Keg to Kettle (MK I)


Find yourself in need of an upgrade?  Come across a hot deal for an old AB keg, or just have one laying around?  Here’s simple method to mod a keg to work as a perfectly simple brew kettle.

This upgrade will take you away from the stovetop brewery, so be sure to consider a propane burner and all the accessories.  Moving to a kettle this size will get rid of any boil over problems, especially in 5 gallon batches, and remove the need to boil extra water to top up your volume.

Tools used (my source):
5″ Angle Grinder with center handle position (Harbor Freight)
5″ x 1/4″ Metal Grinding Disk (Home Depot)
5″ 80 grit Flap Disk (Home Depot)
1-1/4″ Schedule 40 Unthreaded Female to Threaded Male PVC adapter (Home Depot)

I also needed a drill and drill bit to modify the pipe coupling, but if you lack those, you should be able to talk the fine folks at your local home improvement store to blast a hole in it after purchase.

The best place to start is in the beginning, so after you’ve acquired your keg (keep that part on the up-and-up, don’t just snag one sitting outside a bar,) you’ll need to pull the dip tube or spear out of it.  Mine had been missing for a while, possibly since I acquired it, so I didn’t have that to video.  There’s all kinds of videos out on there on the subject, but here’s a good one that should help you out:

When you head to your home center, bring along the measurement of your keg’s dip tube bore, on the inside, and double check your pipe fitting’s diameter.  The fit needs to be lose enough to easily spin while inserted, but not so lose the cut wanders.

I mention in the video to use a grinding disk instead of a cutting disk.  The process of cutting in a circle put forces on the disks in awkward directions, so a thin one has a high probability of grenading during the cut.  The 1/4″ thick disk will have enough stay-together power to bust the job out while being able to make a tight turn without removing too much metal.

Clockwise from top: 5" Flap Disk (80 grit), 5" Metal Cutting Disk, 5" x 1/4" Metal Grinding Disk
Clockwise from top: 5″ Flap Disk (80 grit), 5″ Metal Cutting Disk, 5″ x 1/4″ Metal Grinding Disk

Once you’ve got your parts and tools together, drill a hole on the center line of the PVC fitting and wind a bit of wire through the holes and around the angle grinder’s handle.  Before you tighten the wire down, use the intended lid, or just a large one from the kitchen, to mark a circle on the top of the keg.  Install your grinder’s handle in the center or upward facing threaded hole, then check the fitting’s position.  Insert the fitting into the dip-tube bore and adjust the handle until the grinder disk is inside of the marked circle.  That’s were you want to be!  Tighten it down and you’re ready to rock.

Fitting attached to handle.
Fitting attached to handle.

Be serious about the PPE (Personal Protective Equipment) on this one.  Safety glasses, face shield, gloves and hearing protection are a very good idea.  The keg is a nice, big, hollow resonator and grinding on it is loud as hell.  Other standard hot flying metal precautions apply.

Grinder with handle and center fitting
Grinder with handle and center fitting

Socket the PVC fitting into the dip tube bore, point the tail end of the grinder at the sky then hop to it.
This process doesn’t need much force applied, the weight of the grinder will work for you.  The operator is just the trigger holder in this case.  It is a good idea to take breaks every few minutes.  Your angle grinder might be as cheap as mine and get really hot during the cut.  I was sure I’d let the smoke out on my first good keg mod, but it keeps trucking.

You’ll know you’ve finished the cut when the center of the keg falls into the lovely mix of old beer, dirt and metal dust that has accumulated in the bottom.

All that is left is to swap out for the 5″ 80 grit flap disk and give the cut area a good sanding.  Remove any sharp edges and burrs around the rim, check the fit of your lid and if all is well, you’re done!

There are a few ways to do this mod, but this is a great method for any and everyone who wants to get their hands dirty.  It needs a small amount of tools and about 15 minutes of your time.

Go out there and make a kettle.  Then have a beer, you’ve earned it.



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