Speidel Fermentation Conundrum - no bubbles from blow off tubes

[sminar]

I'd love some input from experienced brewers!

I'm a fairly new brewer. First batch at home was July 2016. Started with a 6 gallon bucket for my fermenter. Switched to glass carboys soon after for better observation of fermentation. At about 10 batches, I got tired of slippery glass (worried about dropping/breaking, tired of trying to get my stopper to stay in). A bit of research led me to buying two 30l Speidels.

I outfitted them with Jaybird's / NorCalBrewing blowoff tubes with thermowell and Speidel chrome spigots. My typical batch is about 6 gallons so there's plenty of headspace.

I use an Inkbird to manage fermentation temperature in an upright freezer. The sensor is installed in the bottom of the thermowell (well under the surface of the fermenting beer).

I learned early that the temp differential in my ferm chamber was significant when the fermenters were shelved vertically, one on an upper shelf, one below. So I place them side by side on an upper shelf (tight fit).

I use 1/2" silicone tube on the blowoff tubes and run them into StarSan in a two gallon bucket on the bottom shelf of the fermentation chamber.

I attached a pic (~ 12 gallons of Caramel Amber Ale split between the two fermenters, 1.75 days after pitching).

My last 3 brews have been ~11 gallon BIAB batches split into the two Speidel fermenters. The first was a Fat Tire Amber Ale clone, the 2nd was a YETI Imperial Stout clone, the 3rd and current batch is a Caramel Amber Ale.

Here's the conundrum: I never see any CO2 blow off / bubbles in my setup!

• I'm always overpitching my yeast by a small margin.
• I've always observed Krausen being formed.
• I believe I'm smelling CO2 / appropriate fermentation odors.
• I've lightly pressurized my Speidels and observed no leaks and I've never had signs of leakage at/around the spigot and top (including using StarSan to look for bubbles)
• I've tried switching to a small cup of StarSan and putting the cup just below the height of the blow off tube.
• I've so far always hit my expected FG and the beer tastes awesome!

I can't explain it. My understanding is the volume of CO2 produced by fermentation is surprisingly large. Fermentation has been successful so the CO2 must be going somewhere. The resulting beer doesn't seem carbonated at all when I keg it.

I've considered switching to an airlock to minimize the backpressure as a test, but I'd have to give up the thermowell to do it. Perhaps I'll try that on one of the two fermenters for my next 10+ gallon split batch.

Any ideas? It's got me puzzled.

 

[dthompson79]

There is a leak somewhere. For those blow of/thermowells are you using the silicone gaskets NORCAL had made for these? Is the O-ring under the spiedel lid? That is the only 2 places you could have a leak. Gotta be one of those

 

[popsicleian]

There is a leak somewhere. For those blow of/thermowells are you using the silicone gaskets NORCAL had made for these?

That's what I was going to say. I used to have the exact same problem until I got some of those silicone gaskets. They're great.

 

[sminar]

Thanks for the brainstorming!
The o-rings are in place under the large lid. Carefully tightened.
I have been placing the small o-rings between the metal blowoff and the Speidel. I try to be uber careful when tightening, but it's one of my suspect leak locations.
The o-ring behind the spigot is reasonably well captured buy the spigot plastic "shelf/groove", but I'm also very careful to place and hold the spigot on the Speidel while installing and tightening.

I ordered the new silicone gaskets two days ago!

I suspect they will solve the problem, but I'm baffled by the fact that I can pressurize without leaking, I get no bubbles at the obvious leak spots and minimizing the blowoff pressure didn't produce bubbles. In the past, I was always able to squeeze the blowoff tube and see bubbles come out.

The good news is... no contamination / lost batches so far

 

[BrunDog]

You don't need a blowoff for those fermenters and volumes unless you are doing a fresh hefe. You can use the air locks comfortable from the beginning.

That said, I am not familiar with the NorCal upgrade. Does it allow for the airlock? If not you would be giving up the thermowell, so that is probably not something you want to do.

 

[raysmithtx]

I had exactly the same problem with the NorCal modified lid. Finally traced it to the seal in the cap. When they cut the hole in the cap for the stainless steel plate with the tube attached, the seal no longer has the lip on the inside to hold it in place as you tighten it. I found that a P trap gasket from Lowes fit exactly inside the cap (with the round part sitting on top of the gasket). I think it cost $1.19 for a 2 pack. It made the seal much tighter and I once again had airlock activity once I installed it.

Hope this helps.

 

[sminar]

@BrunDog - NorCalBrewing didn't offer a solution for thermowell and airlock at the same time when I bought in early fall. They now offer a thermowell / pickup tube combo I could use to replace the spigot. Would also require a ball valve (which I'd prefer anyhow). Slight issue with the design as the thermowell opening gets blocked by the ball valve/mount, making insertion of the probe difficult once the valve is installed. I agree I can do without the blow off tube. I chose that as the simplest solution for me to get the thermowell, have the blow off just in case and fit in my ferm chamber w two fermenters, one above the other (obsolete need for now).

I did buy an extra couple of lids and I have some thermowells. I may drill and gasket one of the lids and give it a shot.

I think for my next batch, I'll have the new gaskets from NorCalBrewing and I'll setup one fermentor with the blowoff/thermowell and one with the airlock. I've been switching my probe from one fermenter to the other out of curiosity, but the temps are staying within one degree of each other for same wort / same yeast.

@raysmithtx - great find on the P trap gasket. I'd follow your lead, but I did order the new silicone gaskets that NorCalBrewing produced. They should be here in a couple of days. They slip over the edge of the circular metal plate, making it easy to ensure they stay in place and make a good seal.

 

[drgonzo2k2]

Personally I really love NorCal Brewing, I'm super happy with lots of equipment I've purchased from them. Their custom false bottoms are just incredible; however, I never really fell in love with their Speidel accessories when they came out. Total transparency, I've never tried them, they just didn't appeal to me.

I use SS Brewtech thermowells and rotating ball valves in all my Speidels and could not be happier.

You can install both in a Speidel with a cordless drill in about 10 minutes.

By the way, I do not recommend the Speidel as they are chrome plated, and the interior deteriorated very quickly for me. I was back to just using the Speidel plastic ones until I found the SS Brewtech rotating ones.