The Amazing Thermosiphon Reboiler Brewing System

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Our approach to scaling up the brewing process

It's been said that you know you're a homebrewer when you think that ten gallons is not a lot of beer. Well, after nearly a decade of brewing, I discovered it's true. When you keg up 5 gallons for a club meeting, give away a case of bottles to friends and then hold aside some bottles for competition, you suddenly find yourself asking, "Where's MY beer?" We've brewed a couple of batches doing a two kettle boil, but that is a pain in the keister. So we set out to build a larger system.

We started out buying a converted keg with the top cut out. This holds 15 gallons and makes a great boiling kettle. Of course, it's too big to fit on the kitchen stove, so we had to get an outdoor burner and a brewstand. When we designed the setup, we developed a couple of ground rules: The system must not require lifting of anything more than a few gallons, and the system must be portable. No lifting means that the system either needs to be gravity fed, or needs a recirculating pump. Portable means that the stand has to be collapsible. Finally, we needed a way to heat a lot of sparge water. Some people use a second converted keg and move the burner to an upper level. Some people buy a pump. We chose a different approach: Get a second Gott cooler and heat the water with a thermosiphon reboiler. Here is how it all looks.

12 gallon brewing sustem Boiler Tubes The Reboiler

The reboiler works on the same principle as a coffee percolator. Water is heated in a set of copper pipes inside a stovepipe. Water inside the tubes quickly reaches boiling. The bubbles rise upward, pushing liquid out the top. The water is replaced by cooler water from tubing connected to the bottom of the sparge water tank. The whole thing is mounted on top of a burner. We hooked it up to run off of either natural gas or propane. The reboiler is brazed with copper-phosphorus alloy in the flame area, and tin water-pipe solder every place else.

Taking apart stand Collapsed Stand

The stand is made from copper water pipe and plywood. We used floor plates and unsoldered adaptors to put it together. The tubes easily come out of their sockets allowing the whole stand to collapse.

Water getting hot Ready for mashing

Here you can see the steam bubbles as they return to the sparge water tank. We use the reboiler for two steps: Initial mash-in and for sparging. The insulated Gott cooler keeps the water hot throughout the mash process.

Boiling the wort Boiling the wort Steam from the boiling kettle

Once the sparge water is hot, the reboiler is done. We take it down and put the boiling kettle on the burner. Once the wort is running clear, we start the sparge water flowing and collect the runoff in the boiling keg.

chiller by pot Chilling the wort Chilling the wort

After the boil, we cool the wort. I had to modify my chiller to fit the new boiling kettle, which is taller and has a smaller opening than my 30 quart pot. Fortunately, it has plenty of capacity to chill a 12 gallon batch. The entire batch is cool in 15 minutes.