Possible solution to the racking/oxygenation problem for secondary fermentation?

[GParkins]

This may sound stoopid, but what if you dropped a chunk of dry ice into your secondary fermenter just before racking? Wouldn't that displace all of the oxygen with CO2? How big a chunk would you need? Is dry ice even close to sterile? Would the cold spot where the dry ice landed stress a glass carboy?

 

[MaxStout]

It will displace some of it after it sublimes into gas. But it won't displace all of the air, as the CO2 will mix with it (gas diffusion). And yes, I would be concerned that the thermal shock from a -110F chunk of dry ice might crack a glass carboy.

Why not just purge as much air as you can using CO2 from a tank, then rack the beer into it? There would still be some oxygen left in there, but certainly a lot less. And many of us already have CO2 tanks.

 

[GParkins]

It will displace some of it after it sublimes into gas. But it won't displace all of the air, as the CO2 will mix with it (gas diffusion). And yes, I would be concerned that the thermal shock from a -110F chunk of dry ice might crack a glass carboy.

Why not just purge as much air as you can using CO2 from a tank, then rack the beer into it? There would still be some oxygen left in there, but certainly a lot less. And many of us already have CO2 tanks.

I don't have a CO2 tank, but my local grocery store carries dry ice. Oh, well...just a thought.

 

[lhommedieu]

Others on the forum have posted that slowly filling a carboy with CO2 is the way to go. "Slowly" means using 1-2 psi and can take several minutes. I use an orange carboy cap with the gas attached to a plastic racking cane to fill the carboy up from the bottom. Doing it slowly helps keep the CO2 and air in the carboy from mixing too much. It's much like treating the CO2 as if it were a liquid and slowly pouring it in so that it can seep up from the bottom. If you hold a match above the second vent on the cap and the match light flickers but stays lit, then you are probably still pushing mostly air out of the vent. If it goes out suddenly (without just running out of fuel), then you are probably pushing mostly CO2 out of the vent.

I do have a question, though, that just occurred to me. Is there a way to pull most of the air out of a carboy, before replacing it with CO2?

 

[GParkins]

It would mean putting the carboy under vacuum, which might pose some glass strength issues, not to mention the plumbing problem. I kind of like the carboy cap/racking cane/slow fill solution.

 

[Rcbandl]

Just pump some co2 into whatever container. co2 is heavier than air so it will sit on the bottom anyways, it may not eliminate O2, but it will minimize contact.

 

[doug293cz]

Just pump some co2 into whatever container. co2 is heavier than air so it will sit on the bottom anyways, it may not eliminate O2, but it will minimize contact.

No, that's not how gases behave. Heavier gas will interdiffuse and completely mix with lighter gas. It does take some time for homogenization to occur however. So, slowly filling CO2 from the bottom, to minimize air currents, will give a temporary CO2 layer. If you fill an entire container with CO2 this way, and then seal it up, you can get out most of the O2.

Brew on

 

[RM-MN]

Many of us avoid that question entirely by just leaving the beer in the primary until it is time to bottle. It seems that there is little to be gained by going to secondary except for adding fruit or long term aging and lots to lose if you oxidize your batch or get it infected.