How to: Balloon CO2 collection (Bruloonlock)

[Buffers brewery]

@Buffers brewery I have been thinking similar, but why not just get a 5 litre plastic container and fit a barbed pipe connector at the top and a barbed connector at the bottom, connect one with hose to your FV and one with hose to a blowoff bottle, this can be fitted at the start of fermentation if desired then will just work as normal but when cold crashing it cannot draw the water (or starsan) back into the FV but maintains a safe environment.

I'm looking at 2 options (yet to be tested). First, catch 500mls of CO2 from FV that can be sucked back during cold crashing.

The small jar is a liquid trap, the middle is filled with Starsan at the beginning but this is (should be) displaced to the last jar which, once filled, excess CO2 goes to the Starsan filled Keg. As I say, yet to be tested.

 

[Galena]

Please excuse the hasty sketch, but this is my idea, midway empty bottle can draw starsan from lower bottle without breaking the airlock and without sucking into the FV, it will naturally fill with CO2 as it will be used during fermentation

 

[Buffers brewery]

Please excuse the hasty sketch, but this is my idea, midway empty bottle can draw starsan from lower bottle without breaking the airlock and without sucking into the FV, it will naturally fill with CO2 as it will be used during fermentation
View attachment 33593

Great minds! Almost identical!

 

[Buffers brewery]

Might have to re-think my approach. Forgot to factor in the increased absorption rate of CO2 in water at lower temperatures.

Difference in solubility between 20 degrees C and 4 degrees C is 1.4 grms/litre. So 5 gallons/23 litres of beer potentially could absorb an extra 32 grms of CO2 during cold crashing. I make that around 16 litres of CO2 plus 0.5 litre due to the contraction of the gas. Am I over-thinking this?

 

[Edison]

FYI, last time I cold crashed in the FV from 19c down to 0.5c I used a full 40cm balloon filled from a CO2 cylinder. After almost a week at 0.5c the balloon was still over half full. This is for a 7(us)gal (26.5l) SS Chronical FV with a 20l batch in it. You’re not going to get a significant amount of CO2 absorption at atmospheric pressure IMO.

 

[Buffers brewery]

If my maths are right and we assume your 40cm balloon is a 40cm diameter sphere, I make that a little over 33 litres, so half full is 16.5 litres. Spooky

 

[foxy]

I’m starting to think about CO2 harvesting and looking at my options. I’ve read about purging corny kegs of Starsan (or similar) using CO2 prior to filling with beer. What are your thoughts on purging keg with CO2 as above, but not immediately before filling but during fermentation meaning the keg could have a Starsan/CO2 mix for up to 2 weeks? Starsan will maintain sanitation (that doesn’t sound right) and CO2 will keep O2 at bay?

The CO2 is also a sanitisor, purging a keg to be absolutely free of oxygen takes a lot of CO2 and at a high velocity. On a home brew scale just removing as much as possible is the best we can do, and that is enough. Oxygen is more a problem of commercials that's why they spend so much money on bottling lines etc.

 

[Edison]

@Buffers brewery I’ve just checked, it is a 45cm balloon, but a flat circular mylar one. When I connected it I hadn’t fully filled it fully to he point of putting any stress on it and when it was done, it had visibly deflated a little, but it was nowhere near what I would guess to be half full. I imagine it was more like less than 5 litres, but I have no way of measuring it, just a gut feeling.

 

[CD]

@Buffers brewery I’ve just checked, it is a 45cm balloon, but a flat circular mylar one. When I connected it I hadn’t fully filled it fully to he point of putting any stress on it and when it was done, it had visibly deflated a little, but it was nowhere near what I would guess to be half full. I imagine it was more like less than 5 litres, but I have no way of measuring it, just a gut feeling.

The Noddy balloons I use are marked 18” diameter, but measure 17”, the same as yours. I measured their capacity by connecting an empty one to a PB nearly full of water, inflating it full of CO2, then measuring how many pints of water I could draw before the balloon was empty and air started bubbling back through the tap. I got 23 1/3 pints out, or 13.25 litres. Hope this helps. (I was hoping to add photos of this but they are up in the clouds somewhere, and beyond my ken to retrieve them!)

