New Keg Design?

[CheeseJam]

Hi! This is my first post here, so I apologize if this this is the wrong section.

My friends and I love buying large quantities of beer in kegs to save money. We do not have a CO2 pump or anything, so we have to drink the beer quick or it goes bad. Personally, I think buying CO2 gas/pumps is a pain, and this got me thinking: Is there another keg design out there?

I have attempted to research the basics of why kegs pressurized with CO2 do not go bad. As I understand it, unlike oxygen, CO2 does not react badly with the beer and simply pressurized the keg. But, what if there was another way to pressurize the beer without CO2 or any other direct air contact?

If this has not been done before, I was thinking of designing a keg that does this very thing. Basically, some sort of bladder, or some other sturdier mechanism, inside a keg would contain the beer. Then, just regular old air could be pumped into the keg outside of the bladder, pressurizing the beer. The bladder would simply serve as a barrier from the air to the beer, while still allowing it to be pressurized. I think this would be a lot more convenient and a money saver. It could be applicable to homebrewers, beer lovers (like myself!), restaurants, bars, etc. Would the beer stay fresh using this method?

Does something like this already exist? If not, what are the drawbacks to a system like this? I'm not exactly a beer expert so any help would be greatly appreciated, thanks!

 

[Pratzie]

interesting idea, curious what kind of input u receive here.

 

[ong]

Check out the "party pig" -- it's a small keg that can be stored in the fridge, and uses a baking soda and vinegar charge to inflate a plastic bladder inside the keg.

 

[DanH]

But then you wouldn't have carbonated beer?

 

[CheeseJam]

Check out the "party pig" -- it's a small keg that can be stored in the fridge, and uses a baking soda and vinegar charge to inflate a plastic bladder inside the keg.

Thanks for the heads up on that! That is an interesting concept, but in the end, it seems to just have another fuel source (like CO2 tanks). I guess the idea I was thinking of involves no separate pressurizing source you need to buy, other than manual or electric air pumping. Is there a reason CO2 specifically has to be pumped into beer? Or does it just happen to be the cheapest gas that doesn't react with beer?

 

[CheeseJam]

But then you wouldn't have carbonated beer?

Does beer go flat fast just sitting in an untapped keg? I was thinking my concept would have a similar effect to an untapped keg that basically keeps shrinking in volume while remaining "untapped", but I don't know for sure.

 

[DanH]

I get it now. It probably wouldn't go flat without any head space I guess.

 

[Kosch]

It doesn't go flat in an untapped keg because the keg is pressurized and equalizes the CO2. It seems like your idea of using air to pressurize the chamber around the bladder would work, but it's going to have to be a fair amount of pressure (i.e. more than the pressure of the CO2 within the bladder). Could be a fun experiment, I think the toughest part would be getting a good seal all the way from inside the bladder to outside the chamber.

 

[amandabab]

Does beer go flat fast just sitting in an untapped keg? I was thinking my concept would have a similar effect to an untapped keg that basically keeps shrinking in volume while remaining "untapped", but I don't know for sure.

sort of reinventing the variable volume wine tank. beer needs a gas co2/co2-nitro mix

the worst idea ever was the hand air pump for kegs. making mediocre beer even worse at parties everywhere for decades.

beer with no co2 put under physical pressure is still a flat liquid under pressure.

 

[LBussy]

If you need to develop the amount of pressure needed to reach equilibrium anyway, I think you will eventually find it easier to not pump and use regulated pressure. Otherwise you end up with some of the same issues you currently have with party tappers, namely "that one guys" who thinks his beer cup equals fifteen pumps on the tapper. It would also allow the beer to go flat if you did not maintain equilibrium - let's say 15psi at all times if that is the proper carbonation/dispense level for your beer. Because now it's not about adding just enough pressure to dispense but it's maintaining correct pressures to keep the beer properly carbonated. In other words your proposed solution does not solve all of the issues inherent in the design of a party tap, while adding a pretty complicated bladder setup (compared to a simple tank.

All that to say it's not an idea without merit, but it might be an idea without a commercially viable advantage.

 

[mrwizard0]

I think it's an interesting idea. The first thing the pops into my head when I think of this is some sort of accumulator. You could hand pump air into the keg and the air would stay on one side and a piston would push down onto the beer

 

[trboyden]

The CO2 serves a couple of purposes, hence it's use. As others have pointed out, the CO2 helps carbonates the beer and replenishes naturally lost carbonation. It also forms a barrier to keep oxygen out. Lastly it serves as a pressurizing force to force the beer out of the keg.

Ignoring the first two purposes of CO2, providing a force to drive beer out of a keg could be done in a number of ways. A variation on the bladder method could be water added to the keg that pushes on the bladder and forces the beer out. The water could serve a dual purpose of keeping the beer cold.

The problem with a bladder system in general is that the art of beer handling is to minimize complexity. Adding the components for a bladder system means more parts that require cleaning and sanitation and that could fail.

Another design possibility is a syringe or caulking gun type design, where a piston and o-ring pushes the contents out of the main container. The possibility of failure still remains (seal failure), but in theory, the piston should be a lot easier to clean and sanitize than a bladder type system. It would also allow for a variable size container with one physical container.

 

[rhoop]

Home RO water storage containers have a bladder system to pressurize and dispense water after being run through the RO system. However, you'd need to have a top that could screw off so you could clean it. I think that would be difficult to make without access to manufacturing systems.

If your serious about this, and could design something in CAD, there are places in China that will fabricate prototypes relatively inexpensively...

 

[JRems]

The keg you are describing already exists. It's a bag in ball design. It's calked a key keg. http://www.keykeg.com/en/ultimate-design/

 

[trboyden]

The keg you are describing already exists. It's a bag in ball design. It's calked a key keg. http://www.keykeg.com/en/ultimate-design/

Ah, the Internet. Of course it has...