Stainless Steel Auto-siphon: A novel approach to priming a siphon

My path into homebrewing is a familiar tale. I started brewing in a single pot, which slowly over time morphed into a three-pot, fly-sparge system for 10-gallon (38-L) batches. I call a modified stainless conical fermenter my own. The system benefits from a wide range of Brew Your Own magazine projects and hacks, like etched volume markings in the kettle, silver soldered tri-clamp flanges inserted with a homemade dimple tool, wig-welded tri-clamp flanges for the conical, and temperature probe made from a Corny keg dip tube. The technique for the temperature probe came in handy for the motorized mash stirrer with PID temperature controller for the induction heater as well. The copper immersion chiller was a very nice build as well.

After all the upgrades of my brew system I found more and more parts had to be carried from the basement upstairs every brew day and more parts had to be cleaned as well. The perfection of the system led unwillingly to a brew day that had to be planned way too long ahead to fit in our family’s schedule and therefore had me brewing less often.

When I read the BYO article on small-batch brewing in the May-June 2021 issue I realized that brewing smaller brew-in-a-bag (BIAB) batches in-between the big brew days would be the perfect middle ground for my lack of time. The 47-L (12.4 gallon) kettles I own are not practical to use on a kitchen stove, and therefore I purchased a 25-L (6.6-gallon) pot to brew BIAB batches.

I decided I would not want to add any valves to my small pot so I wouldn’t have to worry about seats or sealings or drilling holes (which I had been through a lot). Siphoning the wort out of this pot is no problem at all.

The polycarbonate auto-siphon I own made me often wonder if there wouldn’t be a stainless version. So after having learned so many metalworking skills due to the previous DIY projects, I decided to build a stainless auto-siphon. I really admire the ingenuity of some of the stainless racking canes/auto-siphons out there for reasonable prices. But here in Germany availability of new products is an issue and when you have an itch for DIY equipment, I think it’s rewarding and a lot of fun to innovate.

Since this auto-siphon build is all stainless steel it is therefore resistant to heat, breaking, and certain disinfectants, which polycarbonate is not. And it can completely be taken apart for cleaning. My initial plan for my BIAB system was to have fewer parts to clean. Oh well, at least I’m underway to spend more time brewing.

Tools and Materials

• 0.5 m (1.6 ft.) 12-mm (1⁄2-in.) OD stainless steel tube (or whatever length seems appropriate for your vessel)
• 1 m (3.2 ft.) 10-mm (3⁄8-in.) ID silicon hose
• (2) ¼-in. stainless steel outside threaded end caps
• (1) ¼-in. stainless steel coupler, 1 in. (2.5 cm) long
• Button washer head screw M4 x 10 mm
• Silver solder, solder flux, and solder torch
• 1-mm diameter stainless steel welding rod ~5 cm (2 in.) long
• 4-mm (5⁄32-in.) metal drill bit, oil, drill (drill press preferred)
• Die grinder and sand paper