Tired of transporting kettles full of scalding wort? Tired of siphoning from kettle to carboy? The answer to these problems is simple: put a spigot in your brew kettle.

Though neither simple nor trivial, this is a worthwhile project for any homebrewer. If you have the tools and the expertise, you can do the work yourself. If not, it won’t cost much to hand the job over to a professional.

The primary question is how to attach the spigot: by silver soldering, silver brazing or professional welding. A fourth option is to buy a Fermentap weldless kit. It can add a spigot to any kettle, whether it’s aluminum, stainless steel or an enameled cooking pot (see “No Weld, No Worries” on page 50).

First, some decisions

Regardless of which option you choose, the first decision is where to put the hole. If you’re using a converted Sankey keg as your kettle, the hole must be high on the sidewall, above the “chime.” (The chime is the place where the bottom, side and support ring meet.) If it’s a flat-bottom kettle, you’ll want the hole closer to the bottom, so you can drain liquid, rather than siphon.

If you’re doing this yourself, assess your tools, your skills and your kettle. If you have a thin-walled kettle, it won’t be too difficult to drill the hole. If you have a converted keg or a stainless-steel kettle, it won’t be so easy. Stainless steel is tough stuff; cheap drill bits won’t cut it ... literally. You’ll need something more professional, like good high-speed steel bits, titanium-tipped bits or one of those “sixteen sizes in one” Uni Bore multi-drills.

At my local Builders Square, a titanium bit costs $20 and a Uni Bore is $31. That’s quite a price for cutting one hole! If you want the tools anyway, go ahead. Or maybe your homebrew club could buy the equipment for a drilling session. (A tip from the pros: Use heavy pressure at 500 rpm or slower, plenty of the right lube, and a Uni Bore.)

The alternative is having a professional welder pierce your kettle. Welders have the right bits and lots of special cutting tools. And it shouldn’t be expensive: A good welder should be able to do the entire job, from hole-cutting to welding, for less than $50 labor.

Either way, first you have to figure out which fitting to stick through the hole. One choice is a nipple, the other is a coupling. If you’ve never worked with pipe, a nipple is pipe with two male threads, one at either end. A coupling is a larger-diameter pipe with female threads inside each end.

Like anything in homebrewing, there are contradictory opinions on the best fitting to stick through your pot. I’d suggest a coupling because it allows you more freedom to make changes to your set-up.

Think about it. If you have a coupling installed into the pot, you'll want a 3”-5” nipple between the pot and the ball-valve spigot. If you install a nipple, the ball valve would screw right on. But simpler isn’t always better.

Let’s say you install a short nipple and your ball-valve spigot is close to the pot. The “prop wash” from your burner might heat it enough to burn your hand. To extend the ball valve you’d have to screw on a coupling, another nipple, then your ball valve. If you had installed a coupling, you could simply unscrew your nipple and substitute a longer one.

Either way, these fittings are not expensive. Couplings and nipples cost $4 or less; a half-inch ball valve and spigot should be under $30. Ball valves come in brass or stainless; the conventional wisdom is that stainless is much better.

 Now it’s time to attach the fitting to the kettle. Three popular methods are silver soldering, brazing with oxy-acetylene, or finding a sanitary welder who’s familiar with the brewing or dairy industry. Here’s a rundown on the trio of options, with a note of caution for do-it-yourself types: We can’t teach you metal working in a couple of pages; that’s a job for community education.

Silver soldering

Silver soldering is the simplest answer. Silver soldering is just like any other soldering job, whether it’s plumbing, automotive body work or electronics. It  just requires a different solder, different flux and more heat. (Flux cleans and protects surfaces while soldering and helps solder to flow properly once melted.)

If you own a MAPP gas torch it might get you by. Otherwise you’ll need an acetylene-air or oxy-acetylene torch for sufficient heat output.

We asked Harris Welco, a national supplier of welding products and machinery, to suggest the best products for silver soldering stainless steel to stainless steel. They recommend two products, StayBright silver solder (430° F melting point) and StayBright 8 silver solder (535° F). Both are rated by the National Sanitation Foundation for food service use. Harris also says you’ll need Stay-Clean liquid flux.

If you're planning on silver soldering, keep in mind a few basics. Silver solder works best when the two surfaces overlap at least three times the thickness of the thinnest metal. If you’re going through the wall of a keg with a full coupling, there would be only the “overlap” of the pot’s wall. But if you were adding a half-coupling to a thin-walled kettle, there would be plenty of “overlap” where the bottom of the coupling meets the pot’s wall.

If you decide to silver solder a coupling or nipple into your pot, start by drilling a very tight hole, one with only .002-.005 (two to five thousandths of an inch) clearance. Harris Welco technician Jeff Heuerman says, “When the silver solder is drawn into the gap, filling it, that’s where you get your strength.” Silver solder should not bead up, like a weld filet. Actually, you could think of silver solder as an extremely hot, hot-melt glue.

