Closed Transfer in Glass Carboy- Am I thinking about this right?

[HutBrew]

A) is a 1/4” barb x MFL
B) is a MFL washer
C) is a 3/8” barb x FFL

I saw a YouTube video from Brew n BBQ about closed transfers using a carboy, and created this rough sketch depicting my interpretation.

I wanted to know if anyone here has done this before, your successes, and if you believe this sort of setup/diagram would be feasible or work?

I want to improve my techniques, without breaking the bank. As much as Unitanks, stainless mash tuns and HLTs are awesome as hell, I’m going to have to make due with cooler HLT&MTs. However, I do wish to upgrade from plastic bucket fermentors, and wanted to get into closed transfer, hence the diagram.

Please share any thoughts!
Thanks HBT community!

 

[Dr_Jeff]

I built a couple similar to that but put a gas pinlock plug on the top of the carboy cap to be able to more easily hook it up, also used a SS racking cane.

 

[madscientist451]

Yeah it will work, but you'd be better off scaling your batches back to 4.5 gallons and just fermenting in a corny keg with the dip tube shortened. No worries about too much pressure or that carboy cap leaking. I've moved to keg fermenting for all my IPA's and am glad I did.

 

[HutBrew]

Dr Jeff-
I forgot to mention I had a stainless racking cane in mind
I’ll have to look into plugs- but for ball lock, as my kegs are all BL
Thanks for your feedback!

 

[HutBrew]

Mad scientist-
I’ll consider keg fermenting, if I can convince SWMBO to let me buy more kegs that is…
Thanks for the advice!

 

[Jayjay1976]

I think your diagram needs a Liger to be taken seriously.

 

[VikeMan]

You're going to need a spunding valve to relieve pressure in the keg while it's filling, or (less ideally) hold the keg's own PRV open.

I used to do closed transfers with glass carboys. To be honest, it always made me a little nervous, especially if anything clogged the racking cane and required an increase in pressure to dislodge it. It's much safer with a SS conical. And more foolproof from a low oxygen standpoint.

 

[HutBrew]

VikeMan-
I was worried someone would bring up a point like this.
I’m really hoping not to have to invest in an expensive fermentor, but thanks for your feedback

 

[HutBrew]

mad scientist-
Something like this, connected to an F NPT x 1/4” barb?

 

[VikeMan]

Have you had a look at the thread on closed transfers with a converted Fermonster (platic carboy)?
https://www.homebrewtalk.com/thread...lete-closed-transfer-system-for-cheap.680992/

 

[Deadalus]

I just built this recently and have done 2 transfers. That's 3/8" tubing, 3/8" barb x 1/4 mfl adapter, and a soda carbonation cap which has a 1/4" barb. The transfer hose also has that same adapter on both ends. I'm not particularly fond of the orange carboy caps but the one I am using is especially crummy and doesn't sit well. I had a little trouble getting this to work because I had used the racking cane to punch a hole in some silicon tubing and thought I had gotten the piece out and didn't and I had a partial blockage. I bled the PRV while test running this but I have the parts picked out for a spunding valve. I may just buy one though because it's difficult to get all the parts from one place and shipping eats up the little bit of savings.


No teflon on flare fittings.

 

[DarrellQ]

Yeah it will work, but you'd be better off scaling your batches back to 4.5 gallons and just fermenting in a corny keg with the dip tube shortened. No worries about too much pressure or that carboy cap leaking. I've moved to keg fermenting for all my IPA's and am glad I did.

Do you transfer to another keg after fermentation? Rather than a shortened dip tube, wouldn't a floating dip tube work?

 

[Dr_Jeff]

I used to do closed transfers with glass carboys. To be honest, it always made me a little nervous, especially if anything clogged the racking cane and required an increase in pressure to dislodge it.

