Friday, December 24, 2010

How to make a Conical Fermenter - DIY Tutorial

Dec 24th 2010

   We'll I posted previously about how much it would cost to build a conical fermenter. Since then I was able to get all the supplies I needed to build the Polyethylene Inductor Tank Conical Fermenter. It was actually very easy. I even took pics of the project from start to finish so that you could get a real feel for it. Lets start with what parts I needed and what I did with them.

   I got the 14.5 gallon inductor tank that already had a screw on lid and also a 1.5 inch threaded plug. This made is much easier to add the ball valve to the bottom because 1.5 inch is a standard plumbing size. I bought a 1.5 inch male fitting, 1/2 inch female fitting, and a 1/2 male ball valve. I also got three 4" casters wheels for the stand. The  casters have a threaded bolt that is 3/8 inch which matched the bolt holes already in the stand.

Delivered!   Unwrapped!

 Stuff I needed.

It rolls good. This will help when moving it while it's full. I brew in the garage and ferment in the house.

   The tank comes with a plug. Take the plug with you to the hardware store so that you can get the fitting that you need. Pick up a Ball valve while you are there. You'll also need some PVC primer and Blue Glue.

   The PVC Primer and Blue Glue are a 2 part type of glue that is similar to a plastic welding process. When the PVC Primer is mixed with the Blue Glue it will harden and weld with the PVC.

   Put all your fittings and ball valve together. You'll need to apply Teflon tape to the ball valve threads because it's metal. Use a lot of Teflon Tape. Normally you want to do at least 3 layers of teflon. However some experts will go with more. I've had luck with 3 layers so I use it, but if I'm worried at all about the surface condition of the threads, I'll add a couple of layers. You'll never want to use less than 3 layers.

Take the plug out and insert the modified ball valve assembly. Looks Good, Feels Good.

 Once you're confident that you got the seal right fill it with water and test your work. I'm testing mine in the shower for a few days with tap water.

   So far I have successfully added the Yeast dump valve and the casters. Still to do is adding a racking valve, gasket for the threaded lid, and a hole for the Air Lock. Since I have 2 weeks before my next brewday. I'll focus on those things next weekend.
   When adding any thing to your fermenter, you'll want to go with a weld less fitting. Drill a hole just slightly larger than the weld less fitting. You should be fine.

Dec 27th 2010

   Ok, I got around to finishing up the racking valve. Here's a photo. This valve will be connected to a hose for filling bottles and kegs so there is a barb on it. Since this is all custom work I recommend that you customize yours to what ever equipment you have. I use a small barb for small diameter ID hoses, just because that's what I prefer, and it's easily adaptable. Go with what you like.

Jan 9th 2011

   I decided to place a temperature controller on this fermenter. By doing this I don't have to turn the heat on in the house while no one's home. This heating pad lines about 25% of the exterior of the fermenter. I have also ordered an On/Off Switch Temperature Controller with temperature probe. The Temperature controller will turn the heating pad on when the temperature gets too low and off when it gets to the right temperature. This will allow for better control over the fermenting process.

Jan 13th 2013

   Time flies. I still use this fermenter for brewing and it still gives a very good beer. Kevin recently purchased a stout stainless steel conical fermenter for his brewing process. It's a gorgeous 14 gal fermenter. I like how it looks, but I just can't justify upgrading when this one works just as good or maybe even better.
   Of course the poly ethylene is much softer than 304 stainless steel so I have to be very careful not to scratch the inside while cleaning it. If that's a concern of your's I would definitely pay the extra few hundred $$ for the steel fermenter. Another drawback to the steel fermenter is that the stand does not readily accept casters, so you have to weld or rig up something if you want rollers. The steel is a bit heavier but when either of these fermenters is full they are pretty much, equality hard to move around.

   For comparison I've added this photo of the Stout Conical Fermenter. This is a well made inexpensive fermenter that's made in China. You notice that is doesn't have any holes on the legs to mount casters, so if you want them you'll have to make a bracket drill some holes and bolt it on, or weld them on.

Image taken from


   This fermenter also has a thermometer mounted on it. If your using a temperature controller then you'll already be monitoring the temp with the controller, however it's always nice to have extra temperature monitoring. All of the valves and thermometer have hardware holding them on that is completely removable and cleanable. You can also order parts for everything from Stout. 

   Of course I'm only discussing this in comparison to the Polyethylene that I build before. Between Kevin and I we've brewed at least 50 times using the Polyethylene fermenter and it still provide consistent good tasting beer. I will Post on here as soon as it dies. 

