Filling kegs by weight??

[Morrey]

New 14G uni tank to arrive soon so I'm doing my pre-planning before my first 11G brew in this tank. Since I'll be filling two corny kegs with a closed transfer system, I wont be able to visually watch how full the kegs are.

I figured my best bet is to find a suitable scale, zero out the keg tare weight and fill figuring 5 gallons of beer at 8.4 lb per gallon which is a shade over the weight of water.

If there is a more simple or effective way of measuring with the lid closed, please tell me the options.

Other than a standard bathroom scale, is there a commercial scale that can be suggested for this application? Thanks!

 

[Queequeg]

This is how I do it. Parcel scales are the type of thing you want. Got mine off eBay.

You can also tap the side of the keg. That is less accurate though.

 

[lump42]

You could give the Ball and Keg a try. Simple concept that should work.
https://www.ballandkeg.com/

 

[Derp]

If you cold crashed the fermenter you should be able to see a condensation line as the cornies fill.

 

[Morrey]

This is how I do it. Parcel scales are the type of thing you want. Got mine off eBay.

You can also tap the side of the keg. That is less accurate though.

Set of postal scales on Amazon is $32. Less than I thought and weighs objects starting at 6 ounces up to 440 pounds.

You could give the Ball and Keg a try. Simple concept that should work.
https://www.ballandkeg.com/

This is a cool gadget. Something like this would be fun to make as a DIY to monitor the level in the keg w/o picking keg up.

 

[Weezy]

Another option is to daisy chain the kegs together. Uni tank to keg1 via out post, then in post of keg1 to out post of keg2. Leave poppet of keg2 open. Fill both in one go. Keg1 will fill to bottom of in post. Keg2 will get everything else.

 

[raysmithtx]

That's close to what I do. I usually want 4 gallons in my corny keg. I multiply the water weight (8.33 * the O.G). So if I had an OG of 1.055 I would multiply 8.33 *1.055 * 4. I tare my scale with the empty corny on it and then open the valve stopping at my determined weight (35.16 pounds in this example).

I was surprised that the weight difference can be so significant. Using 8.33 * 4 gallons is 33.32 pounds. And taking the OG into consideration is 35.16 pounds). Nearly 2 pounds difference or about 2 pints.

Been doing this for quite a while and never had a problem.

 

[Horseflesh]

If the ball & keg cost half as much, I'd have a half dozen. At the current price, I have zero.

 

[Qhrumphf]

Works like a champ for filling sankey kegs.

Probably a way to adapt it to a cornie keg. Or rig something similar.

https://www.gwkent.com/proline-ii-keg-filler-fob.html

Or you just do it the old school way and attach a gas QD and let it overflow.

 

[jwelch1103]

I use a scale, 42 Lbs into each 5 gallon keg. Works well.

 

[hopularkid]

Just fill one keg and weigh it compared to the empty keg. You only have to do it once, then you'll know the weight.

 

[oceanic_brew]

If the ball & keg cost half as much, I'd have a half dozen. At the current price, I have zero.

Yup

 

[Qhrumphf]

The weight math is actually very easy. Determine empty keg weight. To that, add 8.34*volume*SG. 8.34 is an approximation and a more accurate result could be had factoring in the temp, but it's close enough. That's volume in gallons and weight in pounds. Even easier in metric- SG*liters=weight in kg.

In most cases, 5 gallons of beer will be 42-42.5 lbs (plus keg weight).

 

[bleme]

I've never done it myself, but I've seen many kegerators with flow meters installed. I assume they would work backwards as well...

https://kegbot.org/

 

[day_trippr]

[...]I assume they would work backwards as well...

Maybe, maybe not.

I run a half dozen SF800 meters on my keezer and SwissFlow is specific about flow direction.
I doubt they'd hold their rated accuracy running in reverse, even assuming they'd output a proper pulse.

In any case, I fill by weight as well. It's easy enough to do with the right scale and I like having an accurate initial volume to plug into my RaspberryPints tap list.
I had a keg kick this weekend with just one ounce indicated remaining.
I like that...

Cheers!

 

[Queequeg]

You could give the Ball and Keg a try. Simple concept that should work.
https://www.ballandkeg.com/

That's a nice an simple solution but unfortunately for me I live outside the US so postage makes it an expensive solution

 

[Pkrd]

I use a luggage scale...
http://www.dx.com/p/byxas-1-7-lcd-h...le-black-50kg-10g-2-x-aaa-248433#.Wbell62B1P0

If you split your siphon line and fill both kegs at once through the out posts they should end up the same level.

