Pasteurizing in a sanke sixth barrel

[Thanks_Yeasties]

I've done a bit of researching and read through many different techniques to pasteurize cider but have yet to see anyone talk of trying this technique. Seems most threads immediately get deflected to an alternative method.

My planned process:
Ferment cider dry (3 gallons), cold crash and rack into sanke sixth barrel keg with fresh juice to back sweeten.

Purge O2 (2 gallons head space) to prevent oxidation and disconnect CO2.

Put sanke in kettle with hot water from my sink up to the cider level in the keg, then heat on my burner until the water hits 160F, turn off and let cool.

Put back on CO2 and force carb.

Yes, I know there are campden and other chemical alternatives.
Yes, I know you could just chill the keg to put the yeast to sleep.
Yes, I am aware and have bottle pasteurized as described by pappers.

The cider would not be carbonated at all in the keg and the keg itself has a warning to not exceed 60 psi, would 160F still cider pressurize this above that level or even anywhere close? The only non-stainless steel piece on the keg is the rubber seal on the top of the valve which I believe would hold up.

I debated if leaving it connected so I could pull the pressure relief valve periodically would be a good idea but decided that would lead to a whole new set of pressure related questions about the coupler and such.

Has any one tried this method or something similar? Somewhere in that pappers post there is a whole slue of posts related to the pressure inside the bottles while at 160F but I don't have the patience to sift back through that whole thread, once was enough, ha.

 

[schwiz]

Probably most people wouldn't consider this because they don't have the equipment for sanke kegs. Doesn't seem like a bad idea though treating the keg as a giant bottle. I'm not sure 160F is needed. I think 15 minutes at 145F is enough but I would double check the FDA numbers.

 

[Thanks_Yeasties]

Good point, there is always the relation between temp and time to pasteurize, I guess I mention 160 because they use that for milk and its pasteurized in 15-20 seconds. However if that starts to push the pressure too close to the limit for my liking then I would definitely consider holding it 10-15 degrees lower for a bit longer as you mention.

 

[schwiz]

Aside from pressure I was also thinking a lower temp longer would have less effect on the flavor of the product as well.

 

[snowman_fs]

I have thought about trying the same.

My calcs were based on just the "air" headspace being the expansion factor as the liquid expansion is negligible. I seem to remember calculating a 3psi rise based on "ideal" gas law.

So nothing to worry about. I was more concerned with my soda kegs plastic and rubber base touching the bottom of the pot and melting. My plan was to put a trivet under it.

Only reason I didn't give it a try was that the cider was consumed too fast to be an issue anyway.

 

[Thanks_Yeasties]

My cider tends to go fast as well! So I'd like to make a few batches and have em kegged and ready to go.

Doing the math on the thermal expansion of air and how that translates to extra psi inside the keg is beyond me, but it seems if a glass bottle with carb'd up cider can handle that pressure, then a steel keg with flat cider in it could handle it much better.

 

[wilserbrewer]

my 2 cents.

1. The water bath and cider will not be the same temp, just cause the water bath is 160, the cider temp will lag behind.

2. I would just leave the spiral ring off the sanke keg to eliminate pressure build up during heating.

 

[Thanks_Yeasties]

my 2 cents.

1. The water bath and cider will not be the same temp, just cause the water bath is 160, the cider temp will lag behind.

2. I would just leave the spiral ring off the sanke keg to eliminate pressure build up during heating.

I like monies so the more 2 cents I collect on this the better!

1. You think it will lag behind because it is in a vessel even if they start out at the same temp and are heated together?

2. By leaving the ring off is this the only way to have a reliable pressure relief in case it did build the psi to high? Do you think it will hiss away a % of the alcohol in the cider?

 

[wilserbrewer]

I like monies so the more 2 cents I collect on this the better!

1. You think it will lag behind because it is in a vessel even if they start out at the same temp and are heated together?

2. By leaving the ring off is this the only way to have a reliable pressure relief in case it did build the psi to high? Do you think it will hiss away a % of the alcohol in the cider?

1. yes, just keep the bath at 160 for a reasonable time???
2. no, ethyl boils at 173 F

 

[Thanks_Yeasties]

I did end up giving this approach a try for anyone wondering. I put the cider in a sanke 1/6 barrel, with the post lose so it wouldn't build any pressure. I put that inside my kettle filled with a few gallons water. Then I kept my burner on low to slowly heat up the water to 165Fish where I left it at for a few minutes, then killed the heat and let it chill. I sealed and waited two days before pulling the pressure relief valve and nothing, so seems like it worked like a charm.

I would much rather do this then pasteurize in glass. Seems like ppl have good luck with that method but even when done correctly the glass can have flaws that can give out. Plus this was a one shot and done for 5 gallons.

Planning to do it again with the next batch and maybe I will do a write up on it with pictures.

 

[Archer]

Thanks, Yeasties, for sharing this! You are approaching "hero's of homebrew cider" status in my book. I am very interested in giving it a try as well, so I am looking forward to your follow up post with pictures. How confident are you that you got the requisite heat/time in your method to pastuerize? I'm no math whiz, so if anyone can chime in on that issue, I would greatly appreciate it.

 

[Thanks_Yeasties]

I don't have a long enough thermometer probe to reach down to the cider while heating it, so I went with the approach of slowing the heating process to allow the cider to keep up with the water outside the keg in the kettle. Maybe I can get a hold of one next time I try this, which may be a month from now.

I tried it on a caramel apple cider and it was starting to churn away once I back sweetened it before I tried the keg pasteurization.Afterwards, I sealed the keg once it cooled, brought it back inside and let it sit ambient for 2 days. I figure that would be long enough to build up even a minor amount of pressure considering all those new sugars in there and when I pulled the pressure relief valve I didn't have any pressure release, so I went ahead and force carbed.

Suppose next time I will do a much more thorough test but I was thirsty and it was ready to drink