 

[Buffers brewery]

Thanks for that info @Coffin Dodger . I’m going to increase the size of my jars from 500 mls to 5 litres for my brXperiment. Something to do
Out of interest, typically how many of your balloons can you fill from fermenting 5 gallons of brew?

 

[Spratt]

I’m starting to think about CO2 harvesting and looking at my options. I’ve read about purging corny kegs of Starsan (or similar) using CO2 prior to filling with beer. What are your thoughts on purging keg with CO2 as above, but not immediately before filling but during fermentation meaning the keg could have a Starsan/CO2 mix for up to 2 weeks? Starsan will maintain sanitation (that doesn’t sound right) and CO2 will keep O2 at bay?

I’m starting to think about CO2 harvesting and looking at my options. I’ve read about purging corny kegs of Starsan (or similar) using CO2 prior to filling with beer. What are your thoughts on purging keg with CO2 as above, but not immediately before filling but during fermentation meaning the keg could have a Starsan/CO2 mix for up to 2 weeks? Starsan will maintain sanitation (that doesn’t sound right) and CO2 will keep O2 at bay?

This is a work in progress for me at the moment. I have a lager in the Fermzilla in my brewfridge at the moment on day 6. I have collected two mylar balloons (36 inch ones) worth of CO2 from the brew so far which now seems to be quietening down. A couple of days ago, I filled my king keg to the brim with starsan, opened the bottom tap and started to drain out the starsan. It stopped running out almost immediately, which was when I then put my disconnect on the post fitted to the modified keg lid (the @Buffers brewery type lid). I hooked up one of the mylar balloons to the quick disconnect and the starsan started running again. It was slow, but eventually the keg was completely drained of starsan (and completely full of CO2). The mylar balloon still seemed pretty much full!

I expect to transfer my lager from my Fermzilla in 4 or 5 days time straight into the king keg. I can't think there will be a problem with there being about a week between sanitising and filling the keg as it is a closed vessel at the moment so no nasties can get in. We shall see...........

 

[Buffers brewery]

This is a work in progress for me at the moment. I have a lager in the Fermzilla in my brewfridge at the moment on day 6. I have collected two mylar balloons (36 inch ones) worth of CO2 from the brew so far which now seems to be quietening down. A couple of days ago, I filled my king keg to the brim with starsan, opened the bottom tap and started to drain out the starsan. It stopped running out almost immediately, which was when I then put my disconnect on the post fitted to the modified keg lid (the @Buffers brewery type lid). I hooked up one of the mylar balloons to the quick disconnect and the starsan started running again. It was slow, but eventually the keg was completely drained of starsan (and completely full of CO2). The mylar balloon still seemed pretty much full!

I expect to transfer my lager from my Fermzilla in 4 or 5 days time straight into the king keg. I can't think there will be a problem with there being about a week between sanitising and filling the keg as it is a closed vessel at the moment so no nasties can get in. We shall see...........

Hey @Spratt that sounds like what I’m trying to do but without the Fermzilla, just a regular FV bucket. Oh, and without the balloon

 

[Spratt]

The balloons I used are these

https://www.ebay.co.uk/itm/5x-36-Ho...397867&hash=item3b4574ff05:g:K50AAOSwvXNelIpr
which are pretty reasonable at less than a quid each.

Here was my first one on the way to getting full. As you can see gardening and brewing have to fight it out between themselves, though I fear the fork would win if it fell onto the balloon

 

[Buffers brewery]

I did a xBeeriment earlier this year to see if my FV was sufficiently air tight to generate enough pressure to displace water from said FV.
https://www.thehomebrewforum.co.uk/threads/closed-transfer-no-pump-no-c02-cylinder.89254/post-941934So my plan is to connect a small liquid trap to the FV gas out, then 2x5 litre jars in series (the first of which is filled with Starsan) and then to a Starsan filled KK. If it works () any liquid ejected from FV will be caught in the liquid trap. During fermentation, gas will displace starsan from first jar to second jar. Once the second jar is “full” the first jar will be full of CO2. The KK will then be connected so excess gas can displace the starsan from the KK and hopefully leave it full of CO2. KK can then be disconnected. During cold crash, CO2 should be sucked back from the first jar drawing starsan back from the second jar. The question is (apart from will it work? and why!?) will 5 litres of CO2 be enough for cold crashing. Hope to do a test run later this week to find out

