Pipe Fermenter

The idea for this unique fermenter project started shortly after I began working for Fermentis yeast company. I had been researching the impact of fermenter shape/design on the yeast and I wanted a fermenter that would simulate the high hydrostatic pressure of a commercial brewery’s cylindroconical vessel (CCV). I remembered some fermenters that the Pilot Brewery at MillerCoors had (where I previously worked), that were shaped in a more pipe-like design and started to think up a way to do something similar at home, with food grade parts. I figured that PVC piping for home plumbing was food grade and already in the correct shape for this type of fermenter.

For those that can’t fit something this size you can keep the fermenter shorter, losing some volume, but allowing for it to be kept anywhere with normal ceiling heights, typically 8 feet (2.4 m). This would allow for a working volume of about 4 gal. (15 L).

Fermenter design/shape does alter the flavor profile of different strains in different ways. It’s interesting to play with the fermenter, like we do with malts, hops, and yeast. This pipe fermenter also saves space since it is only 4 inch (100 mm) in diameter and can fit in any garage, apartment, or small space you have, given the fermenter is short enough!

Step 1. Pipe sizing

By calculating the volume that could be held in a cylinder, I concluded that the best size was 4-inch (100-mm) diameter PVC pipe that would be nine and a half feet (2.9 m) tall. This would give a total capacity of ~ 6.2 gal. (23.5 L), if my math was correct. With the decreased diameter and increased height of the “fermenter”, there is an exponential increase of hydrostatic pressure on the liquid/yeast at the bottom, when filled.

Step 2. Drain Valve Design & Cap

To complete a fermenter, I would need a way of moving the beer and I knew that a siphon was out of the question. I opted to reduce the pipe down to a 3⁄8-inch (10-mm) valve that I could connect a hose to, to drop the beer to a secondary fermenter. This was a little tricky to source a 4-inch to 3⁄8-inch (100-mm to 10-mm) reducer. So I piped together 5 reductions with an elbow, to make it functional. For the top of the fermenter, I used a 4-inch (100-mm), domed pipe cap and drilled a 1⁄2-inch (13-mm) hole that I could insert a stopper and airlock into.

Step 3. Support Structure

Next task was building some sort of contraption to keep it vertical. Again, I had to think of a way to keep the fermenter off the ground and allow me room to transfer the beer, while making sure the fermenter didn’t tip over. I started with a 2×12-inch (5×30-cm) board and drilled a hole for the drain valve. With the reducers having square surfaces for tightening, I could stand the fermenter up easily. Due to the height and high center of gravity, I built a “cage” to hold the structure up and stop it from tipping over. In the end, the fermenter in its entirety, is just over 10 feet (3 m) tall.

Issue: May-June 2018