How full (Weight) do you fill your Kegs?

[AlexKay]

FIFY... Carbonation occurs only at the interface of liquid and gas ie: The greater the surface area, the faster it goes, and the reverse is also true.

I say "theoretically" because I haven't done a side-by-side comparison.

Gas/surface interface area is important, yes, but it's not going to be a simple (linear) relationship, because diffusion of CO2 away from the interface matters, too: without diffusion, the tiny volume right at the interface comes into Henry's-Law equilibrium and then you're done carbonating. I suspect (i.e., I haven't done any math) that diffusion is the limiting step that makes set-and-forget force carbonation so slow. And then add in agitation (compressor motor vibration if you're in cold storage) and convection. It gets complicated.

So yes, I wouldn't be surprised if a keg filled to the tippy-top needed much longer to force carbonate. But I also wouldn't be surprised, given the above, if the amount of extra time wasn't all that much. I haven't done the measurement.

And I'm still confused about why anyone would leave good beer in the fermenter. If people are really worried about carbonation time, give the keg a shake once a day. I suspect (again, no measurement, so just a guess) that a completely filled-to-the-top keg that's shaken every now and then will carbonate faster than a partially-filled one that's left alone.

And now I'm thinking ... how about a little shaker motor you could clip on to a keg that you're carbonating?

Or punt on the issue completely, and get one of those corny lids with a built-in carbonation stone.

 

[mac_1103]

And I'm still confused about why anyone would leave good beer in the fermenter.

ISTM that there isn't much difference between leaving good beer in the fermenter and blowing good beer out the gas post of the keg you're filling. Ideally one would find someplace else to put any excess good beer. Some such places have already been mentioned.

 

[Broken Crow]

I say "theoretically" because I haven't done a side-by-side comparison.

Gas/surface interface area is important, yes, but it's not going to be a simple (linear) relationship, because diffusion of CO2 away from the interface matters, too: without diffusion, the tiny volume right at the interface comes into Henry's-Law equilibrium and then you're done carbonating. I suspect (i.e., I haven't done any math) that diffusion is the limiting step that makes set-and-forget force carbonation so slow. And then add in agitation (compressor motor vibration if you're in cold storage) and convection. It gets complicated.

So yes, I wouldn't be surprised if a keg filled to the tippy-top needed much longer to force carbonate. But I also wouldn't be surprised, given the above, if the amount of extra time wasn't all that much. I haven't done the measurement.

And I'm still confused about why anyone would leave good beer in the fermenter. If people are really worried about carbonation time, give the keg a shake once a day. I suspect (again, no measurement, so just a guess) that a completely filled-to-the-top keg that's shaken every now and then will carbonate faster than a partially-filled one that's left alone.

And now I'm thinking ... how about a little shaker motor you could clip on to a keg that you're carbonating?

Or punt on the issue completely, and get one of those corny lids with a built-in carbonation stone.

I had an 'inner panic' at mention of beer coming out the PRV, sorry about that... I routinely let star san shoot out mine in sanitizing but don't want to think about cleaning beer out of it.
Since I'd drain my fermenter from the top down, the last beer in it would ususally go into large 750ml or 1.5l fliptop bottles with dextrose, but then I bought my cheap 1.6G baby kegs for the last and occasionally cloudy beer...I'd never toss it! I would just drink it first myself and never present it to company!
As to that 'shaker-motor' idea; There was a product some years ago called the "Beer Buddha".. it was a little Buddha statue powered by a wall-wart with some kind of pendulum inside..you hung it on the side of your keg and it would be continually 'tapped' causing ripples on the surface of the beer to increase surface area exposure. I've never tried tried it, but I did use a carb-stone cap until I realized it only made about 6 hours difference.
Again though: Spunding and transferring already carbed beer is ideal...wish I had a ferm-chamber

 

[Deadalus]

I had an 'inner panic' at mention of beer coming out the PRV, sorry about that... I routinely let star san shoot out mine in sanitizing but don't want to think about cleaning beer out of it.
Since I'd drain my fermenter from the top down, the last beer in it would ususally go into large 750ml or 1.5l fliptop bottles with dextrose, but then I bought my cheap 1.6G baby kegs for the last and occasionally cloudy beer...I'd never toss it! I would just drink it first myself and never present it to company!
As to that 'shaker-motor' idea; There was a product some years ago called the "Beer Buddha".. it was a little Buddha statue powered by a wall-wart with some kind of pendulum inside..you hung it on the side of your keg and it would be continually 'tapped' causing ripples on the surface of the beer to increase surface area exposure. I've never tried tried it, but I did use a carb-stone cap until I realized it only made about 6 hours difference.
Again though: Spunding and transferring already carbed beer is ideal...wish I had a ferm-chamber

There was another one too that would shake the whole keg but I don't remember the name.

