Brainstorming: pasteurizing a keg of cider...

[Ike]

I've been pasteurizing my bottles of cider for a while now, but I'm moving into kegging and I want to pasteurize my cider when kegging so that I can backsweeten and force carb WITHOUT using sorbate/meta. I have a friend who is pretty sulfite sensitive. She's one of the three people who drink my hooch, so if I lose 33% of my audience, I'm in trouble.

Nothing popped up on a search, so here's what I'm thinking:

Fill the keg as normal. Then, use the "ultra low wattage density" heating elements like others use in their electric brewing systems to heat the cider in the keg. It seems these elements could do the job without scorching the cider. I'm worried the element won't heat the cider evenly unless I'm moving the cider in the keg, so I thought about rigging up a small pump that would draw cider from the dip tube, and run it back into the top of the keg fed by a steel tube similar to the dip tube. The outlet would be under the surface, so no oxidation.

I could just hang both items through the mouth of the keg easily enough. A little trickle of CO2 would help keep the blanket in place once the items were in the brew, or work up some sort of temporary lid. It might be tricky, but I MAY be able to mount both items into a spare lid, that would be pretty slick.

I could heat the cider to a consistent 140*, let it cool, backsweeten, and force carb.

Waddaya think? It's a lot more work than just chucking a few campden tablets, but it'd be cool to avoid them if I could.

 

[ehpower2]

i guess if i was faced with that situation i would bottle a small batch in bottles for your friend.
As for me i have had secuess cold crashing my cider kegging and back sweetening while cold and then carbing as my understanding that as long as things are refrigerated the yeast wont wake up. Mind you that if your cider warms up to room temp the yeast will wake up and start fermenting the sweetening you added.

 

[andrewmaixner]

This situation is what filtering is handy for. Fine, filter to Remove all the yeast, carb, sweeten, bottle.

 

[eigua]

I pasteurize at 165 for 10 minutes because I read that was a good temp for wine pasteurization somewhere... Milk is pasteurized at 161. Here's a pretty good resource with FDA recommended times.

 

[madscientist451]

I could heat the cider to a consistent 140*, let it cool, backsweeten, and force carb.

Claude Jolicoeur in his book: The New Cider Maker's Handbook, states that the recommended pasteurization temperature for cider is 149F.
He also mentions that overheating the cider can have an impact on flavor.
Jolicoeur also talks about doing multiple "stabilization rackings" to get a naturally sweet or off dry cider without back sweetening.
If you can do multiple rackings after chilling to settle the yeast and then keep the keg cold, just above freezing, you should be able to backsweeten, not add any chemicals and not have to pasteurize.
Another consideration is how long it will take to consume the cider.
I back sweeten cider without filtering, chemicals or pasteurizing and just keep it my regular refrigerator with no problems, but it gets consumed in a few weeks or a month. I do let my cider age for 4-6 months (or more) and most of the yeast has settled out so my method may not work for you. I build up decent supply of cider and won't start drinking the 2016 fall vintage until late spring/early summer 2017.
I would suggest just try a sample batch of a few gallons in a keg, no pasteurizing, just backsweeten, carb it up, keep it cold and see what happens.

 

[Ike]

This situation is what filtering is handy for. Fine, filter to Remove all the yeast, carb, sweeten, bottle.

Time to do some research!

Fining AND filtering... here we go...

 

[dmtaylor]

Gelatin, cold, and racking are your friends.

 

[Ike]

SO, would it be safe to expect that fining, followed by filtering with a 1 micron filter, will take care of (virtually, I know) all yeast? Enough that I can then backsweeten and keg, and ALSO bottle from that keg without needing to pasteurize the bottles?

Goin' for the gold, here...

 

[Yooper]

SO, would it be safe to expect that fining, followed by filtering with a 1 micron filter, will take care of (virtually, I know) all yeast? Enough that I can then backsweeten and keg, and ALSO bottle from that keg without needing to pasteurize the bottles?

Goin' for the gold, here...

I'd probably skip the fining, and let the cider clear on its own, then filter with a .5 micron filter. That should do it.

OR, you could use sorbate and skip the sulfite. Sulfites are wonderful antioxidants, and sorbate works better in the presence of sulfites, but it's not strictly necessary. I don't like sorbate because it imparts a small taste that I can pick out and find objectionable, but most people don't notice it.

 

[ericbw]

I think you need a .5 micron (point 5) filter to get the yeast and bacteria.

That's the setup I've used for the same purpose. But I never got around to bottling. So I can't say for sure that it worked

Let it clear very well first!

 

[dmtaylor]

SO, would it be safe to expect that fining, followed by filtering with a 1 micron filter, will take care of (virtually, I know) all yeast? Enough that I can then backsweeten and keg, and ALSO bottle from that keg without needing to pasteurize the bottles?

I think this will work.

I think sorbate still isn't a bad idea, as Yooper suggested. Personally I object more to flavors from sulfite than sorbate, but neither is really all that bad. If you wanted to use sorbate without sulfite, I bet you won't be able to taste it or it won't be bothersome at all, and will help keep the yeast at bay, as would cold storage. But I do see these chemicals as completely optional, especially if you're filtering after fining. You're going to have almost zero yeast left at that point, so they shouldn't get out of control.

Also, I forgot to mention earlier..... TIME is also your friend. In any case, if you want let the clear cider sit for a month or two before bottling, any remaining yeast will truly be VERY tired and not affect your bottling plans.

 

[Ike]

UPDATE: I can't imagine any of the original responders care much anymore, BUT for those who may end up searching the topic in the future:

The most important point I want to pass on: I've found that even using just a 1 micron filter can really mess with flavor in certain additives. I didn't seem to notice too much change in flavor when filtering a simple, apple + sugar = cider recipe. But when I tried using the 1 micron filter with an apple + sugar + pineapple = cider I found the filter nearly eliminated any indication of the pineapple. SO, just something to keep in mind for those considering filtering.

For the purposes of kegging, as mentioned above by so many who have gone there before me, aging in primary (I don't even bother with secondary, really) seems to do enough to keep fermentation to an unnoticeable level IN THE KEG. By this, I mean no indications of over-carbonation if it sits in the keezer for a while, and no changing flavor profiles such as decreasing sweetness that would suggest fermentation is kicking back in. With the current batch I'm kegging I'll be bottling some from the keg; I'll leave these at room temp for a while to see if fermentation shows up in them.