Each time I have used a bit too much pressure, the orange carboy cap would pop off, with a resounding POP

 

[GrowleyMonster]

I use the plastic Big Mouth Bubblers as fermenters, with spigots installed near the bottom but high enough to not suck up too much trub. My kegs are full of CO2 from purging the weak star san solution that I typically leave in the keg for a week or whatever after cleaning. My fermenter is higher than the keg, which is standing on the floor. First I bleed off any pressure in the keg. Next, I run a hose from the spigot to the keg's beer connection, and another hose from the keg's gas connection to the stopper in the BMB lid. I open the spigot and gravity pulls the beer down into the keg, which pushes CO2 into the top of the fermenter. Closed loop. Not my idea. I learned that here on this forum.

With no spigot, working with a racking cane, you would have to establish a siphon to do this in a closed loop. Installing a spigot in a plastic fermenter is much easier.

 

[madscientist451]

Sure, a floating dip tube would work, but it was just easier for me to cut one off. After fermentation is done, I do a closed transfer to a serving keg.

 

[Deadalus]

Each time I have used a bit too much pressure, the orange carboy cap would pop off, with a resounding POP

That's exactly what happened with my partial blockage. Those orange caps aren't particularly tight holding. The one I was using is slightly deformed too from being squished in a drawer. I don't use them for fermenting anymore. They are a tight fit in my ferm chambers with an airlock and the slightest bump would push them off the neck. I recently took the thermowell out of the only one I was still using.

 

[Bilsch]

For reference..
1 psi in a 5 gallon carboy is exerting a force of 800 lbs on the internal surface.
2 psi would be 1600 pounds and so forth.
Just something to consider.

 

[Dr_Jeff]

So, I was likely transferring at 8-10psi, possibly as low as 6.

 

[Deadalus]

For reference..
1 psi in a 5 gallon carboy is exerting a force of 800 lbs on the internal surface.
2 psi would be 1600 pounds and so forth.
Just something to consider.

Can you please elaborate? 2 psi is 2 pounds of force per square inch.

 

[Bilsch]

Can you please elaborate? 2 psi is 2 pounds of force per square inch.

Certainly.

A 5 gallon glass carboy is 10.5” in diameter and 19.5” tall. So to calculate the inner surface area we need the circumference which is roughly 31.4 inches around. Then multiply that figure by the height of 19.5” and you get 612.2 square inches of surface area for the sides. The area of the top is about 86 sq/in so multiply that by two for top and bottom and you get 172 sq/in. So in total 784 sq/in for the inside of a five gallon carboy.
Note: in my last quick calculation I neglected to subtract the wall thickness which is updated above.

Therefore if you add 1 pound per square inch of pressure you must multiply that by the surface area, in this case 784 sq/in. This gives you a force pushing out of 784 pounds. Multiply that by the 8 to 10 psi mentioned in a previous post and you get between 6272 and 7840 pounds of force.

 

[hotbeer]

Why not get a suction pump and pull a vacuum on the keg?

I'd think the carboy will withstand external pressure better than internal pressure. And probably less glass flying all over if it does implode as opposed to explode.

You can fill up a balloon with CO2 and hook it to a line on the carboy so it can replace the volume of the beer being drawn out.

 

[Deadalus]

Certainly.

A 5 gallon glass carboy is 10.5” in diameter and 19.5” tall. So to calculate the inner surface area we need the circumference which is roughly 31.4 inches around. Then multiply that figure by the height of 19.5” and you get 612.2 square inches of surface area for the sides. The area of the top is about 86 sq/in so multiply that by two for top and bottom and you get 172 sq/in. So in total 784 sq/in for the inside of a five gallon carboy.
Note: in my last quick calculation I neglected to subtract the wall thickness which is updated above.

Therefore if you add 1 pound per square inch of pressure you must multiply that by the surface area, in this case 784 sq/in. This gives you a force pushing out of 784 pounds. Multiply that by the 8 to 10 psi mentioned in a previous post and you get between 6272 and 7840 pounds of force.

That's what I thought you might be doing. It's pounds divided by square inches. That can be converted to pounds per square ft if you like by multiplying by the value of one, but instead of using 1, you use 144 sq in/1 sq ft as that is also like multiplying by one. You can calculate the total internal surface area and figure out the force, but that force is for the whole area. But in all cases the pressure is 2 pounds per square inch, not 2 pounds by itself.