Beer clears with time. Much of my brewing has been done in carboys. I know how much beer is in there and the amount of sediment. If it's more than the keg will hold, I can just draw off a growler or baby keg even. Let's just say it would be a Stanley or flip top growler. If you wanted to, you could go with those stainless steel growlers that pressurize or the pet ones for closed transfers. Two 3 gallon kegs work well for amounts between 5-6 gallons but then you still need to be somewhat careful. I just drew off a 1.75 keg to bring camping and I just gently rocked the keg and listened for splashing, then switched to the five gallon keg when it was almost full.

One might leave a little beer in the fermenter not wanting to deal with carbonating that separately or dealing with sanitizing bottles or worrying about a closed transfer.

 

[tracer bullet]

I'm confused. I transfer absolutely as much clear beer as I can.

I tend to have 5, 5.25, maybe sometimes 5.5 gallons in my fermenter so it's not a thing I'm ever concerned with. Subtracting the yeast cake on the bottom of course means I can't recall the last time I've been concerned with overfilling a keg. I'm pretty good at my calculations and end up at this amount about every time.

Do folks go over the amount this intentionally or accidentally?

 

[mac_1103]

Do folks go over the amount this intentionally or accidentally?

I overestimated losses on the Imperial IPA I just kegged (the dry hops didn't absorb as much liquid as I thought they would). So I've got half a gallon in a PET soda bottle with a carb tee (aka - ghetto minikeg). Guess I'll drink that first.

 

[Closet Fermenter]

Yeah I don’t understand the whole filling kegs by weight thing.

Ok, so here’s as good a reason as any. I sometimes like to do 10 gallon batches. I use a keezer for dispensing, but I don’t want to lift 10 gallon kegs over the side. So, I will split a 10 gallon batch between two kegs. Monitoring weight is a good way to tell when the first keg is full and I need to transfer the hoses to the second keg.

You could say that I do may weighing “old school”. I take a regular bathroom scale, and step up on it while holding the empty keg, add 42# to that as my target. As the keg starts to get full, I just step up on the keg and heft the keg to see how close I am to the target.

 

[bwible]

Ok, so here’s as good a reason as any. I sometimes like to do 10 gallon batches. I use a keezer for dispensing, but I don’t want to lift 10 gallon kegs over the side. So, I will split a 10 gallon batch between two kegs. Monitoring weight is a good way to tell when the first keg is full and I need to transfer the hoses to the second keg.

You could say that I do may weighing “old school”. I take a regular bathroom scale, and step up on it while holding the empty keg, add 42# to that as my target. As the keg starts to get full, I just step up on the keg and heft the keg to see how close I am to the target.

That makes sense. I forgot about the guys doing 10 and 20 gallon batches with cylindroconicals, glycol, and lab grade stuff. I’m doing 3 gallons at a time with my little Foundry 6.5 and a couple glass carboys. I have to brew twice to fill a 5 gallon keg and I still don’t go through everything I brew quickly.

 

[Deadalus]

Ok, so here’s as good a reason as any. I sometimes like to do 10 gallon batches. I use a keezer for dispensing, but I don’t want to lift 10 gallon kegs over the side. So, I will split a 10 gallon batch between two kegs. Monitoring weight is a good way to tell when the first keg is full and I need to transfer the hoses to the second keg.

You could say that I do may weighing “old school”. I take a regular bathroom scale, and step up on it while holding the empty keg, add 42# to that as my target. As the keg starts to get full, I just step up on the keg and heft the keg to see how close I am to the target.

That would be quite a hoist! Due to the design of my kegerator I couldn't even fit my 10 gallon in through the top.

Nothing wrong with the way you are doing it but I was wondering if you could run a jumper to the second keg and chain them together? Like chaining and purging kegs with starsan. The first keg would fill up almost completely and then you could just stop when the fermenter is empty. This is dependent on the volume in the fermenter again. If it is under 10 gallons, just push a little out of the first keg once the fermenter is empty. If you are over, you still have to decide whether to keep or dump the extra, and it would of course risk overflow of the 2nd keg. I'm not sure that it would save any time or anything but maybe slightly smoother process.

