Archive for October, 2011|Monthly archive page

20 gallon boil kettle / Electric BIAB kettle

Monday, October 31st, 2011

After years of drooling over other peoples kettles I’ve finally acquired a big stainless brew kettle. No more plastic boiling vessels for me, and I can finally make my electric brewing rig look good, work well and allow for easier cleanups.

I’ve already drilled a 32mm (1-1/4″) hole with a step bit for the 5500w heating element I will be using. I had read reports, for example on Kal’s site about step bits being unreliable for big holes like these, but I had no issues whatsoever. I just used alot of cutting oil/grease and made sure to keep the battery drill steady and the hole came out very nice I dare say. I also drilled another 22mm hole to accommodate a 1/2″ 3 piece stainless steel valve from bargainfittings. I also got a pickup tube with the valve. Here’s what the pickup tube and heating element look like installed in the kettle.

The 3 piece ball valve is connected to a Tee, where the pt100 temperature probe is. Next in line is the pump, which is used during mashing and cooling. More on that later in the post. I have a couple of reasons why I wanted to mount the probe outside the kettle, inline with the pump. First was that I didn’t want to drill another hole into the kettle, and wasn’t sure what placement of the probe would be best.

The kettle has a false bottom, that sites roughly 8cm above the bottom of the kettle. The false bottom is 45cm diameter and was laser cut for me by a friend.

My usual brewing process goes something like this:


  1. Heat up mash water, with false bottom in the kettle and pump running (otherwise the temperature probe would be useless)
  2. Measure and mill grains, using a rather fine crush
  3. Put the grain bag into the kettle, add grains and stir well to dissolve any grain clumps
  4. After 60 minutes mash I do a mashout at 76°C for 10 minutes. It takes about 10 minutes for the temperature of the mash to rise

While mashing the pump is on, recirculating the mash water and ensuring even temperatures throughout the mash. The PID controller keeps the temperature constant within about 0.3°C.


  1. After mashout I pull the grain bag out and hang it up to get as much sweet, sweet wort as I can out of the grains
  2. I remove the false bottom and put the heating element to work. It takes me about 5-10 minutes to reach a boil from mashout temperature
  3. I boil for 60-90 minutes depending on recipe, adding hops, irish moss and other additives as needed
  4. When there’s 15 minutes remaining I connect the already clean (but not sanitized) counterflow chiller (CFC) and recirculate boiling wort through it to sanitize it
  5. At the end of boil the heating element is turned off, wort is pumped through the CFC and chilled. The wort is at pitching temp when it exits the CFC so it goes straight into the fermentation bucket(s) and the yeast is added. This step usually takes about 10 minutes.

So that’s a typical brew day for me using my shiny new kettle. I’d love to hear about your brewing systems in the comments!

Next post I will write about the control box I’m using to control the element.