how to know when the keg is almost full?

[danders1999]

I do gravity, closed transfers from fermentor to corny keg, thru the keg's beer-out post, attaching the keg's gas-in post to the fermentor's airlock. I never know exactly how much actual beer is in my fermentor (it's not visible), therefore have trouble ascertaining when the target keg is (almost) full. I've thought about getting the Duotight Flow Stopper, which has a floating ball that stops the flow when liquid (beer) reaches (and comes out) of the gas post...i.e. keg is full. My concern is at that point, isn't it already too late? -- i.e by the time the float stops the flow beer will have already filled the keg too high for adequate CO2 insertion? (my CO2 dip tubes have been shortened to increase usable keg capacity). I guess I could try weighing the target keg before filling and monitor the weight during filling, but wonder if weight varies by beer style/FG. Happy to entertain any good approaches for this!

 

[Donoroto]

I do gravity, closed transfers from fermentor to corny keg, thru the keg's beer-out post, attaching the keg's gas-in post to the fermentor's airlock. I never know exactly how much actual beer is in my fermentor (it's not visible), therefore have trouble ascertaining when the target keg is (almost) full. I've thought about getting the Duotight Flow Stopper, which has a floating ball that stops the flow when liquid (beer) reaches (and comes out) of the gas post...i.e. keg is full. My concern is at that point, isn't it already too late? -- i.e by the time the float stops the flow beer will have already filled the keg too high for adequate CO2 insertion? (my CO2 dip tubes have been shortened to increase usable keg capacity). I guess I could try weighing the target keg before filling and monitor the weight during filling, but wonder if weight varies by beer style/FG. Happy to entertain any good approaches for this!

Two methods:

First, easiest, is put an open gas connector on the gas post. When foam and beer start spurting out, it is full. The short gas tube leaves sufficient head space in the keg. (The extra 8 ounces you can get by cutting the IN tube short is not worth it. Get new ones.)

It is very difficult to overfill a fully assembled keg.

Second: cold-crash the beer in the fermenter. At transfer you can see the condensation on the outside of the keg, and feel the liquid level (it is cold!) as it rises.

Good luck!

 

[Donoroto]

And, CO2 does not care how much or little head space there is, it will dissolve into the beer either way.

 

[Minbari]

Open the prv. When beer comes out, it's full

 

[Craigerrr]

I connect a gas connector on the gas post with a length of beer line. Usually there is enough foam on transfer (I either ferment under pressure, or spund, so I am fully carbed at transfer) that a wee bit of foam will come up in the line letting me know I am full.
Don is correct on the headspace/co2 thing. It is surface area, not head space volume that affects co2 being absorbed. Doesn't really matter how full you keg is, the beer surface area is the same.

 

[GFHomebrew]

You could tare your bathroom scales and fill this way 19kg should = 19lt.

Filling to the brims a great way to mitigate O2 ingress .

Yup when beer starts comming out the PRV she's full.

@Minbari. What about them Plato things you got they would make it more easy no?

 

[TWS]

If filling keg after cold crashing, I find the humidity in these parts (I live in Georgia), will cloud the exterior of the keg as the liquid rises.

 

[Minbari]

You could tare your bathroom scales and fill this way 19kg should = 19lt.

Filling to the brims a great way to mitigate O2 ingress .

Yup when beer starts comming out the PRV she's full.

@Minbari. What about them Plato things you got they would make it more easy no?

you might. when its empty you have to account for the empty weight of the keg and hoses. they arent perfect, but would prolly get within 1/4 gal

 

[Donoroto]

If filling keg after cold crashing, I find the humidity in these parts (I live in Georgia), will cloud the exterior of the keg as the liquid rises.

I'm a bit north of Atlanta and, except for the last couple days, it's usually humid enough for that.

 

[danders1999]

Thx all for your replies. I did notice keg exterior condensation when filling after the 1 time I cold crashed prior to kegging...(I've put cold-crashing on hold until I get a suck-back prevention means in place). I hear you all on the 'fill it 'til it comes out the gas post' approaches, and my current approach seems to be a flavor of that. Main thing I was wondering is if my shortened gas tubes are a problem, since I'm thinking they may eliminate close to all keg headspace. To quantify 'shortened', they've been cut basically flush with the bottom of the gas post (i.e. are about .5" long). I did see the replies about limited headspace not being an issue, though wondered about 'no' headspace.

@Trialben I may also explore weighing as an approach using my grain scale to see if I find that reliable, as it would be cleaner that having to clean excess beer out of my gas-out tube. And @Minbari good point about accounting for the hoses when weighing; I'm thinking I'd also need to account for beer weighing a bit more than water (+1% in the case of FG 1.010). It's always something!

 

[Minbari]

Thx all for your replies. I did notice keg exterior condensation when filling after the 1 time I cold crashed prior to kegging...(I've put cold-crashing on hold until I get a suck-back prevention means in place). I hear you all on the 'fill it 'til it comes out the gas post' approaches, and my current approach seems to be a flavor of that. Main thing I was wondering is if my shortened gas tubes are a problem, since I'm thinking they may eliminate close to all keg headspace. To quantify 'shortened', they've been cut basically flush with the bottom of the gas post (i.e. are about .5" long). I did see the replies about limited headspace not being an issue, though wondered about 'no' headspace.

@Trialben I may also explore weighing as an approach using my grain scale to see if I find that reliable, as it would be cleaner that having to clean excess beer out of my gas-out tube. And @Minbari good point about accounting for the hoses when weighing; I'm thinking I'd also need to account for beer weighing a bit more than water (+1% in the case of FG 1.010). It's always something!

just not convinced this would be a reliable way to do it.

if you did the "gas out" idea, simply put a piece of hose on the gas fitting into container. no mess and easy to tell its full.

 

[Over The Cliff Brewing]

I do gravity, closed transfers from fermentor to corny keg, thru the keg's beer-out post, attaching the keg's gas-in post to the fermentor's airlock. I never know exactly how much actual beer is in my fermentor (it's not visible), therefore have trouble ascertaining when the target keg is (almost) full. I've thought about getting the Duotight Flow Stopper, which has a floating ball that stops the flow when liquid (beer) reaches (and comes out) of the gas post...i.e. keg is full. My concern is at that point, isn't it already too late? -- i.e by the time the float stops the flow beer will have already filled the keg too high for adequate CO2 insertion? (my CO2 dip tubes have been shortened to increase usable keg capacity). I guess I could try weighing the target keg before filling and monitor the weight during filling, but wonder if weight varies by beer style/FG. Happy to entertain any good approaches for this!

Don't waste your money on that ball float thingy. I bought one and I'll say it didn't work. I ended up using the fittings for spares on my spunding valves.