 

[CD]

Thanks for that info @Coffin Dodger . I’m going to increase the size of my jars from 500 mls to 5 litres for my brXperiment. Something to do
Out of interest, typically how many of your balloons can you fill from fermenting 5 gallons of brew?

Managed it!

I don’t bother to try and collect all the CO2. I vent the PB slowly by sticking a pin behind the blow-off rubber, or by carefully slackening the cap, then when I am sure no fobbing is going to come over, change the cap to one my special adapter on it, and connect the Noddy balloon from the last PB I was drinking. It typically will be pretty empty, but will slowly fill over the next day or so to about a quarter full. If the beer is working properly I may need to use an S30 cylinder a couple of times.

It would be nice to collect all the CO2, but the cost of the gas I use is minimal. Also if beer fobs into the balloon it is a write-off.

 

[Buffers brewery]

So, my Xbeeriment was delayed a few days, but have just been testing first part of my “apparatus” .

Bottom left is FV1 full of water with pump connected to pump water up to FV2 front and centre. The fill speed is controlled by controller on the floor. The FV2 has lid fitted tight and 10mm pipe connects it to the small over-flow jar (tucked behind FV2). From the over-flow jar pipe goes to 5 litre paint kettle which is daisy-chained to the second paint kettle. The 2 kettles are connected using dip tubes that run to their bottom. Kettle 2 is vented to atmosphere.

Kettle 1 is filled (small air space) with water. Pump is turned on to pump water from FV1 to FV2 which displaces the air, simulating CO2 from fermentation. In turn, the air displaces the water from kettle 1 to kettle 2.

When all the water has been transferred, excess gas bubbles through the kettles and vents (phase 2 of the experiment is to connect the vent to a KK full of water to see if enough pressure can be developed to displace the water from the KK).

To simulate cold crashing, the water from FV2 is drained back to FV1 which creates a vacuum in FV2, drawing the gas out of kettle 1 back in to FV2 and the water from kettle 2 back to kettle 1.

Keeps me busy

 

[LED_ZEP]

Posted a link to this article in another thread but may be of interest here:

How Much CO2 Is Produced During Fermentation?

 

[Buffers brewery]

Posted a link to this article in another thread but may be of interest here:

Thanks for that @LED_ZEP . Very interesting. I’m sure there’s plenty of CO2 produced, I’m not sure how much is needed for the cold crash process. I started at 500mls just considering contraction due to temperature drop forgetting CO2 will be absorbed by the beer as the temperature drops. But how much? I’m guessing 5 litres but it’s probably more.

 

[DocAnna]

Thanks for that @LED_ZEP . Very interesting. I’m sure there’s plenty of CO2 produced, I’m not sure how much is needed for the cold crash process. I started at 500mls just considering contraction due to temperature drop forgetting CO2 will be absorbed by the beer as the temperature drops. But how much? I’m guessing 5 litres but it’s probably more.

The CO2 absorption due to cold crash depends on what the temperature change is and the volume of liquid. 20 litres dropped from 20 deg C to 1 deg C could absorb 0.8 volumes or about 16 litres. In practice I doubt that much is absorbed without agitation or pressurisation. The volume of gas contraction is actually tiny for that small temperature change and can be pretty much disregarded.

Anna

 

[Drunkula]

Out of interest, typically how many of your balloons can you fill from fermenting 5 gallons of brew?

Quick and dirty way is to times the expected abv per litre x 8.25. So 5% at 23 litres = 5 * 23 * 8.25 = about 950 litres of co2.

And when you've finished a keg it'll still have around 2 or so volumes of co2 in it so use that to purge a clean keg rather than wasting it.