If you’ve been
thinking of making the step up to 10-gallon batches, and you just bought a Keggle Brewing Keggle Kit. You
need a 15.5-gallon Sankey-style keg, (unless you know how to weld or have a local welding shop that will do the work)and some basic power tools. The end product
is commonly referred to as a “keggle,
As with most DIY projects, protective eyewear is absolutely required.
And given that there are flying, red-hot metal particles involved in
this project, I highly recommend safety goggles instead of just glasses.
In addition, hearing protection is also recommended. Cutting and
grinding metal is very loud and can cause hearing damage. A cheap pair
of earplugs will protect your hearing and make the project a lot more
comfortable to complete.
First step: vent the keg
you bought your keg reconditioned, you must bleed off the interior
pressure. Even empty kegs aren’t really empty, in most cases. There will
be a small amount of stale beer and a decent amount of pressure still
inside. YOU MUST RELIEVE THE PRESSURE ON THE KEG BEFORE ANY CUTTING OR
DRILLING. Failing to follow this guideline could result in serious
My preferred method for safely depressurizing a keg is to drill a small hole near the outside edge of where you are going to cut to top. It is
advisable to cover the top of the keg with an old towel to prevent a
geyser of funky, stale beer from reigning down on you or shooting up in
Marking and cutting the top
Use a permanent type marker (a Sharpie, for example) to mark the
guideline for the cut. One easy way to do this is to tie one end of a
string around the marker and the other end around the center valve on
the keg. This low-tech method yields a very nice circle that is pretty
close to perfect. If you’ve got a really steady hand, you can also just
lean the marker against the inside edge of the outer rim and run it
around the circumference of the keg.
common diameter for the opening on a keggle is about 12 inches I grind edge smoother to remove any burrs
For doing the actual cutting, you have a few options. The most
elegant choice is a plasma cutter. If you know someone who owns one of
these, this is the best way to cut a super smooth opening with minimal
fuss. If this isn’t an option (which is the case for most of us), you
can also use an angle or die grinder or various types of rotary tools.
Just to compare results, I used a RotoZip rotary tool for about half of
the cut and a Dremel rotary tool for the other half. For both tools, I
used their respective heavy duty metal cutting/grinding wheels (part #
RZMET2 for the RotoZip and part # EZ456 for the Dremel). I also tried
using my air grinder, but my compressor isn’t nearly powerful enough to
keep the grinder going long enough to make the cutting worthwhile. But
if you have a compressor you could do it this way as well.
The smaller the diameter of the cutting/grinding wheel, the smoother a
cut you can make. The tradeoff is that smaller wheels also take longer
to do the cutting. In my tests the Dremel (with a 1.5-inch wheel) took
about three to four times as long to cut the same distance as the
RotoZip (with a 3.5-inch wheel), but the resulting edge was smoother and
required less grinding and filing to make it safe for human contact.
Either tool did an adequate job, however. Expect to use two or three of
the RotoZip wheels and six or more of the Dremel wheels to complete the
cut. Buy double what you think you’ll need, just in case.
can also use an angle or die grinder to cut out the keg top. This
project is an excellent excuse to purchase more power tools. Experiment
with different methods to find the best result.
Once you’ve got the top out (Figure 2), you should smooth out the
rough edges around the opening. Take extra care during this step, as the
steel will be very sharp. I used an angle grinder as a first step to
wear down the edge (Figure 3). I followed this up with a finer grinding
stone attachment on my Dremel and some manual sanding with very coarse
sand paper on a sanding block. My resulting edge in these photos, while
not the prettiest in the world, is smooth to the touch and safe for
general brewing use. The opening doesn’t need to prove Pi to 20 decimal
points in order to have a working brew kettle, but it does need to be
safe for handling.
Adding the ball valve
Now we’re going to add a weldless bulkhead and ball valve to round
out the keggle. If you plan to go with a welded connection, you can skip
this section and consult with the welder. Most homebrewing gear uses
1⁄2-inch threaded fittings, so just make sure you standardize on that
Several homebrew suppliers offer weldless kits that include the
bulkhead and the ball valve. I opted to use Norther Brewer’s
bulkhead-only kit (catalog #7551) and a Blichmann 3-piece stainless
steel ball valve (available from many suppliers). I chose this
combination because all of the parts that touch the wort/beer are
stainless steel, and the Blichmann valve can be broken down for
cleaning. You can use any bulkhead setup or ball valve you like.
a 1⁄2-inch bulkhead, you’ll generally need a 7⁄8-inch hole. However,
you should always follow the manufacturer’s instructions, so if their
guidelines give a size other than 7⁄8 of an inch, go with what is stated
in the instructions.
Mark the spot for drilling a couple inches up from the bottom seam of
the keg. The inside bottom of a keg is sloped, so the closer to the
bottom you drill, the more of an angle your valve will sit at when
attached. Each type and shape of keg varies as to the degree of slope,
so make sure you don’t drill the hole too low. In my experience, it’s
better to go a little too high than too low, because you can make up for
a high valve with a dip tube.
Drilling the keg
Drilling stainless steel can be frustrating sometimes, to say the
least. The approach I take is to use a center punch to mark the initial
hole, then use a 1⁄8-inch twist bit to make a pilot hole, and then widen
the hole up to the proper diameter with a step bit (Figure 4). You can
get inexpensive step bits from Harbor Freight and most big-box auto
parts stores such as AutoZone.
keys to drilling stainless steel are: use lubricant (3-in-1 oil works
fine), drill at slow to medium speed, and use a lot of pressure.
Lubricant is very important when drilling stainless steel, as it is
critical not to get the metal too hot. If it gets too hot, the steel
will harden and become virtually impossible to work with. Use the oil
liberally, and reapply as necessary during the drilling process. You’ll
know it’s time to apply more when you see the oil evaporate in a small
puff of white smoke. At that point, stop drilling and apply more oil.
Instead of a step bit, you can use a hole saw. Some brewers have used
hole saws with excellent results, but my experiences have been hit or
the manufacturer’s instructions for installing the bulkhead fitting,
(Figure 5) and then attach the ball valve (Figure 6). At this point, you
could either add a hose barb fitting to the ball valve or connect more
complex plumbing, depending on your brewery setup.
Clean that keggle!
Once you’ve done all the cutting, grinding, drilling, and filing, the
inside of the keg is going to be nasty. Rinse it thoroughly with water
to remove all of the drilling lubricant and metal filings. Follow up
with an overnight soak in warm water and Powdered Brewery Wash (PBW).
Rinse thoroughly, and you’re ready to brew.