[Mjogg11]

I apologize if this has been posted somewhere else in the forum.  I’m new to the Homebrewers Association and tried to search. 

My question is whether anyone uses a corny keg for secondary fermentation and dry hopping?  I have an Zombie Dust clone in a 7 gallon stainless steel fermenter.  My goal is to minimize oxygen exposure on the transfer to secondary and was wondering if anyone ever transfers from the fermenter directly into the keg to avoid oxygen.  My guess was that I would have to sanitize the keg and fill with some amount of CO2 to remove the oxygen and then push the beer into the keg through the “beer out” fitting. 

Is this possible or recommended?  I generally dry-hop in a carboy but don’t want the oxygen in the headspace and also don’t want to water down the beer to reduce the head space.  I have a little over 5 gallons of wort and a 6 gallon carboy.

Thank you in advance!

[charlie]

I don't think the 5 gal corny is going to be good for dry hopping. If you use pellet hops they're going to fall to the bottom and block the outlet dip tube, and you'll have to rack the finished beer out with your racking cane. If you use leaf hops I don't feel that swirling that small a diameter vessel is going to adequately mix them up. Either way I think it's going to be more trouble than it's worth.

Charlie

[BrewBama]

I know what you mean about searching on this forum. It seems all the search results are years old when I know the topic has been discussed more recently.

As far as your question about closed transferring to a keg direct from the fermenter in an effort to reduce oxygen exposure, here’s what I do:

1. Fill the keg with no foam sanitizer as much as possible and install the lid.  Top off completely by using a bottling bucket with a spigot. Run the hose from the spigot to the out post using a black beer disconnect. Ensure the keg is tilted so the gas in post is the highest point. Attach a spare grey gas QD. Open the spigot until sanitizer comes out the gas QD. The keg is now full of sanitizer.

2. Use the same hose you filled the keg with but close the spigot, detach it from the bottling bucket spigot, and place the lose end in the bottling bucket. Pressurize the keg with 2-3 psi from a CO2 tank.  Leave the QD attached to the gas in post to push out the sanitizer. Install the black beer QD. Once CO2 begins to bubble in the now full bucket of sanitizer disconnect the black QD. Disconnect the gas in QD from the keg.

3. Turn the keg upside down by turning it towards the gas in post with the gas in post at the lowest point (slightly tilted). Using a spare gas in grey QD, install the QD to allow residual sanitizer to escape. (Shortened gas in dip tube helps with getting all the residual out) Do not allow all the CO2 to escape.

4. Using the same hose you used to fill and drain the keg, attach the black QD onto the liquid out post and while gas is escaping quickly attach it to the spigot of your fermenter. Tighten hose clamp. You just purged the line with CO2.

5. Attach a hose to the spare grey QD and install it on the gas in post of your purged keg. As CO2 is escaping attach it to the top of your fermenter. You just purged the line with CO2 and created a pretty darn close oxygen free closed loop.

6. Open drain on the fermenter, have a beer. Wait until beer comes out the gas in line. I like to lay my keg on its side with the gas in post high for this. You now have a full keg of beer that displaced the CO2 in the keg by pushing it into the fermenter.

7. Once full, with keg upright and level, apply a small amount of pressure to the keg and a tap. Drain a bit of beer until you no longer hear CO2 bubbling in beer. You just created CO2 filled headspace.

Hope this helps.


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[narvin]

These are nice for dry hopping with pellets in the keg:

https://www.utahbiodieselsupply.com/brewingfilters.php#cornydryhopper

[hopfenundmalz]

BrewBama gave a very nice run down.

I pressurize my conical with 2 PSI to help push the beer into the keg, that helps speed things up.

How do you know when the keg is full? Use a scale, the keg is  ~10 lbs, 5 gallons of beer is 40, so I fill to 50 Lbs.

If you add hops to the keg you are introducing O2 when the lid is opened. Two things you can try. Seal the lid, repeatedly purge the head space with 30 PSI CO2, I do 13 time to drop the O2 to a theoretical 1 ppb. You can also add the hops before the beer, and run CO2 at 1 PSI into the beer out while venting out the gas in with an air lock. That low pressure will minimize mixing in the keg. How long? Not sure.

[Mjogg11]

Thank you everyone!  This is incredibly helpful.  BrewBama-  Thank you for such a detailed response.  It is extremely helpful.  Narvin-  I actually purchased one of the 11.5” cylinders yesterday at my local brewer supply store.

I talked to the owner of the brewer supply store and he shared that he fills the keg with CO2, purging the oxygen out repeatedly.  He then fills the keg from the fermenter through the top, much the same way you would fill a carboy.  He said that since CO2 is heavier than oxygen the liquid displaces CO2 which displaces O2.  Once full he purges any remaining O2 with CO2.  He said that it does create a little exposure to O2 but not enough that he has ever noticed a difference.  In his estimation for home brewing purposes it is much easier than creating a new jumper cable to adjust for the size difference between the fermenters out and keg in. 