 

[betarhoalphadelta]

That's close to what I do. I usually want 4 gallons in my corny keg. I multiply the water weight (8.33 * the O.G). So if I had an OG of 1.055 I would multiply 8.33 *1.055 * 4. I tare my scale with the empty corny on it and then open the valve stopping at my determined weight (35.16 pounds in this example).

I was surprised that the weight difference can be so significant. Using 8.33 * 4 gallons is 33.32 pounds. And taking the OG into consideration is 35.16 pounds). Nearly 2 pounds difference or about 2 pints.

Been doing this for quite a while and never had a problem.

Wouldn't you want to use FG? During fermentation, yeast converts sugar (which contributes to OG) into CO2 which gets pushed out the airlock and alcohol which is lighter than water. CO2 may seem like it doesn't count for weight, but that's what is lost to create the difference between OG and FG.

But either way, you're measuring a specific gravity of a liquid which is a measure of density, and thus if you want your final number to come out right you should use the liquid's density as it is on the day of kegging rather than pre-fermentation density.

 

[ajdelange]

I used to use scales but found that with Sankeys it is much easier to just put your hand on the side of the keg near the top and wait until you feel cold. When you do move your hand to the dome part. Picture your thumb next to the coupler and your little finger next to the rim. When you sense cold in your little and fourth fingers shut off the beer.

With relatively new Sankey's you can see the level of the beer by the condensation line. With a really beat up old keg you might not be able to.

I never did it this way with Cornles. I'm sure the hand on the side part would work but not sure there is room on the top but there might be room for a couple of fingers. This method is very simple (with Sankeys) and gives a very precise fill.

 

[Qhrumphf]

Wouldn't you want to use FG? During fermentation, yeast converts sugar (which contributes to OG) into CO2 which gets pushed out the airlock and alcohol which is lighter than water. CO2 may seem like it doesn't count for weight, but that's what is lost to create the difference between OG and FG.

But either way, you're measuring a specific gravity of a liquid which is a measure of density, and thus if you want your final number to come out right you should use the liquid's density as it is on the day of kegging rather than pre-fermentation density.

Exactly. The CO2 released is mass lost. Beer weighs less than its wort. It's one calculation that's actually easier with SG than Brix/Balling/Plato.

Now, if it's already carbed, then there's added mass from CO2 returned. But it's miniscule compared to what's blown off in fermentation.

 

[TAK]

Another option is to daisy chain the kegs together. Uni tank to keg1 via out post, then in post of keg1 to out post of keg2. Leave poppet of keg2 open. Fill both in one go. Keg1 will fill to bottom of in post. Keg2 will get everything else.

This is what I do. Although, instead of opening the PRV on Keg2, I hook up one more line off the liquid out post of Keg2 and drop the end into a mug of starsan. This way, on the occasion that I have more than 2 kegs worth, I can collect the extra.

 

[raysmithtx]

Wouldn't you want to use FG? During fermentation, yeast converts sugar (which contributes to OG) into CO2 which gets pushed out the airlock and alcohol which is lighter than water. CO2 may seem like it doesn't count for weight, but that's what is lost to create the difference between OG and FG.

But either way, you're measuring a specific gravity of a liquid which is a measure of density, and thus if you want your final number to come out right you should use the liquid's density as it is on the day of kegging rather than pre-fermentation density.

Since I'm using closed loop fermentation I am more concerned with the volume at the time of kegging and not the volume after the end of the fermentation. I need to know the volume into the fermentor by weight because I can't see through the corny keg.

 

[Weezy]

Since I'm using closed loop fermentation I am more concerned with the volume at the time of kegging and not the volume after the end of the fermentation. I need to know the volume into the fermentor by weight because I can't see through the corny keg.

But you won't be able to distinguish between trub and beer, going by weight.

 

[raysmithtx]

But you won't be able to distinguish between trub and beer, going by weight.

Since trub takes up space and contributes to volume I really don't care. I just don't want to clog the gas tube in the corny by overfilling.

 

[Weezy]

I'm confused.

 

[bleme]

I'm confused.

It sounds like he is pumping all his trub into the kegs also, so not only can he not see through his corny, he can't see through his transfer tube either. I've never considered doing something like that but evidently it works for him.

Not all the weight lost between OG and FG is trub though. A lot of it is CO2.

 

[ajdelange]

I relying on memory here but 2.065 grams of extract yields 1.000 grams of ethanol, 0.11 grams of biomass and 0.955 grams of CO2. You can look it up in DeClerck if someone wants to check me on that.