Spunding/Co2 process

[renstyle]

...
The kegs in the fridge have a floating dip tube. The "in" posts (CO2) from both kegs are joined by a nylon barbed T fitting, which leads to a plastic T carbonation cap (thanks @renstyle for that recommendation) attached to a 2L bottle. The out of the bottle goes to the out side of a keg (so it fills with gas from the bottom). The "in" side of that keg goes to another keg set up the same way. The "in" side of that keg is fitted with a Blowtie.

I've only done this once before with a lager strain fermented at ale temperatures. I remember filling the keg pretty full but didn't have any blowoff. Samples of the beer were pretty tasty, no off flavors detected. Fermentation was done in about a week.

This weekend was the first time using ale yeasts. I need to figure out a better way to manage blowoffs because right now it's looking like I'll need to re-sanitize the first empty keg. I didn't have the tubing suspended initially like the pictures below show but I think that might have helped if I had done that from the get go. I would have thought that the "blowoff bottle" would have filled up before going up the tube into the keg but that didn't seem to be the case.

Anyway, initial thoughts are that it's a neat system that I'll definitely stick with for lager strains, and if I can figure out a good way to better handle blowoffs I'll do it with ales too.

Nicely done. Had a question about your blowoff bottle setup... Do you have any tubing inside the 2L bottle connected to either of the carbonation caps?

When I run a bottle like this I have some 5mm-I.D. EVABarrier tubing (no clamps needed) running from the top-most carb cap to near the bottom of the bottle. The bottle is filled with enuf vodka to submerge the tubing near the bottom of the bottle, maybe an inch or 2. That way, in addition to catching any blowoff, it gives me fermentation feedback (bubbles).

The "side cap" is used to send the excess CO2 into the serving kegs.

In my setup, I do not harvest yeast from the blow off, so having vodka/StarSan/plain water in the bottle is OK for my needs.

I can see how leaving the bottle mostly empty will get you to the same place, just with no bubbling. I hadn't considered that previously, but it's a good idea.

 

[renstyle]

How much headspace did you have in the fermentation kegs? A little more space and some Fermcap might help with the blowoff issues.

Doing a pressure fermentation in a corny I get it pretty full, 18L (4.76gal). That leaves a bit over 2L of headspace in a standard corny keg. It's tight, but with Fermcap+pressure it really helps keep the krausen calm.

 

[Cheesy_Goodness]

How much headspace did you have in the fermentation kegs? A little more space and some Fermcap might help with the blowoff issues.

I didn't measure it but it was probably an inch or two below the CO2 dip tube. There wasn't much room. Never used Fermcap but it might be worth giving it a try. There wasn't much blowoff though all things considered. About half of what's in the bottle was Starsan. The stuff that made it in the tube past the blowoff bottle was probably a few ounces at most.

Nicely done. Had a question about your blowoff bottle setup... Do you have any tubing inside the 2L bottle connected to either of the carbonation caps?

When I run a bottle like this I have some 5mm-I.D. EVABarrier tubing (no clamps needed) running from the top-most carb cap to near the bottom of the bottle. The bottle is filled with enuf vodka to submerge the tubing near the bottom of the bottle, maybe an inch or 2. That way, in addition to catching any blowoff, it gives me fermentation feedback (bubbles).

The "side cap" is used to send the excess CO2 into the serving kegs.

In my setup, I do not harvest yeast from the blow off, so having vodka/StarSan/plain water in the bottle is OK for my needs.

I can see how leaving the bottle mostly empty will get you to the same place, just with no bubbling. I hadn't considered that previously, but it's a good idea.

Definitely should have used a piece of tubing on one of the caps! I'll do that next time, thanks for the tip(s)

I did notice this morning that if I have two beers connected to this set up like I show in the pictures, it is possible for blowoff from one keg to get into the other keg if one batch takes off faster than the other. I don't think it will really matter much since they're both actively fermenting but it is something to consider.

 

[Transamguy77]

@Cheesy_Goodness glad to see you back! I’m going to subscribe to this because this is what I want to do also. And when I finally get around to brewing again I’ll post back and let you know what I did and I’m sure you’ll do the same.

 

[DuncB]

Damm wrote this yesterday and forgot to press post.

I use the bottle for blowoff capture and depending on volume sometimes just attach the spunding valve to it. I don't put any liquid in it as a bubbler because you can harvest top crop yeast if you have a very sanitised bottle. Then swap it out later.
I don't tend to start flushing out and purging kegs until after the krausen has fallen, there's plenty of gas made after krausen. Just keeps it all a bit tidier.

Video only taken with bottle lying down for convenience of imaging, normally upright.

 

[tieflyer]

Ok, I have a 7 gallon fermonster plastic fermentor. I saw in a pic in post # 6 here where
DuncB maybe using a fermentasaurus pressure kit instead of a fermentation keg. I was wondering if i could use this kit with my fermonster?

 

[DuncB]

I'm not sure how much pressure a fermonster can take, but can't be much pressure to force the krausen out so could get into the collecting bottle.

 

[Elric]

I'm not sure how much pressure a fermonster can take, but can't be much pressure to force the krausen out so could get into the collecting bottle.

fwiw

I started to pop the base molding out at around 20psi on a one gallon fermonster. 5-10 psi can be easily held.