Build a Peristaltic Pump

Like many brewers, I have the occasional need to move liquids from one place to another (transfer wort from kettle to fermenter, or rack from fermenter to keg, etc.). There are many pumps on the market that can assist in moving liquids from place to place. Most of these pumps, such as the March or Chugger pumps are “centrifugal” pumps, which use a rapidly spinning impeller to push liquid from place to place. These pumps are great, but they have three significant drawbacks for how I want to use my pump: They require priming (meaning the pump head needs to be filled with liquid before you turn on the pump); They aren’t very portable (most brewing pumps run on mains voltage which makes it difficult to use outdoors); and they can be expensive. For occasional use, it is hard to justify that sort of expense to my non-brewing significant other.

If I could add a fourth issue, it would be sanitation. Those fancy pumps are opaque and full of little nooks and crannies where spoilage organisms could hide. That’s not an inherent weakness if you maintain proper sanitation, but I know people, and people are lazy.

So, how does an enterprising brewer solve these issues and move 6 gallons (23 L) of hot wort around? A peristaltic pump!

Peristaltic pumps are great because they don’t require priming. They can actually pull liquids up out of a carboy, kettle, or keg, instead of needing gravity to prime. A peristaltic pump can also be driven by virtually any motor. In my case, I use a drill. This way, I can brew outdoors. Peristaltic pumps are also cheap to construct and simple to sanitize. In fact, the pump itself never touches your precious beer, only the silicone hose does, which you need to clean and sanitize anyway.

Peristaltic pumps work by occluding (squeezing) a section of tubing, and moving that occlusion around the body of the pump, pushing along a volume of liquid, and pulling in the next slug of wort. For more information about how they work, check out the Wikipedia article on peristaltic pumps (https://en.wikipedia.org/wiki/Peristaltic_pump)

Now, let’s look at how we can make one of these wondrous liquid moving marvels for ourselves.

** Safety note: With this project, you may be pumping around very hot liquid. Don’t use a ball valve to control the flow from your pump, because the silicone hose can soften with heat and cause the hose to slip from the barb, spraying hot wort all over the place.

Materials and Tools

9.5-inch (24-cm) springform cake pan
(4) 2-inch (5-cm) casters
5-foot (1.5 m) silicone hose (1⁄2-inch ID, 3⁄4-inch OD)
Scrap piece of hardwood (~3 3⁄16-inch square, 1 1⁄2-inch thick)
(2) 1-inch or larger washers
(2) 1⁄2-inch washers.
(2) 1⁄4-inch -20 T-nuts
(2) 1⁄4-inch -20 nuts
1⁄4  x 3-inch – 20 bolt
(8) #12 3⁄4-inch wood screws
Zip ties
Hammer
Compass
Drill and bits
Dremel tool or similar with grinding stone and cutting wheel
7⁄16-inch socket/ratchet and wrench
Screwdriver
Framing square
Saw