In his opinion the thing that he thought would make a big difference is to then transfer from the secondary keg to a third for clarifying and carbonating.  He suggested that rather than focus on zero oxygen exposure the move from secondary to tertiary would possibly create a clearer and more pleasant beer. 

Thanks again for all of your help!  Because of the kind and thoughtful responses I’m about to convert my trial membership into an annual one.  Thanks for helping out a new brewer!  Cheers!

[denny]

Thank you everyone!  This is incredibly helpful.  BrewBama-  Thank you for such a detailed response.  It is extremely helpful.  Narvin-  I actually purchased one of the 11.5” cylinders yesterday at my local brewer supply store.

I talked to the owner of the brewer supply store and he shared that he fills the keg with CO2, purging the oxygen out repeatedly.  He then fills the keg from the fermenter through the top, much the same way you would fill a carboy.  He said that since CO2 is heavier than oxygen the liquid displaces CO2 which displaces O2.  Once full he purges any remaining O2 with CO2.  He said that it does create a little exposure to O2 but not enough that he has ever noticed a difference.  In his estimation for home brewing purposes it is much easier than creating a new jumper cable to adjust for the size difference between the fermenters out and keg in. 

In his opinion the thing that he thought would make a big difference is to then transfer from the secondary keg to a third for clarifying and carbonating.  He suggested that rather than focus on zero oxygen exposure the move from secondary to tertiary would possibly create a clearer and more pleasant beer. 

Thanks again for all of your help!  Because of the kind and thoughtful responses I’m about to convert my trial membership into an annual one.  Thanks for helping out a new brewer!  Cheers!

The "CO2 is heavier than air" thing is a myth that refuses to die. Gasses mix.  But other than that, that, I do anout the same method.  Except no secondary is necessary.  I go from fermenter to serving keg.

[hopfenundmalz]

Thank you everyone!  This is incredibly helpful.  BrewBama-  Thank you for such a detailed response.  It is extremely helpful.  Narvin-  I actually purchased one of the 11.5” cylinders yesterday at my local brewer supply store.

I talked to the owner of the brewer supply store and he shared that he fills the keg with CO2, purging the oxygen out repeatedly.  He then fills the keg from the fermenter through the top, much the same way you would fill a carboy.  He said that since CO2 is heavier than oxygen the liquid displaces CO2 which displaces O2.  Once full he purges any remaining O2 with CO2.  He said that it does create a little exposure to O2 but not enough that he has ever noticed a difference.  In his estimation for home brewing purposes it is much easier than creating a new jumper cable to adjust for the size difference between the fermenters out and keg in. 

In his opinion the thing that he thought would make a big difference is to then transfer from the secondary keg to a third for clarifying and carbonating.  He suggested that rather than focus on zero oxygen exposure the move from secondary to tertiary would possibly create a clearer and more pleasant beer. 

Thanks again for all of your help!  Because of the kind and thoughtful responses I’m about to convert my trial membership into an annual one.  Thanks for helping out a new brewer!  Cheers!

The "CO2 is heavier than air" thing is a myth that refuses to die. Gasses mix.  But other than that, that, I do anout the same method.  Except no secondary is necessary.  I go from fermenter to serving keg.

I agree, but let me ramble on a bit.

CO2 ist heavier than air and will pool. But it mixes with the atmosphere immediately, but total equilibrium takes time. . In industrial settings, confined spaces are a safety concern. Deaths happen when workers enter those spaces and get asphyxiated.

Here is the thing most don't know. If the atmosphere reaches 10% CO2 it is lethal. There is still ~19% O2 in the mix. We want very low parts per billion O2, not double digits percentage wise.

Pressurizing the keg and venting a couple of times will not do the job. To get to a low O2 level you need to pressurize at 30 PSI and vent 13 times. That wastes CO2 compared to filling with sanitizer and pushing it out with CO2.

A few years back I remember a YouTube video making the rounds on Homebrew forums. It showed a candle in an empty glass aquarium. A container that had been filled with CO2 was poured in, and the candle went out. From an industrial safety video on confined spaces, a flame was extinguished when there atmosphere was reduced to <19% O2. Just because the candle went out, it doesn't mean that there was no O2, just not enough.

One needs to do more than squirt some CO2 in to eliminate O2.

[BrewBama]

One needs to do more than squirt some CO2 in to eliminate O2.

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[brian_welch]

I do the closed transfer as described by BrewBama but that still doesn't answer how to dry hop without exposing the beer to oxygen (without purging a keg 13 times which I refuse to do).  The only solution I have used is to dry hop during the final stages of fermentation and hope that the active yeast will scavenge the oxygen introduced. Which is what I will be doing probably tomorrow to a best bitter I brewed on Saturday.

