconds now, so when I get a chance I'm going to check the SG (it has been 12 days now, so maybe primary is about done even at the slower rate). If it's about right I'll call it a success and move the cider off into secondary; if not, I'll probably just be patient rather than adding more yeast.

I don't see the need to update the "glug"-rate every few days at this point, lol, but I will come back and update the thread when I give it a taste.

 

[Hieron]

So idk if this will end up being helpful to anyone or not, but I figured I'd update the thread with my progress on this batch and some general conclusions about trying to ferment cider containing potassium sorbate.

UPDATE

On 12/14/13 (6.5 weeks since I started the batch) I checked the SG and it came out to 1.009 (alcohol ~6.5%). I tasted it at that point, and considering that it took 6 packs of yeast to get it there, I was really surprised! No yeasty or other off-flavors whatsoever! I guess that makes sense considering that the yeast couldn't multiply, lol. The only issue I had with the taste is that it was very tart (think Mike's Hard Lemonade with some apple flavor). I have no idea if this had anything to do with this unconventional fermentation, the particular cider/concentrate I used, the extreme dryness of the finished product, all three, or something I don't know about.

Bottling day was a few days later, 12/17/13. It was actually so dry that the apple juice concentrate I had for back-sweetening wasn't enough and I had to add a significant amount of additional sugar (I just made simple syrup with table sugar for this). Once I was satisfied with the sweetness I added additional priming sugar. Finally, I added some more yeast for carbing, as I was fairly certain whatever was in there had gone the way of the p-sorb. Then I bottled it up!

It's been 11 days since bottling, and I've tried the cider twice in that time. Unfortunately, while the carbing started out pretty good (I used one plastic coke bottle as a rough gauge), it seems to have stalled out. The cider is very lightly carbed - enough to feel a little fizz on your tongue but not enough to see any visible carbonation. I had originally planned to add an entire new packet of yeast to the batch before bottling, but at the last minute I got too worried about ruining the exceptionally clean taste I'd managed to get and did probably less than half the packet. So, almost certainly, the two wonderful options before me are 1) to settle for a near-still cider or 2) to open every bottle, add a bit of yeast to each one, and re-cap.

SUMMARY & CONCLUSIONS

I came across some cider at a good price that contained potassium sorbate as a preservative. Knowing that p-sorb doesn't actually kill yeast but simply prevents replication, I decided to take on the challenge of fermenting the cider. I did this because I like to experiment and because I've seen a lot of wondering and mixed information as to whether it was possible and/or worthwhile to try to ferment cider containing p-sorb.

Long story short, here are the take-home points:

• It took a total of 6 packets of yeast to ferment the 5-gallon batch to completion.
• It took 6.5 weeks to ferment the 5-gallon batch to completion.
• At the end of 6.5 weeks, the cider was extremely tart but had no young, yeasty, or other "off" flavors whatsoever.
• I added approximately 1/2 packet additional re-hydrated yeast prior to bottling, and after 11 days this appears to have been insufficient to adequately carb the cider.

So, bottom line - It IS possible to ferment cider containing potassium sorbate as a preservative. It will, however, cost you significantly more money AND time. If you're thinking that it's worth the extra trouble to save money on cheaper cider, trust me; it's not. The yeast I used is $2.75 USD/packet, so I added $16.50 to my bill and I don't even have a sparkling cider yet!

All that said, if you're really determined to make hard cider at home and cider containing p-sorb is your only option, it can definitely be done!

Future Experiments!?

Some ideas for anyone crazy enough to do some more experimentation on this:

• I added those 6 packets of yeast piecemeal as I realized it would take more than I'd added. I remember reading some reference to "overwhelming" the p-sorb somewhere...maybe if you added all the yeast at once it would almost certainly decrease the fermentation time, and might also decrease the amount of yeast needed.
  
• I gently heated the cider for about an hour because I read somewhere that p-sorb will evaporate out. Maybe I would have had better luck if I'd "cooked" the cider a little higher (mine wasn't really even simmering) and for longer. You'd have to be careful not to ruin the flavor of the cider, though.
  
• It would seem that the yeast's inability to replicate also prevents the creation of off-flavors we usually worry about with cider...If I ever did this again, I would add an entire additional yeast packet at bottling to help ensure that I got sufficient carbonation, and not worry too much about ending up with "young" tasting cider.