 

[Bullhog]

I fill till I get 42.2 lbs or till it starts shooting out the spunding valve.

 

[Closet Fermenter]

That makes sense. I forgot about the guys doing 10 and 20 gallon batches with cylindroconicals, glycol, and lab grade stuff.

Nothing that fancy; just using a half-barrel keg as a fermenter. I like doing the 10 gallon batches because it really doesn’t take much more effort, and there’s only one cleanup and twice the beer!
Also, I like to prime the kegs with sugar and carbonate naturally. Brewing more volume gets me ahead so the beer has more time to carbonate and condition before I need it. If I do get a little behind, I can force carb one keg, and prime the other with sugar. The second one will easily be ready by the time I finish the first.
Hoping to get a small kegerator and just slide the whole thing in and skip the transfer altogether. Could serve using a floating dip tube.

 

[day_trippr]

Yeah I don’t understand the whole filling kegs by weight thing.

Here's my motivation:

Cheers!

 

[whoaru99]

Do folks go over the amount this intentionally or accidentally?

Accidentally maybe. But, seems like on forums comments come across in certain ways, figure of speech, etc., that can convey a lot more negative connotation than perhaps actually intended. Or, I hope so anyway.

 

[terrypratt1]

thanks for all the replies (and like almost anything brewing related there are many methods used). I do prefer not to spund (and lose all that aroma - at least IMO) - so I have Gas line back to fermenter and use gravity transfer vs. feeding CO2. Appreciate all the input - each reply has its own value! I always aim for a bit more than keg capacity as so much effort goes into the process I prefer a full keg vs. some waste (Okay - I do transfer to a few growlers what is left after weight target and get to sample before full carbonation).

I asked mostly because of course without taking the lid off I cant be sure how close to a full 5 gallons I really am - and not doing that after all the effort to be oxygen free! Never measured 5 gallons of water and then checked by scale and calculations - but that suggestion is pretty simple and effective (and on my To Do list now).

Thanks again to ALL - much appreciated.

Terry

 

[Closet Fermenter]

thanks for all the replies (and like almost anything brewing related there are many methods used). I do prefer not to spund (and lose all that aroma - at least IMO) - so I have Gas line back to fermenter and use gravity transfer vs. feeding CO2. Appreciate all the input - each reply has its own value! I always aim for a bit more than keg capacity as so much effort goes into the process I prefer a full keg vs. some waste (Okay - I do transfer to a few growlers what is left after weight target and get to sample before full carbonation).

I do the closed loop gravity transfers as well. Since Ive been doing this, I’ve really noticed how the roasted barley flavor is preserved in my stouts.

To your question about any “leftovers”; I have a small 1.6 gallon torpedo keg that I use to put any extra in, unless it’s just a couple bottles or so. Then, I just purge it a little with my tank and force carb it. It gives me a little taste of what’s coming, even if it’s a little under conditioned. If it is too small amount to put in the tiny keg, I either bottle & prime it, or just swirl it up into the yeast for harvesting; just depends on how much is left.
Although that salvage beer will not be as good, it’s always better than store bought!

 

[elproducto]

Some complicated processes here. I just tare the scale with the keg and stop at about 18.5kg.

 

[day_trippr]

Many digital scales will time out and shut off before they're filled, and the tared keg weight goes away forever. That is why I calculate the target gross weight instead: if the scale shuts off I can lift the keg off, turn the scale back on, and once it's zeroed itself put the keg back on and keep going...

Cheers!

 

[Closet Fermenter]

Hey! I was looking for something entirely unrelated, and happened across this!

Bluetooth Propane Tank Scale

 

[day_trippr]

Reviews are not exactly exemplar https://play.google.com/store/apps/details?id=com.flameking.propanemonitor

Biggest complaint is battery life and that the cylinder has to be removed to access the power switch.
This is a representative example...

"Worthless. Don't waste your time or money. Successfully connected to my phone once. The two AA batteries go dead in a few days if the scale is left on. It is apparently meant to be powered on only when propane is being consumed requiring you to remove the scale from under the bottle and switch it off then switch it on and insert it under the bottle again the next time you are using gas. "

 

[Bramling Cross]

With this thread in mind, I was very careful about getting an accurate weight on a 5gal keg of bitter that I packaged today. The TG on the beer was 1.007 and the full up weight in my Slimline Torpedo keg was 51lbs on the dot including the floating dip tube, .25oz of keg hops, ascorbic acid, and 10ml of keg finings.