   This is something that you should never have to worry about using a stainless steel fermenter, as you can clean it as hard as you want with severe cleansers and the steel should hold up well. Although I've read that you should not use highly concentrated bleach on 304 stainless because it may cause pitting. With Polyethylene you must to use mild detergents.  


  1. Great tutorial! I'm curious about how the racking valve is attached to the fermenter. Did you thread in a coupler?

  2. Thanks for the praise. I welcome any feedback, especially the good. It sounds like you're already set on the conical, but whether to go with the polymer or the stainless steel? Me and Kevin have been putting this conical to good use over the past year, and it's held up good. Still doing what it needs to (making good beer). Stainless Steel is like the beer brewers diamonds. It's forever. Going back to your question... The racking valve uses the standard weldless fitting that most brewing kettles use. The valve itself has threads and it has an O-ring that makes the seal between the side of the fermenter and an appropriate nut. Research "Weldless Fitting." I prefer these as you can take it on and off, replace it, clean it, and use it for something else, whenever.

    I got a chance to read your Hard Apple Cider Blog. Looking forward to your future postings.

    Travis L.

  3. Thanks for the speedy reply! I wasn't really expecting a response since this post was so old. I figured you were either using a weldless fitting or you threaded something into the plastic with plumbers tape. Thanks for the heads up!

    I've looked into stainless conical fermenters and found some for around 300, which is a total steal!

    That being said, I really like the whole DIY thing. If I can save a little money and learn a new skill or two, I'll probably go for it.

    I have been considering creating my own conical out of sheets of stainless but I'm not sure if it's cost effective of if someone like me can even pull it off.

    Otherwise, simply going with an inductor tank will probably be fine. I've heard rumors about vintners switching to HDPE over barrels for fermentation and aging. I believe stainless will the brewer's diamonds as you said, but if I can make 2 or 3 plastic fermenters for the price, I'm going to take that route.

    Thanks for checking out the AppleLog, I haven't updated it in a very long time. I was supposed to follow up with a couple of orchards to help pick the last fruits of the season but totally dropped the ball. I switched to using AJ concentrate for the winter, and I'm still pretty pleased with the results.

    Thanks again for your help! Brew On!

  4. My only concern is the metal used in those valves. Have you had any problems with off flavors?

    1. That's a good question. I'm really careful about the hardware I buy, Not all metals are created equal. That's one of the reasons brew kettles are expensive, it's the alloy used (usually 304 or 316 stainless steel), which is high in Chromium, Nickle and other high-priced ingredience. Make sure that you buy valves that are made for plumbing/water they're made of brass and steel. You should be ok with that. If your really concerned you can always look for stainless steel 316 valves, but my plain old brass ones work just fine. No off flavors associated with them.


      PS Just got done brewing a Honey Ale. Wanted a Blonde but the OG was too high, 1.071. I'll just have to call it something else.

  5. Excellent article. Thanks for the awesome idea!

  6. Hey, I saw this late last year, and it gave me the inspiration to do the exact same thing.
    I got the same rotomold tank from spraysmarter, added a few fixtures from Lowes, and built a stand from wood. It came out well. Just tasted my first batch of beer from it (stout) - it also came out well.

    I cheaped out and used plastic shutoff valves, they work, but they kind of stick when not in use for a few days, so if I did it again, I'd spend the extra money for the steel/brass valves...maybe I'll change them at some point.

    anyways, thanks for the idea, and the instructions, it worked perfectly for me.


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  9. I purchased a Roto Mold 30 Gallon to do this same thing. How high did you mount your racking valve? Did you do an inside tube attached to the fitting or just use the opening as is?
    How often do you tear it down and deep clean it? I keep reading folks having infection issues and blame it on "cheap porous plastic" but I really believe its the brewer's sanitation practices. The more nooks and crannies you put in place, the more religious and prudent you need to be in cleaning.
    How's your track record been with these now that it's been many years?

  10. I took a stainless bolt (aboug 3 gallons from the bottom) (on a 150 gallon plastic conical), drilled a hole through the center of the bolt, and placed it facing outward with an o-ring around the head. With a nut on the outside pinning it to the tank side. Then machined the end of the bolt to accept camlock fittings. All food safe, no spots for bacteria to hide.


  11. What capacity is this? It doesn't say anywhere.

    Also does the stand come with it or does it cost extra?