15.5 gallon keg volume and liquid level questions

[BrewBeemer]

How many ounces does it take to fill a 15.5 gallon keg bottom to reach the straight sides or shall I say to a FB should one fit tight within the kegs straight sidewalls?
When a keg is filled with 15.5 gallons of liquid what is the liquid level measurement measuring from the 3 1/8" diameter pocket in the center of the keg to the surface?

 

[Donasay]

this depends on the keg, there are several different types of kegs manufactured with some variability to the shape and size of the dome on the bottom. You will just have to test with your keg, but I can't imagine it will be much.

 

[Schlenkerla]

FYI - Sabco 15.5 gal keggle.



inches - gallons
1.20 - .5
2.25 - 1
2.75 - 1.5
3.5 - 2
4.125 - 2.5
4.75 - 3
5.25 - 3.5
6 - 4
6.5 - 4.5
7.25 - 5
7.75 - 5.5
8.5 - 6
9.125 - 6.5
9.75 - 7
10.25 - 7.5
10.875 - 8
11.5 - 8.5
12.125 - 9
12.75 - 9.5
13.375 - 10
14 - 10.5
14.625 - 11

 

[Bobby_M]

My full false bottom takes .875 gallons or 3.75 quarts before I start seeing the water hit the perf sheet. On mine, 14 gallons is at the top seam where it starts tapering for the neck. You really need to calibrate your own though and make sure the keg is nice and level when you do it.

 

[BrewBeemer]

The kegs I have collected so far are;
3-15.5 Anheuser Bush
1-15.5 Jack Daniels Brewery
1-15.5 Lind Brewing
1-15.5 Thirstybear Brewing
2-7.75 Anheuser Bush
1-7.75 FullSail Ales
1-15.5 Firestone a different looking keg vs the others with those rectangle stampings. It MUST GO or exchanged for a Anheuser Bush keg unless I murder it into something else becoming useless, plasma cutting practice?

All of 'em have the same bottom and top radius and drop from the outside edge to the center hence the same volumes before the straight sides begin.

With a 10 gallon large grain bill like a stout with water added i'm at 18 gallons of volume, get my drift extending the kegs taller? Electric heating is another totally different idea also just in the thinking stages.

Schlenkerla; are those numbers Sabco has printed up on their net that I can find? BTY thanks for the posting those numbers, a starting point.

Bobby; when you have the liquid level at the FB was your FB sitting in the keg bottom where the sides just begin the taper radius narrowing down? This a flat screen FB, domed up, down, pie tin shaped domed up or down?
Reason asking all the above kegs are original without the tube, check ball or tops cut out, i'm shooting in the dark here as far as volumes they can handle before I cut and extend 'em taller and by how much is why i'm asking these questions.

 

[Bobby_M]

MY FB is completely flat, 15" diameter and sits right at the curve .. see here: https://www.homebrewtalk.com/showthread.php?t=69860

I honestly think the keg will handle just about any 10 gallon grain bill you throw at it. I just mashed 28 pounds and could easily see it handling another 2-3 pounds.

30lbs + 10 gallons of water is less than 14 gallons in the vessel. To be honest, if the keg was any taller you'd have a hard time stirring. If you need to go larger, you might want to start looking at a larger diameter vessel. You could also just augment those larger beers with 2lbs of DME.

 

[BrewBeemer]

Seems like a water fill for different sections of the keg bottom to straight sides, straight sides to just before the start of top taper (good area for weld extending), measuring the fill process with a flashlight, mechanics mirror and gallon containers will be needed. This all thru the neck on uncut kegs to figure how much taller I wish to go. I read on another forum's chart punching in numbers I would need a 18 gallon volume for a big bill. This is only 6.25" inches taller allowing 1.25" per/gal in height using 15.34" keg ID as a number, not that much taller to still hand stir. This would add 5 gallons without the keg filled to the 12" rim opening still allowing for a water layer above the grain bed. If i'm going to scratch build kegs why limit myself from the get go, danger thunker in action? Heck may need to add more or less than those above measurements, testings needed before I cut anything, i'll shut up now.
Enjoy the 4th everyone and be safe.

 

[Bobby_M]

I just think you're overcomplicating it when starting with a keg is supposed to make it easier and cheaper. If you want a 20 gallon MLT, I'd look elsewhere.