[Richard]

The "CO2 is heavier than air" thing is a myth that refuses to die. Gasses mix.  But other than that, that, I do anout the same method.  Except no secondary is necessary.  I go from fermenter to serving keg.

"CO2 is heavier than air" is not a myth ... it is a scientific fact, and ignoring it can have deadly consequences as Jeff points out. The problem is that it is misunderstood and misinterpreted by some homebrewers to mean that CO2 will displace all oxygen instantly. In fact, the displacement will depend on many factors, including the shape of the vessel and the relative temperatures of the two gasses.

"Gasses mix" is another scientific fact which is also misunderstood and misinterpreted by some homebrewers to think it means that two gases put next to each other will reach their equilibrium mixture instantly. In fact, the time required to reach equilibrium (if it is ever reached) depends on many factors, including the shape of the vessel and the relative temperatures of the two gasses.

"Oxygen exposure results in oxidation" is another scientific fact that is misunderstood and misinterpreted by some homebrewers who think it means that any exposure to oxygen will immediately result in oxidation-related staling products. The fact is that the time it takes for oxygen exposure to result in oxidation depends on many factors, including the shape of the vessel, the temperature of the beer and whether there is competition for the oxygen (i.e. yeast or oxygen scavenging chemicals).

We see the first two discussed frequently, but I don't recall seeing much discussion of the third point.

[BrewBama]

I do the closed transfer as described by BrewBama but that still doesn't answer how to dry hop without exposing the beer to oxygen (without purging a keg 13 times which I refuse to do).  The only solution I have used is to dry hop during the final stages of fermentation and hope that the active yeast will scavenge the oxygen introduced. Which is what I will be doing probably tomorrow to a best bitter I brewed on Saturday.

Unfortunately, it’s nearly impossible to truly dry hop after closed transfer without introducing O2. There are some entrepreneurial minds on HBT that have tried to tackle the problem every way from Sunday.

I have used late additions, whirlpool and hop stands, separately and in combination, to try to emulate the effect.

I have seen one brewer close transfer, then push the beer thru a Randal into another keg which looks like it might work. But he didn’t solve the problem of days long contact with the hops.

Your idea to dry hop in the fermenter is probably the best one. If you do it near the very end, when the yeast are still active they might consume the O2 introduced by opening the FV.


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[denny]

The "CO2 is heavier than air" thing is a myth that refuses to die. Gasses mix.  But other than that, that, I do anout the same method.  Except no secondary is necessary.  I go from fermenter to serving keg.

"CO2 is heavier than air" is not a myth ... it is a scientific fact, and ignoring it can have deadly consequences as Jeff points out. The problem is that it is misunderstood and misinterpreted by some homebrewers to mean that CO2 will displace all oxygen instantly. In fact, the displacement will depend on many factors, including the shape of the vessel and the relative temperatures of the two gasses.

"Gasses mix" is another scientific fact which is also misunderstood and misinterpreted by some homebrewers to think it means that two gases put next to each other will reach their equilibrium mixture instantly. In fact, the time required to reach equilibrium (if it is ever reached) depends on many factors, including the shape of the vessel and the relative temperatures of the two gasses.

"Oxygen exposure results in oxidation" is another scientific fact that is misunderstood and misinterpreted by some homebrewers who think it means that any exposure to oxygen will immediately result in oxidation-related staling products. The fact is that the time it takes for oxygen exposure to result in oxidation depends on many factors, including the shape of the vessel, the temperature of the beer and whether there is competition for the oxygen (i.e. yeast or oxygen scavenging chemicals).

We see the first two discussed frequently, but I don't recall seeing much discussion of the third point.

Yes, you are correct and I was not specific enough.

[hopfenundmalz]

I have used a hop rocket loaded with whole cone hops tomtransfer the beer from keg to keg, domit mor than once for full effect. Everything is purged with CO2. It works, the drawbadk is time, and limited whole cone hops availability.

I have added pellets to kegs. If if is full you don't use too much CO2 purging  the headspace 13 times at 30 PSI.

Another technique would be to have a purged keg, open and add a bad of hops quicly. Then slowly add CO2 through the out post at 1 psi, with the in post hooked to an water bath for an airlock. I haven't  tried this. It would take some time, which i have not determined.

[mainebrewer]

When I dry hop;
I purge a keg by filling it with sanitizer and then pushing the sanitizer out with CO2,
Open the keg and drop in the dry hops,
Attach the keg "beer in" connection to my fermenter,
Attach a tube to the "gas in" connection and run it into a container of water,
Once fermentation has reached the target, I do a closed transfer from the fermenter to the keg.

My assumption is that the fermentation will (and does) fill the keg with CO2 and hopefully purge out the O2 that was admitted by opening the keg to place the hops and the CO2 that is contained in the hops themselves. I don't have any data to back this up but it seems logical and doesn't take much time to set up. I bag my hops and use a Clear Beer floating dip tube.