If you blow 2 psi of air at your skin of your arm, your arm won't break, but your arm hairs might wiggle some. Your skin can withstand about 1000 psi and although glass strength varies that's also the suggested value for regular glass.

 

[Bilsch]

I'd think the carboy will withstand external pressure better than internal pressure. And probably less glass flying all over if it does implode as opposed to explode.

It seems like it might but sadly that that is not the case. When the implosion happens the glass particles accelerate toward the center but then just keep going. The only difference is you get hit with the shards from the far side of the carboy instead of the near side. Obviously this worst case assumes the liquid is not completely full. You are in more danger the lower the level gets during the transfer.

 

[Bilsch]

That's what I thought you might be doing. It's pounds divided by square inches. That can be converted to pounds per square ft if you like by multiplying by the value of one, but instead of using 1, you use 144 sq in/1 sq ft as that is also like multiplying by one. You can calculate the total internal surface area and figure out the force, but that force is for the whole area. But in all cases the pressure is 2 pounds per square inch, not 2 pounds by itself.

It is most certainly NOT divided by square inches but multiplied. You can convert to any units you'd like but the physics remain the same. And this is a good thing because in your world hydraulics would not work, that and we all would be dead.

In your example of air blown against your skin, you are not feeling pressure but simply the force of the mass of the air times it's velocity. The pressure drops instantly after the air escapes the nozzle by immediately expanding to atmospheric pressure.

 

[hotbeer]

It seems like it might but sadly that that is not the case. When the implosion happens the glass particles accelerate toward the center but then just keep going. The only difference is you get hit with the shards from the far side of the carboy instead of the near side. Obviously this worst case assumes the liquid is not completely full. You are in more danger the lower the level gets during the transfer.

But you are sort of imagining a ideal theoretical yield to your carboy implosion. In reality, I believe that the failure will let air in before the thing shatters to the point of pieces parts flying all over.

I use to shoot TV picture tubes and other things that contained a vacuum with bow and arrow or rifle. It was always a let down. Nothing spectacular ever happened.

Things that had pressure in them conversely were spectacular.

 

[Deadalus]

Per means divide. Acceleration-miles per hour, 60 miles per one hour. If I travel at 60 mph for 2 hours, I multiply (60 miles/1 hour)×2 hours, the hours (the units) cancel out and we get 120 miles of distance traveled. That's how it works. You may be calculating the force but you are leaving out the per unit area it is affecting. You're implying it is the internal surface of the carboy, but so what? Two psi is miniscule for both skin and glass. There's around 4.4 psi at the bottom of a 10 foot deep pool.

 

[Deadalus]

There's roughly 2800 square inches of skin on a human. If said human dives down 10 feet, call it just 4 psi, that's 11,200 pounds of force on the skin. In your world, do people get crushed into pancakes in the deep end of the pool by that 5 and 1/2 tons of force?

 

[Bilsch]

There's roughly 2800 square inches of skin on a human. If said human dives down 10 feet, call it just 4 psi, that's 11,200 pounds of force on the skin. In your world, do people get crushed into pancakes in the deep end of the pool by that 5 and 1/2 tons of force?

People are incompressible, air on the other hand is.
Big difference.

P.S. Where is Vale71 when you need him?

 

[hotbeer]

People are incompressible, air on the other hand is.
Big difference.

P.S. Where is Vale71 when you need him?

People have air and other gasses in them. They are very compressible. The liquid and completely solid part of them is not compressible.

 

[Bilsch]

This thread reminds me of the 'CO2 blanket' discussions of the past.

 

[Deadalus]

People are incompressible, air on the other hand is.
Big difference.

P.S. Where is Vale71 when you need him?

You have no idea here what you are talking about.

Pressure
Clearly division.

Ignoring the beer in the carboy, assume it's empty, the pressure is the same throughout the inside. The force has to be applied to an area and square inches is what we use as a basis. If we say the pressure is 2 psi, that's the same as 288 pounds per square foot (by dimensional analysis). The object isn't suddenly going to break because we decided to change the basis and 288 is bigger than 2. It's the same exact pressure. The units are different. What you are doing wrong is you are just calculating force and not doing the division, which is the application of the force. Now if you keep increasing the pressure, you are increasing the force as the area is the same internally. But what you seem to think is a large pressure really isn't much at all.