Silver solder is expensive, over $30 a pound. But you can buy just a few ounces. The Stay-Clean liquid flux retails for $6.40. The bottom line: Silver solder is simple and effective, but it may crack after a year or two of homebrewing service. While you can do it yourself, it’s just not as rugged or long-lasting as silver brazing or welding.

Silver brazing

Silver brazing produces a connection that’s comparable to professional welding, and it’s not as expensive as it sounds.

What’s the difference between brazing and welding? Glad you asked. Welding occurs at temperatures high enough to melt the parent metals, both your pot and the fitting. Brazing requires far lower temperatures and uses a filler metal that melts at temperatures lower than the metals being joined.

Silver brazing means brazing with a filler (rod) that contains pure silver. You also need an oxy-acetylene welding torch set. Silver brazing rod and the proper flux should cost less than $20 and you’d be able to braze several pots.

What pots? Stainless steel, of course. Not enamel or (shudder) aluminum. Aluminum can be “brazed” but that’s a different and very tricky subject. Stainless, on the other hand, brazes very nicely.

Harris Welco recommends a rod called SafetySilv 56. It contains 56 percent pure silver plus some copper and nickel, perfect for any stainless steel pot or kettle. When brazing stainless steel you need Stay-Silv Black Flux. “Regular white flux is for lower-temperature brazing applications,” says Jeff Heuerman. “Stainless steel takes more heat to braze than copper or steel and the flux has a tendency to burn up because its active range is lower. So I recommend Black Flux; it has a greater heat range.” The rod, SafetySilv 56, is a low-temperature brazing alloy (its melting point is 1205° F), making it easy to work with even for occasional welders.

The bottom line: If you have an oxy-acetylene welder, or know someone who does, silver brazing is a good choice. It nearly equals professional welding for durability. And you’ll love this silver brazing rod; it welds easily and the puddle is very controllable.

Hire a welder

The final choice is to find a “sanitary welder,” a welder who works with stainless or other exotic materials, not industrial steels. For this project I hired Troy Terwilliger of Twig’s Welding in Lansing, Michigan. He travels throughout the state, installing and repairing breweries and microbreweries. Using a $4,000 TIG system (tungsten inert gas), he installed a coupling and a half-coupling in my thin-walled, eight-gallon brewing kettle.

He began by asking where the outlet for the ball valve should be. That was two inches up from the kettle floor, which allows enough room for a siphon tube and a false bottom. (Keg converters will have to measure much higher, above the chime). The next measure was roughly halfway up the kettle, where I wanted to install a half-coupling for a thermometer.

Troy used a water-based marker, then a scribe to mark the metal. A metal punch dimpled the kettle for drilling. He used successively larger drills to make the hole, then did the final sizing with a metal cutting bit and die grinder. The hole for the full coupling was tight enough to support the coupling. The hole he cut for the half-coupling was smaller, only slightly larger than the thread diameter.

Troy fit the coupling squarely into its hole, then “tack-welded” one quadrant to check the placement. Then he did the final weld. He flooded the kettle with argon gas during welding to minimize carbon deposition (without the gas, carbon would build up on the “cool” side, and it’s difficult to clean).

The bottom line: If you can find a good welder, this is your best bet. The parts are cheap and Troy only charged me $25 for labor. You might even convince your welder to work for homebrew! Plus, TIG-welded couplings become part of the kettle structure. If treated properly, they’ll last a lifetime.

Ultimately, the choice depends on your tools, skills, finances and time. No matter which method you choose, you heard it here: Put a spigot in your kettle!

Thom Cannell is a homebrewer and writer in Lansing, Michigan.

NO WELD, NO WORRIES


If you don’t want to weld, or need to quickly add a ball valve to your kettle or sparge-water pot, the Fermentap weldless kit is a great alternative. And it only costs about $18.

Installing this weldless ball valve couldn’t be easier. Drill a 9/16-inch hole in your chosen location, insert the ball valve with the O-ring outside the pot, attach the nut on the inside, and tighten the nut enough to lightly compress the O-ring. That’s it. Fermentap uses a special heat, flame and UV-resistant O-ring. And they’ve treated the brass parts to remove any surface lead.


Fermentap recommends sanitizing your ball valve before every brew session by boiling everything but the O-ring. Leave the ball valve half open, so there won’t be any leftover wort inside. Another note: If you have a thick-walled pot, this fitting might not be deep enough to go through the wall and show at least three threads, the minimum required for connection.

Call Fermentap at (800) 942-2750 or (925) 671-5386. E-mail: info@fermentap.com. Web: www.fermentap.com.