60/40 Beer Gas Test



I’m a newcomer to dispensing via a kegerator at home.

Before pressurising a keg, I have run a test on my mixed gas regulator to verify proper use.

As a test I connected my gas line to my regulator (pushes in to gas tight JG 3/8 fitting) and set the PSI to 35 after opening the valve on my mixed gas cylinder.

After around a minute I completed the test and noticed the regulator had frosted as had the gas line (only slightly).

I’m curious if this happened because I wasn’t pressurising the keg or if theres likely a leak somewhere?

It’s a new regulator so I’ll check all the seals etc but wondered what else I could inspect or if this was just a result of temperature and having no keg connected.

For context, I conducted the test in my garden and the temperature was around 15 degrees.





  1. Thanks Bill, I did suspect a leak but being a newbie wanted some opinions.
    I’ll nip everything I can up and post my findings.
    Where are the most common areas of failure?
    Again, bearing in mind it’s a new regulator.
    I may need to inspect the cylinder itself as that is very old.


  2. Make sure the rubber o ring is on the thread that connects to the gas bottle, if it’s missing take the grey collar of an unused 3/8 fitting and remove the rubber washer from there that will fit onto the end of the threaded part. Also fill a spray bottle with soapy water and spray all joints on your primary, secondaries, couplers, gas pump(if fitted) also check to make sure your not loosing gas through the vent of the gas pump, easiest way to check is to put a pipe into the vent fitting and the other end into a bucket of water and with the gas supply turned on to the pump the only time you should have bubbles in the bucket is if the pump clicks, if you have a continuous flow of bubbles when the pump isn’t ticking you have a leak through your vent and the pump needs replacing.

    Check on your primary valve around the brass blow offs and around the fitting for your 3/8 gas pipe for bubbles as sometimes can be not very noticeable.

    Make sure seals are not split and in good condition on your coupler.

    Hope this helps you out, keep us posted if you sorted it

  3. Thank you too Connor for the detailed reply.
    I’ll keep you posted, there is no pump in play here and I only have a primary regulator.
    I’ll check out all of your applicable guidance.


  4. Hi Connor & Bill,
    Many thanks for your guidance.
    The problem was at the collar – I nipped up the collar connecting to my cylinder by another half turn using my wrench and this eliminated my earlier frosting issue.
    In terms of beer and gas line length, what would you suggest?
    I know that I need to factor in room temperature, type of gas, and CO2 volume of my keg, into calculating my PSI output but how does length of lines contribute to the calculation?


  5. Gas line doesn’t mater as long as it’s long enough to reach your gas reg and coupler, as for product length it’s difficult to say as I’ve only worked with remote coolers and having a recirc pump to keep the line chilled to the tap helps but obviously in your case you won’t have that so i probably would say shorter the better as less to pick up heat to the tap also if will help to be insulated
    Is your tap screwed onto the fridge or have you got a proper beer fount clamped to a bar top and drilled a hole through the fridge for the product line?
    What product you pouring?
    What Is the keg storage temperature?
    I will find the co2% and equilibrium pressure for 60/40 for you

Do you have a better answer? Leave a reply or an opinion