 

[shoengine]

This is silly. The carboy cap will go before there is any internal failure. In fact I've had carboy caps fly off routinely during normal fermentation with a three piece airlock being the only check valve.

The exploding glass meme is getting old.

 

[day_trippr]

Indeed, I actually worm-clamp the carboy cap to not lose CO2.

There's a link at the bottom of the page to one of my carboy-racking posts. This was early on in my CO2-push racking - I'm using a bit more sophisticated gear now but not that different...

https://www.homebrewtalk.com/threads/fermentation-and-closed-transfers.671400/#post-8703000
Cheers!

 

[sibelman]

For reference..
1 psi in a 5 gallon carboy is exerting a force of 800 lbs on the internal surface.
2 psi would be 1600 pounds and so forth.
Just something to consider.

Explosion sounds scary of course. Maybe we've never heard of a pressure transfer explosion because death prevented the reports? Or maybe these scary numbers just mean we should be cautious with glass.

 

[Bilsch]

All of my statements are science fact and my numbers are correct. If you want to be cautious that is wise, if not then I wish you luck. But telling new people who don’t understand the physics behind this that it’s perfectly safe is reckless.

 

[BigDave1303]

I have a GF conical & closed loop transfer into kegs using gravity rather than bottled co2.
Firstly, During fermentation I have a blow off tube from the top of the FV to the out post of a keg & vent the gas post out into a bottle containing starsan mix as an airlock. This collects & purges the keg with co2 during fermentation.
Fermentation complete. I connect the keg out post to the bottom tap on the FV & connect the blow off tube to the keg gas post. This creates a closed loop.
Then gently open the FV tap, beer flows out under gravity filling the keg, displacing the co2 back into the top of the FV. No extra pressure needed.
I have the keg standing on scales tared to zero before transferring and stop at 18kg = 18 litres. I don't like to fill to 19 litres. Then I just bottle the last 2-3 litres.

 

[Qhrumphf]

I wouldn't ever apply pressure to a glass carboy. Not ever gonna be worth the risk.

Rather than applying pressure to the carboy, remove pressure from the keg, and connect the gas post of the keg to the where you were gonna apply pressure to your carboy. You've then got a balance line and can let gravity do the work. Beer flowing into the keg will push the keg headspace back into the carboy that'll in turn displace the volume of the beer flowing out.

It'll be slower, you'll have to devise a way to start a siphon, and you'll likely get more ingress than a system under pressure, however it's the only way I can come up with using glass to safely closed transfer.

 

[BigDave1303]

I wouldn't ever apply pressure to a glass carboy. Not ever gonna be worth the risk.

Rather than applying pressure to the carboy, remove pressure from the keg, and connect the gas post of the keg to the where you were gonna apply pressure to your carboy. You've then got a balance line and can let gravity do the work. Beer flowing into the keg will push the keg headspace back into the carboy that'll in turn displace the volume of the beer flowing out.

It'll be slower, you'll have to devise a way to start a siphon, and you'll likely get more ingress than a system under pressure, however it's the only way I can come up with using glass to safely closed transfer.

Agree, getting the syphon started would be the biggest problem in the OP's situation. Perhaps filling the beer line with boiled & cooled water. Connect the co2 return line first, then connect the water filled line to the top of the liquid out on the carboy. When that is snapped onto the keg post the water should start to pull a syphon. Not tried it but I think it should work depending on the head space in the carboy. It will dilute the brew but not by much.

 

[Qhrumphf]

As far as "the carboy cap will pop off before the carboy fails", it strikes me the same as using a PRV as a spunding valve or relying on a GFCI to bail you out of bad electrical practice. A failure safety mechanism is not an excuse to use unsafe practices.

 

[shoengine]

As far as "the carboy cap will pop off before the carboy fails", it strikes me the same as using a PRV as a spunding valve or relying on a GFCI to bail you out of bad electrical practice. A failure safety mechanism is not an excuse to use unsafe practices.

Have you ever used a carboy cap before?