Closed Transfer - No pump, no C02 Cylinder

[ssashton]

I just wanted to share my recent method for doing closed transfers to keep oxygen away from the brew.

It may be obvious and everyone already knows, but all methods I've seen used on YouTube use a C02 cylinder to purge the new vessel and force the beer over, or use a pump after purging.

What I have been doing is simple really.

I ferment in one of the cheap-ish plastic kegs / pressure barrels. They hold about 10PSI before the pressure starts to release via the rubber band thing that acts as an over-pressure port. In the top I fitted a Shrader valve, like a tyre has. I connect the plastic fermentation barrel to the keg I plan to prime and condition in. After about 24-hours the fermentation has generated quite a bit of C02 and pressure in both vessels. I purge a bit of the gas from the second vessel to remove (I hope) oxygen and let it finish out.

Fermentation

To transfer oxygen-free to the keg all I do is place the plastic fermentation barrel high up and let gravity draw the beer in to the conditioning keg via a tube from the bottom tap / port. If the liquid tube was the only connection this would not work becasue the liquid will stop flowing when the pressure in the keg increases, but I keep the gas line connected between the two vessels. This way as the beer flows in to the conditioning keg, gas flows out to the plastic fermentation barrel. No need to keep releasing C02 from the keg as you fill it, the over-all pressure remains at the same across the two vessels, about 10PSI.

Transfer

 

[ssashton]

I still wish I had a way to store the C02 for later use. I do have a diaphragm pump and it allows me to pump C02 from one vessel to another, but only with a differential of about 5PSI.

 

[Leard]

How do you ferment in those barrels? I have one but there's no way for air to escape from the top valve thing. How do you use an airlock on them?

Currently I ferment in a plastic bucket with a tap and a normal airlock on. When it's time to transfer to keg I attach a tube between the tap on the fermenter and the beer out disconnect of the keg. Then I open the tap on the fermenter and let gravity do it's work. I have to open up the PRV to allow CO2 to escape. However I don't think this method allows any amount of oxygen in to worry about. The CO2 from the beer in the keg forces out any oxygen through the PRV and no oxygen can enter it since CO2 is escaping from it.

 

[JockyBrewer]

You can also store CO2 from fermentation in a mylar balloon

(Please excuse the grotty paper towel catching drips from the tap I didn't check for leaks before filling the fermenter)

When you cold crash it sucks the CO2 back in instead of air, and you can use it to fill the headspace when transferring out of the fermenter too.

 

[Leard]

I've been considering this mylar balloon method so I can cold crash without risk of oxidation. How large a balloon do you use? And how do you make sure it's sealed to the tubing?

 

[Gerryjo]

I just wanted to share my recent method for doing closed transfers to keep oxygen away from the brew.

It may be obvious and everyone already knows, but all methods I've seen used on YouTube use a C02 cylinder to purge the new vessel and force the beer over, or use a pump after purging.

What I have been doing is simple really.

I ferment in one of the cheap-ish plastic kegs / pressure barrels. They hold about 10PSI before the pressure starts to release via the rubber band thing that acts as an over-pressure port. In the top I fitted a Shrader valve, like a tyre has. I connect the plastic fermentation barrel to the keg I plan to prime and condition in. After about 24-hours the fermentation has generated quite a bit of C02 and pressure in both vessels. I purge a bit of the gas from the second vessel to remove (I hope) oxygen and let it finish out.

View attachment 30916
Fermentation

To transfer oxygen-free to the keg all I do is place the plastic fermentation barrel high up and let gravity draw the beer in to the conditioning keg via a tube from the bottom tap / port. If the liquid tube was the only connection this would not work becasue the liquid will stop flowing when the pressure in the keg increases, but I keep the gas line connected between the two vessels. This way as the beer flows in to the conditioning keg, gas flows out to the plastic fermentation barrel. No need to keep releasing C02 from the keg as you fill it, the over-all pressure remains at the same across the two vessels, about 10PSI.

View attachment 30917
Transfer

Quite a setup.

 

[AnimatedGIF]

View attachment 30916


View attachment 30917

I like your fireplace.

 

[JockyBrewer]

I've been considering this mylar balloon method so I can cold crash without risk of oxidation. How large a balloon do you use? And how do you make sure it's sealed to the tubing?

These are the ones I got: 22 Inch 4D Balloons Large Foil Balloons Sphere Foil Balloons 4D Round Balloons for Birthday Wedding Baby Shower Party Decors (Silver):Amazon.co.uk:Toys & Games
22 inches across, and they're too big to get anything like fully inflated in my brew space. So maybe get something smaller.

I just seal it around a piece of rigid plastic tubing (3/8" beer line) with some cable ties, and the silicone tube I use for blow off fits over that nicely.

 

[ssashton]

How do you ferment in those barrels? I have one but there's no way for air to escape from the top valve thing. How do you use an airlock on them?

The brass fitting where you put small C02 cylinders actually has a pressure release. You can see that white band? That is an elastic band covering a hole. If the pressure is too high (>10psi) it squeaks out past the rubber band.

I drilled a hole in the top and added a schrader valve so I can port the C02 to my secondary keg.

Fermenting under pressure changes how the yeast produces off flavours and it's reported to be cleaner tasting. Popular for doing larger.

The problem with using a balloon is that I want to be able pressurise stuff, but you can't exactly squeeze the balloon in to a keg at 10psi.

If you fill a keg with C02, how long does it take for the air to settle at the top?

 

[Buffers brewery]

If you fill a keg with C02, how long does it take for the air to settle at the top?

