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Old 07-16-2013, 04:25 AM   #1
Jan 2010
Falls Church, VA
Posts: 107
Liked 13 Times on 8 Posts

Inspired by all of the topics in


I built an insulated plastic conical fermenter.

- Purchased inductor (MDPE cone) and stand from RuralKing
- Use old Home Depot mash tun as cooler to store ice (I use a bigger 70 qt rectangular cooler for 10 gallon batches)
- Used aquarium temperature controller, hobby box, small thermister from DigiKey (that fits in a thermowell) that I soldered to a mono audio cable with leftover wiring to build a simple temp controller.
- 25 ft stainless steel wort chiller to immerse in fermenting beer
- Use pump that came with Mark's Keg Washer (simple pond pump) to recirculate ice water through beer during fermentation.
- 1/3 HP pump with CIP spray ball on camlock. Use Iodophor to sanitize before pouring wort, and PBW to clean up system. The CIP is only used for cleanup and santization, but removed during fermentation.
- A 3/4" triclamp elbow is used to recirculate cleaner sanitizer, and as a blowoff tube. I sealed with silicone and weather stripping so that I can fermented with blowoff, but also maintain pressure of a few PSI inside conical (see photo of homemade spunding valve)
- Homemade spunding valve also has ball lock gas post so that I can top off CO2 after dumping yeast, or when I have extended primary on a lager and want to be paranoid.
- Simple insulation from Home Depot duct taped.

I use lots of ice via pump to chill beer to pitching temp, dump trub, aerate, then pitch yeast. To maintain temps, I change out frozen 2L bottles of ice once or twice a day, depending on the activity of yeast.

The bling factor of this build was the stainless triclovers. However, if I ever upgrade to a stainless conical, the fittings are fully translatable. I've been so happy once I got this set up, my interest in a stainless system has diminished; this fully temperature-controlled system with spunding was cheaper than a barebones stainless conical without fittings like the Brewhemoth or Blichmann. Plus I can really see when the CIP cleans out all krausen lines with the large lide opening, and fully disassemble, clean and sanitize threads and parts. If I ever had problems with the plastic cone, the replacement is a mere $60 and very briefly drill holes again.

To install the side pickup, I used a Viton gasket insead of normal EPDM or Buna-N since it's immersed in beer. Otherwise it's all silicone, stainless, and the plastic conical.

Doesn't hurt that the outside is covered in insulation. During parties, nobody suspects it's plastic until I tell them.

Beers fermented so far (all 10 gallons):

- IPA, Chico at 66 F
- Kolsch, WY1007 at 60 F
- Oktoberfest (in progress) at 50 F, while my house is 74 F in July (notice the temp controller hovering near 10 C, this is after 36 hours with active fermentation inside)

You could tell I was getting progressively confident with the fermenter's temp control abilities.

If anybody's considering a conical, think about building a plastic one. It's easy to drill plastic, plus the insulation is the real key to excellent temperature control without buying a second large freezer. I think it's more efficient to transfer energy directly into the wort rather than the surrounding air. During active primary with yeast swimming around, I think it's especially efficient to avoid any temperature gradients.

I like the conical for:

- Dumping trub in the fermenter
- Giving friends viable yeast from a recent batch (I normally propagate my own with different strains between batches)
- Bulk fermenting 10 G at one time, instead of two carboys
- Filling two cornys with the side pickup at the fermenter rather than moving the fermenter(s) around
- Less left-behind waste in the fermenter, I leave behind just about a qt of material below the side pickup.
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Old 07-16-2013, 07:20 AM   #2
Nov 2011
Visalia, CA
Posts: 740
Liked 173 Times on 119 Posts

What did you use for dip tube?

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Old 07-16-2013, 11:23 AM   #3
Jan 2010
Falls Church, VA
Posts: 107
Liked 13 Times on 8 Posts

I built a diptube by cutting a stainless steel elbow installed in a compression fitting, but never used it.

The dead space below the side port diptube only holds about a quart based on where I drilled it, and is usually full of yeast, dry hop matter, etc. I think a diptube is only necessary if the side port is far higher up the cone, because I'm happy to leave some of that stuff behind.

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Old 07-18-2013, 12:22 AM   #4
Senior Member
cfrazier77's Avatar
Mar 2011
Troy, IL
Posts: 670
Liked 96 Times on 66 Posts

Nice build. I noticed your capabilities to add pressure. How much can it hold?
Happy Dog Brewing

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Old 07-19-2013, 05:51 PM   #5
Jan 2010
Falls Church, VA
Posts: 107
Liked 13 Times on 8 Posts

Before I only tested to about 3 PSI. With this lager, it's at atmospheric pressure, aapparently the seal has failed.

The silicone and and weather stripping are only protecting against inadvertent dust floating in.

I contacted 'allclene' from the original thread, and he estimates finishing at 10 psi in there.

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Old 07-31-2013, 03:06 PM   #6
Dec 2010
Berwyn, PA
Posts: 375
Liked 63 Times on 45 Posts

I see you got the Oktoberfest down to 50 degrees. Have you been able to hold that temp?

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Old 08-07-2013, 12:44 AM   #7
Jan 2010
Falls Church, VA
Posts: 107
Liked 13 Times on 8 Posts

Originally Posted by FreddyMar3 View Post
I see you got the Oktoberfest down to 50 degrees. Have you been able to hold that temp?
I held it for 6 days, until it attenuated 75%. Let it rise to 60 F, which required half the amount of ice to maintain temp.

Dumped trub/yeast once it finished primary, lowered temp, and they've been lagering in kegs for a long time, and will continue to until October.

I could tell when they reached final gravity when temp control would lower it substantially since the only heat was from ambient, not internal fermentation.

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Old 08-08-2013, 03:57 AM   #8
HerrMunich's Avatar
Feb 2013
Berkeley, CA
Posts: 15

This is an amazing build - great stuff sir! You have all the bases covered - pumps, immersion chiller, temperature control, shiny triclovers, etc

I had a question about how you purge the trub before pitching, and how you extract the flocculated yeast. Is it as simple as...opening the valve a bit, and shutting it once clear wort starts coming out?

I also had a general question about thermowells - is it basically just a hollow stainless tube, with one end sealed off - and you thread the temperature probe down to the bottom? And thus the probe measures the "air" temperature at the bottom of the tube, which is ideally a good approximation of the temperature of the wort?

Also: I don't see a valve on the side pickup. Maybe it's there, and I'm just not good at recognizing triclover clamps/connections, or is it not present in that picture?

Sorry for all the questions Again, insanely cool and inspiring build!!! You really got the gears turning in my head, heh.

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Old 08-08-2013, 12:22 PM   #9
Dec 2012
Posts: 434
Liked 40 Times on 19 Posts

So, the million dollar question: How many dollars did this cost you to put together?

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Old 08-08-2013, 12:41 PM   #10
Jan 2011
Lake Park, MN
Posts: 57
Liked 5 Times on 3 Posts

Looks good! its amazing how good just using ice in the home depot cooler works! 50 degrees!

Im actually looking at doing DIY temp control for all our nanobrewery fermenters that are 60 and 100 gallon. im also looking at using stainless steel coil for an immersion coil system.
I see you have a bunch of plastic bulkheads at the top to plumb in the chiller and thermowell, are those just compression fittings i see used to seal things up?

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