Author Topic: When is the keg full?  (Read 923 times)

Offline MNWayne

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When is the keg full?
« on: April 30, 2019, 01:31:39 PM »
I'm at the point where I'd like to move into closed transfer to kegs. I don't have a sight glass on my fermenter, so no way to tell how much is going into the keg. I don't want to fill until beer exits the gas port, and taking off the lid to check the level defeats the purpose of closed transfer. The only ideas I have come up with is filling the kegs by weight, or making a sight glass. How do others do it?
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Offline kramerog

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Re: When is the keg full?
« Reply #1 on: April 30, 2019, 01:53:26 PM »
I normally have less than 5 gallons in the fermenter so overfill is generally not a problem.  I know some people do it by weight.

Offline RC

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Re: When is the keg full?
« Reply #2 on: April 30, 2019, 02:31:16 PM »
The easiest thing to do is go by weight, as Kramerog suggests. Filling with 42 lbs of beer would yield 5 gal for most final gravities. If you want it very exact, or if you have a very atypical final gravity, then use the Beersmith tool called Weight to Volume. Enter the SG of the beer and then adjust the weight in the "Current Container Weight" field until the estimated volume reads 5 gal.

Offline Robert

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Re: When is the keg full?
« Reply #3 on: April 30, 2019, 02:53:34 PM »
May I ask why you don't want to fill until beer exits the gas port? 
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Offline MNWayne

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Re: When is the keg full?
« Reply #4 on: April 30, 2019, 10:32:02 PM »
More cleaning due to beer in the gas side. More wasted beer since I'd have to draw a few pints/quarts.
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Offline Robert

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Re: When is the keg full?
« Reply #5 on: April 30, 2019, 10:46:41 PM »
Fair enough.  FWIW I've never found any extra cleaning to be involved, as I disassemble and clean all the keg parts between uses anyway, and it's not much extra to clean another QD and some tubing at racking time.   But if it's loss you're trying to avoid, and it's not an option to just plan on a little extra brew length to account for it, I guess you need an accurate way of judging an invisible fill level, and weight would be the obvious choice.   I don't use  Beersmith, but that tool RC mentioned sounds like a real help.
« Last Edit: April 30, 2019, 10:48:24 PM by Robert »
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Offline HopDen

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Re: When is the keg full?
« Reply #6 on: April 30, 2019, 10:58:32 PM »
Just fill until it exits the blow-off. The waste is minimal and you should clean everything after the keg is empty anyways. Why waste the money on a scale just to weigh your beer? As a precaution after filling this way, I always hose off the kegs then spray down with Starsan. Pop a little CO2 in there too. This is what I do and I've never had any issues.

Offline BrewBama

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When is the keg full?
« Reply #7 on: May 01, 2019, 02:33:18 AM »
The Q is how do others do it.  I fill thru the out post until it comes out the in post. Then attach CO2 and pull beer until I no longer hear gurgling. That way I know the keg is full and the headspace is filled with CO2.

If you discard the beer after pulling it out of the keg to create head space or leave that same beer in the fermenter; the amount, wether considered wasted or not, would be the same.

If you don’t want to do that get you one of these gizmos: https://www.kegerators.com/equipment/ball-keg-monitor/

As far as extra cleaning: it simply gets drained into the blowoff jar then dipped into the 5 gallons of sanitizer I just purged from the keg prior to closed transfer right alongside the tube I used to fill the keg.

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« Last Edit: May 01, 2019, 02:49:30 AM by BrewBama »
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Offline Robert

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Re: When is the keg full?
« Reply #8 on: May 01, 2019, 02:35:02 AM »
If you discard the beer after pulling it out of the keg to create head space or leave that same beer in the fermenter; the amount, wether considered wasted or not, would be the same.


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Brilliant observation.   The only reason not to fill until beer exits the gas port and then draw off to  create a precisely known amount of headspace is, if you absolutely know that your fermenter capacity is insufficient to fill to the gas port.  Then to know exactly how much beer vs. headspace you have absolutely requires a precisely measured fill, only practically achieved by weight, unless you can meter the flow.  So the choices you are left with are:  1) buy a fancy scale to weigh the beer filled into your keg down to the fraction of an ounce above tare weight, having first calculated the weight of a given volume based on gravity (which is not as straightforward as you might at first think.)  2) pay even more for some kind of flow metering system.  Or 3) fill to overflowing and draw off, "wasting" some beer.  Note you will "waste" the exact same amount of beer in scenarios (1) and (2) but it will be far more complicated and expensive to do so.  Losses are part of brewing.  All brewers expect losses at every stage of the process.   They plan ahead and account for them.  Returning to top:  make sure your fermenter volume is sufficient, problem solved.
Rob Stein
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Offline BrewBama

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When is the keg full?
« Reply #9 on: May 01, 2019, 02:44:07 AM »
Exactly. I don’t consider the beer drawn off to create headspace waste any more than I consider wort loss to grain absorption, trub, hydrometer samples, etc. waste. It’s all pre-planned loss.


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« Last Edit: May 01, 2019, 02:51:01 AM by BrewBama »
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Offline MNWayne

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Re: When is the keg full?
« Reply #10 on: May 01, 2019, 03:12:11 AM »
All very good points. Was leaning toward weight, but now filling until beer exits the gas port makes more sense. Many thanks.
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Offline tommymorris

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Re: When is the keg full?
« Reply #11 on: May 01, 2019, 06:35:49 AM »
I fill until some beer comes out of the gas port. Then I clean that mess with a towel and some diluted bleach. That is definitely waste: a few ounces of beer on the ground. Then I connect the keg to co2 and draw off a few ounces into a glass. I drink that beer so it cannot be called waste.

Offline Joe T

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Re: When is the keg full?
« Reply #12 on: May 01, 2019, 09:36:12 AM »
When I do closed transfers I go by weight. I bought a $30 scale just to do this but I find it comes in handy for weighing all sorts of things, like my grist, transfers to the travel keg, exactly how much is left in that serving keg, and even other things outside of the brewery. Nothing wrong with filling until it comes out the gas port except that it requires being more attentive when it's almost full. With the scale I can do other chores in the brewery while just keeping an eye on the weight, always knowing exactly where it's at. Not necessary but definitely nice to have.

Offline Robert

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Re: When is the keg full?
« Reply #13 on: May 01, 2019, 11:42:22 AM »


Then I connect the keg to co2 and draw off a few ounces into a glass. I drink that beer so it cannot be called waste.

Warm, flat and yeasty, but not wasted!

If you're doing a gravity transfer with the gas line returning to the fermenter,  flow will stop when the level in the line equalizes,  and you'll only leave a small amount in the line.

I transfer pushing with CO2.  I used to place the line out of the gas post in a bucket of iodophor, and it would give an audible signal -- rapid bubbling  -- that beer was flowing.  When the bubbling slows radically,  stop those other chores in the brewery instantly, the keg's nearly filled.  Thanks to forum member macbrews for the idea.

My current adaptation is to put a picnic tap on the gas post.  Bleed pressure periodically as needed to keep flow going -- sort of a poor man's counter pressure fill.  Then when beer finally exits the port, you needn't spill a drop.  Then a picnic tap over on the liquid side to draw off another pint, and no "waste" if you drink it, or at least cook with it.  But like BrewBama, I consider it part of my planned losses.  It's minimal though.
Rob Stein
Akron, Ohio

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Offline ynotbrusum

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Re: When is the keg full?
« Reply #14 on: May 01, 2019, 12:46:41 PM »
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