 

[Deadalus]

Haha so now that I am fermenting in unis I had no idea how much beer was in there other than a vague idea as I didn't write it down! And I did need to get real close to 5 gallons in each of 2 kegs (for an event). I brewed 11 or so gallons. But I was reading along so I weighed my kegs on the bathroom scale and went with 42 pounds for the beer. Seemed pretty close watching the condensation on the side and final rocking. It's the answer to the universe anyway!

And now I'm freaked out a little 'cause when I finished that thought and looked up I saw this:

 

[catalanotte]

I transfer into a closed keg, so I don't know how much is in the keg. I use SSBrewTech Buckets so I'll stop just before the beer gets down to the bottom of the racking arm or until beer comes out of the hose I have attached to gas post. If the latter I'll drain about 3/4 of a pint out so the beer level is below the bottom of the gas post.

Same process here. Ever have issues with gunk in the gas post? I noticed a number of gas leaks at the co2 post bung since I started doing this. I try hard to not get an overflow, but it happens. I’m about to take the offending posts apart and see what they look like.

 

[JohnDBrewer]

For most beers, I stop at 41.5 to 42.0 lbs. Any beer still left in the fermenter (if it's a 5gal batch) goes into a 2 ltr soda bottle, forced carbed and immediately sampled.

 

[Spartan1979]

Same process here. Ever have issues with gunk in the gas post? I noticed a number of gas leaks at the co2 post bung since I started doing this. I try hard to not get an overflow, but it happens. I’m about to take the offending posts apart and see what they look like.

Not that I've noticed.

 

[balrog]

GallonVolume V=(454/3785)*(LBWT/SG)

SG like 1.010
LBWT = Beer Weight = Total Weight of keg+beer on scale minus *known* keg weight = (TW - KW)

Yes, you have to measure empty keg before starting to fill. It's a data point. Don't tell me you don't measure that and write it down for all posterity. You know you do.

Solve for TW and fill on the always on when plugged in postal scale.

Having said all that, I fill till it overflows the gas in side.
(and yes, for a couple of my kegs, I always find out too late that I have a couple of kegs I *REALLY* mean to trim the damned gas in dip tubes back a bit)

 

[CascadesBrewer]

I saw this video come out a few days ago. It would old work with kegging cold beer (I tend to only mess with cold crashing dry hopped ales, and the occasional lager that I brew), but basically involves sticking a temperature changing sheet to the fermenter. As the keg fills with cold beer, the sheet changes color. In the video, the color change is very distinct. The video has a link for a product on Amazon UK, but a search for "Cold Sensitive Color Changing Vinyl" should turn up products. I see a 1ft x 5ft roll listed on Amazon for $9 US.

 

[beren]

What the sankey mfgs say is if you don’t measure the exact amount going into the keg, you can tilt it on a 30° and fill until beer comes out the gas port. Can do the same with a soda keg if you cut the gas dip tube. If not just fill it until it comes out the gas port. This way there is some headspace still. If you do the tilt, make sure the gas port is at the mid point of the tilt, not the highest or lowest spot.

 

[ba-brewer]

If you do the tilt, make sure the gas port is at the mid point of the tilt, not the highest or lowest spot.

Why the mid point?

I tilt my kegs with a couple pieces of a paint stirrer stick and have the gas post at the lowest point when filling. I don't know the angle but guess it is less than 30 degrees.

 

[beren]

Why the mid point?

I tilt my kegs with a couple pieces of a paint stirrer stick and have the gas post at the lowest point when filling. I don't know the angle but guess it is less than 30 degrees.

Well, if the gas coupler is at the top, then you’ll have almost no headspace, and if it’s at the bottom, you will have the most headspace. I guess if you have it at the low point, you could use a lesser angle.

I know it’s different than a Sankey keg, but with those the gas port is also in the middle

 

[ClaudiusB]

I calculated all our tank target gross weight and recorded it on its RFID tag. As a backup, the cross weight is recorded on the back of the tank number.
On fill day I scan the tag if the weight is not readable on the number tag. and watch the scale.