 

[dstar26t]

or just estimate the height like you've done already and multiply by 1.5

 

[billtzk]

I just think you're overcomplicating it when starting with a keg is supposed to make it easier and cheaper. If you want a 20 gallon MLT, I'd look elsewhere.

Agree. If I were building a 15 or 20 or 30 gallon brewery, I wouldn't be looking at using converted kegs. Kegs are for 10 gallon breweries.

 

[BrewBeemer]

Agree. If I were building a 15 or 20 or 30 gallon brewery, I wouldn't be looking at using converted kegs. Kegs are for 10 gallon breweries.

I want to be able to brew up to a 10 gallon big bill batch if I wanted without being limited by the mash and boil pot sizes i've read about. I'm not into 15 20 or 30 gallon brewing volumes as you replied billtzk, thanks for your reply anyway.
Looking back at Brewpastor's post 4-25-06 on his 13-F STOUT Russian Imperial Stout for 10 gallons of wort, total grain bill 50#, total water 17.94 gallons.
On another forums calculator chart I came up with 18.05 gallons for mash volume. Both beyond the limits of a standard 15.5 keg and this is for a 10 gallon brew session not 15, 20 or 30 gallons.
With my AB kegs filled to 15.5 gallons the level is 1 7/8" below the top of the kegs neck where the spear inserts. This same volume would be right at the overflow location of a keg thats been cut for a 12" lid, no extra space for sparge water above the grain. This would be a design limited system already. Cutting and a little extending would solve this problem. One must also allow for liquid space above the grain bed besides space for fly sparging inside the keg instead of sprinkling on the floor. Maybe i'm wrong at thinking ahead and building a system once right for my needs than wasting money rebuilding or hashing up a undersized system failing my needs, my wallet isn't that fat.
First off the collection of kegs I have are free so it's only about milling off the tops before the taper then adding a 6 1/2 inch taller body from another keg, the labor of milling apart and welding back together are free only costing me my retired time.
I would do this for both the mash and boil pots, volumes as needed when the details are figured out.
I do not want to spend money on larger thin gauge pots when I already have a collection of free thick walled kegs besides wanting to keep a small even diameter looking narrow single tier system.
Block party has started need to get my bier mug filled. Have a safe 4th full of suds.

 

[Bobby_M]

Devil's Advocate here... stirring a mash all the way up to the top of an unmodified keg is pretty hard to begin with. Trying to jam 40+ lbs of grain in that diameter is going to be a doozy. I hope you post pics though, it sounds like a cool project.

 

[BrewBeemer]

Bobby; I just pulled apart a tennis ball blowing machine, salvaged a high quality 90 VDC 6-60 rpm gearmotor with electronic speed control. No way would I want to hand stir even a standard keg of mash with my bad back I have. Lucky to stand upright and walk an hour a day. I'll just keep collecting items as they become available for a way down the road future build. MRI's and Ortho surgeons come first and a slow process at that. Go here test there, many MRI's this so far is only a 3 year battle. Been down with back injuries since late 2002. This allows me time to collect more items and different ideas. I now have a Hypertherm Max 20 plasma in great condition it works, had a Miller tech friend check it out and all was well. He used to do service on Hypertherm units. It was offered to me for $125 complete I had to grab it even though it's a little underpowered for my needs. I'll follow my ideas as these extra kegs are available and free that I can cut up.
From seeing other builds on this forum from basic to fully automated I don't have a problem with a basic keg length extension to solve a posssible future brewing volume problem.

 

[BrewBeemer]

Devil's Advocate here... stirring a mash all the way up to the top of an unmodified keg is pretty hard to begin with. Trying to jam 40+ lbs of grain in that diameter is going to be a doozy. I hope you post pics though, it sounds like a cool project.

I see no problem with what you call "Trying to jam 40+ lbs of grain in that diameter is going to be doozer".

As stated before extending the kegs a little plus a gearmotor to mix.

Looking at the chart on "How to Brew by John Palmer"
http://www.howtobrew.com/appendices/appendixD-2.html
Figure 168 grainbed depth comparison the taller grainbed helps vs
a shorter mash tun plus the amount and locations of the drains also helps. Unless Palmer is full of beans I like his chart results vs just opinions without charts. Bobby; I only have one shot at building a system not being able to alter as problems arise. Thin budget thick headed (German) ideas.