Answer=never. The longer you leave it the more homogeneous the gas mixture will be.

 

[Buffers brewery]

Sorry, my OCD has got the better of me.
Depending on the head space in your FPB that is filled with air, that is pushed out first at the beginning of fermentation, so you don’t want to collect that if you want to be O2 free. You could test the gas from your FPB for CO2 by bubbling it through limewater before connecting to your corny, limewater goes white/milky in the presence of CO2.
Your corny is full of air at the beginning so as the CO2 is added it will become a mixture and will not stratify as cleanly as you think. I believe the common practice to eliminate the air from a corny is to fill it with water and purge it out using CO2. Have you tried doing that with the CO2 from your FPB? I guess the height of a corny is about 2 feet? If you’re generating 10 psi (that’s +20 feet of water pressure) in your FPB that should be more than enough to push the water out of your corny (depending on any back pressure created by plumbing connections). That way you will have a rich CO2 source.

 

[Spratt]

Sorry, my OCD has got the better of me.
Depending on the head space in your FPB that is filled with air, that is pushed out first at the beginning of fermentation, so you don’t want to collect that if you want to be O2 free. You could test the gas from your FPB for CO2 by bubbling it through limewater before connecting to your corny, limewater goes white/milky in the presence of CO2.
Your corny is full of air at the beginning so as the CO2 is added it will become a mixture and will not stratify as cleanly as you think. I believe the common practice to eliminate the air from a corny is to fill it with water and purge it out using CO2. Have you tried doing that with the CO2 from your FPB? I guess the height of a corny is about 2 feet? If you’re generating 10 psi (that’s +20 feet of water pressure) in your FPB that should be more than enough to push the water out of your corny (depending on any back pressure created by plumbing connections). That way you will have a rich CO2 source.

There's an interesting post by Marshall Schott on Brulosophy about all of this. He says "Curious as to just how much pressure is needed to push liquid out of one keg and into another, I tested it out with a tank of CO2 and found it’s around 1.5 psi".

The whole article is here

http://brulosophy.com/2020/07/09/using-co2-from-fermentation-to-purge-serving-kegs-do-it-yourself/
I have to say I think the OP's system shown above is a very neat solution albeit with the caveats you list above. I think you must have paid more attention in your chemistry lessons than I did, to remember that old trick of CO2 and limewater! Very neat.

 

[Buffers brewery]

I think you must have paid more attention in your chemistry lessons than I did, to remember that old trick of CO2 and limewater!

I’ve reached that golden age that I can remember stuff from +50 years ago but don’t know what I did last week!

 

[Buffers brewery]

Just out of interest, and spurred on by @ssashton OP I did a little experiment, or is it an xBmt? I wondered if a standard FV could develop enough pressure to displace water from a similar FV. As it happens one of my FVs lid is fitted with a HB valve so I can flush with CO2, so I partially filled said FV with water, fashioned a length of 10mm copper tube to make a straw that fitted through the trap hole grommet and reached to the bottom of the bucket. Secured the lid in place and gently squirted some CO2 in and this is what happened....

Admittedly the gas supply was constant but the xBmt showed that in theory, you don’t need a PFV to develop enough pressure to displace water from a filled container in order to collect CO2. Next xBmt is, when I next do a brew, to daisy chain my 2 FVs to see if there is sufficient seal on the 2 lids to generate enough pressure to displace the water from the second FV. Thanks for the inspiration @ssashton

 

[ssashton]

This is great! Sorry I didn't reply sooner.

Thinking about the flushing air with CO2 and how the two might mix...

I do recall that one definition a gas is that it expands to fill the container. So I think this is why Bufferes said the CO2 and air will mix?

However there are clear demonstrations of pure CO2 being 'poured' like a liquid and displacing air because it's heavier. You remember the old experiment pouring CO2 from a glass on to a candle in a bowel and it goes out?

Therefore I think that when you add CO2 to a vessel, it will at first settle to the bottom, then over time spread out and mix with the air.

So if I use a pure CO2 source (either bottled or re-captured) to flush a corny, it makes sense to me to give it maybe 30 seconds to fall to the bottom and then open the purge valve on top to let air out.

Regarding purging a non-pressure vessel. I think there is another way to do it if you have CO2 captured in a balloon. Fill the vessle with water and connect the CO2 source on top. Open a tap to drain the water out the bottom. As gravity pulls the water out the CO2 will be drawn in.

It does work very well fermenting in these plastic pressure barrels though, I recommend it for anyone who wants to try pressure fermentation. Recently even my cellar is 22C. I'm doing 'House Pale by John Finch' right now and says to ferment at 19C, but I don't worry too much because under pressure you can apparently get away with higher temps. I pitched the yeast on Saturday evening, OG1045. I'ts now at 1014.

 

[Spratt]

That's a very neat idea about filling the keg with water to get the CO2 drawn in from a balloon. My problem at the moment is keeping the gas in the balloon, when it comes off the Fermzilla!

 

[Buffers brewery]

It’s all to do with speed. The demonstration works because he has a cup of CO2 which was generated “quickly” by mixing two chemicals. The CO2 was generated in sufficient quantities and fast enough to push the air in the cup out. The CO2 was then transferred “quickly” to another cup, displacing it’s air. Then, the CO2 in the last cup is used “quickly” to extinguish a candle. If he had slowed the experiment down and left things a while between transfers, the CO2 would have mixed with the surrounding air and eventually, if left long enough, would disappear and form a mixture the same as the surrounding air.

IMO, the displacement of water using CO2 is the most efficient way of creating an O2 free space.