Stainless vs brass for CO2 system?

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patwestlake
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Stainless vs brass for CO2 system?

Post by patwestlake » Wed Aug 14, 2019 6:28 pm

What's the difference in getting a stainless reg vs a brass one (from China)? With the rest of the brewing gear I'm OK with what's best where, but I'm new to kegging and am working back from the keg. Post keg will be stainless as it's on contact with the beer. I know I need pressure control rather than flow but not sure about where the money goes in a reg. 2 gauges a must, obviously!

Cheers, Pat
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LeeH
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Re: Stainless vs brass for CO2 system?

Post by LeeH » Wed Aug 14, 2019 6:39 pm

When dealing 500 psi, I’d rather buy one from a know source.


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mozza
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Re: Stainless vs brass for CO2 system?

Post by mozza » Fri Aug 16, 2019 10:44 am

I’ve tried the cheap welding ones and in my opinion they’re a waste of time. Mine gave up after about a year. I now use one of these [https://www.themaltmiller.co.uk/product ... regulator/] and has been going strong for a couple of years now.
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PeeBee
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Re: Stainless vs brass for CO2 system?

Post by PeeBee » Fri Aug 16, 2019 3:57 pm

patwestlake wrote:
Wed Aug 14, 2019 6:28 pm
… 2 gauges a must, obviously!
Pardon? Put that out of your head for starters! Just one gauge is needed to tell you how many PSI you set the regulator's low-pressure side. Many regulators have two gauges, but for CO2 the second gauge (high pressure side) tells you only if the cylinder is empty, or not empty - pretty uninformative! This second gauge is more useful for compressed gases (like "mixed gas" in beer circles). CO2 in cylinders (or capsules) is not a compressed gas, it's liquid.

The following diminutive regulator has a fixed output (I use "secondary regulators") but you can see I've added my own low pressure gauge, but it doesn't really need it (I set the low pressure output on the secondaries). The manufacturers can't help but attach a high-pressure gauge to the regulator but here it's tiny and pretty useless except for showing "I'm empty" or "I'm not empty", which is all an enormous gauge would tell you.
20180317_091052_WEB[2].jpg
20180317_091052_WEB[2].jpg (55.62 KiB) Viewed 359 times
(EDIT: Piccie sort of answers the original question - There's brass and stainless steel (and aluminium, and the cylinder is steel) attached to that regulator. Unlike beer, CO2 is pretty inert - not entirely, but it is for our purposes - so won't be transferring anything to worry about into your beer).

(EDIT2: Oops, this cylinder is aluminium not steel - notice that still gets the contents an "E" number for food use).

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Kev888
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Re: Stainless vs brass for CO2 system?

Post by Kev888 » Sun Aug 18, 2019 10:17 am

Over the years I've had regulators made of brass, aluminium, stainless or a combo; all are fine if used in reasonable conditions. The design and quality of manufacture are far more important.

Chinese equipment (either bought direct, or from a fly-by-night UK re-seller) has the potential to be substandard rubbish, not made to any safety or quality standards - even if claimed and printed on the product. So unless you have some way to verify the quality then it would be a gamble, and it is up to you whether you choose to take that or not.

Personally, for something potentially dangerous like a primary regulator, I'd want it to be of a known and decent brand and/or from an established and reputable retailer who backs the quality and source. I would also want it to have decent pressure release valves, of a pressure lower than the burst pressure of any part of my system (which regulators designed for other purposes my not have). Though if you have PRVs elsewhere, such as on kegs or couplers, that might be less important.
Kev

patwestlake
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Re: Stainless vs brass for CO2 system?

Post by patwestlake » Mon Aug 19, 2019 9:24 pm

Cheers all

Point taken on the "Known/unknown" supplier bit.

PeeBee - I guess I was just transferring my years of sport diving into my brewing world - checking gauges for contents was just part and parcel of not dying, so becomes a bit OCD. Point taken though!

Pat
FV : Weiss Weiss Baby! Weissbier
Conditioning (bottles) : Citra SmaSh, Kolsch, Dirty Harry (Ghost Ship), Galaxy Delight

Next : Patersbier, some sort of Goes, Cindy Juice

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Re: Stainless vs brass for CO2 system?

Post by Jocky » Wed Aug 21, 2019 12:51 pm

PeeBee wrote:
Fri Aug 16, 2019 3:57 pm
patwestlake wrote:
Wed Aug 14, 2019 6:28 pm
… 2 gauges a must, obviously!
Pardon? Put that out of your head for starters! Just one gauge is needed to tell you how many PSI you set the regulator's low-pressure side. Many regulators have two gauges, but for CO2 the second gauge (high pressure side) tells you only if the cylinder is empty, or not empty - pretty uninformative! This second gauge is more useful for compressed gases (like "mixed gas" in beer circles). CO2 in cylinders (or capsules) is not a compressed gas, it's liquid.
Have recently switched to using CO2, but I have to question this.

Is there not a stage in between 'not empty' and 'empty' where the liquid is exhausted, but you still have several litres of CO2 in a compressed state? At this point the gauge will drop as the pressure is released in dispensing your beer. This means that the second gauge acts as an 'imminently empty' warning - when it starts to drop you still have a small reserve (a few litres maybe? How to calculate this) before you drop below serving pressure.

The one thing I do know is that the second regulator is useful for checking for leaks in the system using this method:
- Pressurise serving system (or at least the bits you want to test)
- Turn off CO2 at bottle
- Wait 5-10 minutes. If the 2nd gauge drops then you have a leak. The first gauge will eventually drop, but the second gauge will drop sooner.
- Test parts of the system in isolation to figure out what part is leaking.

For me this second use makes the additional cost of a 2 gauge regulator worth it.
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PeeBee
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Re: Stainless vs brass for CO2 system?

Post by PeeBee » Wed Aug 21, 2019 3:30 pm

Jocky wrote:
Wed Aug 21, 2019 12:51 pm
… Is there not a stage in between 'not empty' and 'empty' where the liquid is exhausted, but you still have several litres of CO2 in a compressed state? …
There surely is! But it does depend on what is being served. I'm mainly hand pumped beer and can get a few days warning - although I was fetching gas on Christmas Eve not so long ago and that could have been a bit of a disaster (convinced me I needed two cylinders, not one).

If you are serving keg beers for a bit of a session the warning (if you even notice it) may not be long enough to see the night out.



I too use the high-pressure gauge as a "leak-test". But only because it's there, not because I think the second (high pressure) gauge is an essential item.

(For the sake of other readers: When the liquid CO2 runs out the cylinder will have remaining gaseous CO2 at about 860psi, whereas a fresh "mixed gas" cylinder will have 2-3,000psi and will most likely be bigger. So work it out for yourself, but I'd recommend rigging up an alarm to go off at less than 750-800psi to get at least some useful warning 'cos you may not notice otherwise).

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Re: Stainless vs brass for CO2 system?

Post by LeeH » Fri Aug 23, 2019 4:31 pm

In a nutshell, by the time you notice the primary gauge dropping, your bottle is near dead.


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PeeBee
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Re: Stainless vs brass for CO2 system?

Post by PeeBee » Sat Aug 24, 2019 11:50 am

LeeH wrote:
Fri Aug 23, 2019 4:31 pm
In a nutshell, by the time you notice the primary gauge dropping, your bottle is near dead.
That's the one!

Okay, so I'm a wanna-be squirrel and my dream "nutshell" is rather big. So I'm not too good at "in a nutshell". Or, "in a nutshell", I waffle a lot.

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