Spunding

[Jake]

Gave the spunding valve another go and everything was going great until the very end. I equalized the pressure of both kegs around 7psi, with the full keg slightly higher. Everything was going well, I disconnected to shake up the full keg and when I reconnected, the sanitizer from the other (empty) keg flowed into the full keg ... F***

Luckly I sanitized the empty keg really good and put a liter of starsan in there, so it was just a bit of starsan, so I dont think it's going to hurt anything.

So my question is, do I need to keep the full keg connected to the CO2? I'm slightly intoxicated right now, but I don't recall having to keep the full keg on CO2, but looking back it would make sense that the full keg would need to remain on the gas line because the beer would absorb the CO2. So does the full keg need to be on CO2 during fermentation?

Right now I have the full keg's gas port to the empty kegs liquid port, the the valve on the empty kegs gas port. Started with the full keg slightly more pressurized. What am I missing?

Another epic fail by yours truly. Hopefully the beer is fine

[JohnQ]

Gave the spunding valve another go and everything was going great until the very end. I equalized the pressure of both kegs around 7psi, with the full keg slightly higher. Everything was going well, I disconnected to shake up the full keg and when I reconnected, the sanitizer from the other (empty) keg flowed into the full keg ... F***

Luckly I sanitized the empty keg really good and put a liter of starsan in there, so it was just a bit of starsan, so I dont think it's going to hurt anything.

So my question is, do I need to keep the full keg connected to the CO2? I'm slightly intoxicated right now, but I don't recall having to keep the full keg on CO2, but looking back it would make sense that the full keg would need to remain on the gas line because the beer would absorb the CO2. So does the full keg need to be on CO2 during fermentation?

Right now I have the full keg's gas port to the empty kegs liquid port, the the valve on the empty kegs gas port. Started with the full keg slightly more pressurized. What am I missing?

Another epic fail by yours truly. Hopefully the beer is fine

Check Valves, they're $3, work like a charm. Pressures can fluctuate as you do stuff and there's no chance whatsoever that the liquid from the second keg can make it in to the fermenting keg.
No, you don't need to keep your Ferment keg connected to the gas, I only ever connect the gas to the ferment keg at the very beginning of the system to ensure it's sealed, get it down to 6ish psi and then put a little less in the second keg and hook them up together, you should hear a couple of bubbles as the kegs equalize in pressure, and that's it.
I'm guessing that you got the backflow because when you shook your ferment keg, it was right at the start, so the ferment hadn't started yet and a couple psi worth of co2 was absorbed by the unfermented wort, leaving the pressure i that keg a tiny bit below the second keg, so that as soon as you reconnected, the gas equalized again and brought the starsan back.  Won't happen again as soon as your ferment starts the pressure in the ferment keg will increase every time you disconnect and shake.  Then when you re-connect, it will equalize and you'll hear a rush of gas going through the liquid in the second keg.
You had some check valves already for your draft system IIRC, would you like me to drop one off for you for the transfer line.  I'll probably be going by RB's today to get some stuff, so I could drop it off.

JQ

[Chris Craig]

I'm going to have to get a demonstration of this some time.  What's the major benefit?

[Jake]

yea John you're exactly right. I shook it up about 20 mins after it started, and obviously there was no fermentation present at this point ... so the key is to A) let fermentation start before shaking the full keg, and B) buy some check valves lol

It's been about 12 hours to this point and I still don't hear any fermentation. But once I do hear fermentation, you think I'm good to shake it up?

Right now neither keg is pressureized (other than from whatever fermentation may, or may not have, taken place so far).

[Ian Grant]

I've never spunded yet but Jake if you vented your empty keg before hooking it back up it wouldn't transfer back.

[Jake]

yea I realize that but from what I understand they're both supposed to be pressurized. I ended up venting both and I'm just gona let them both carbonate over the next couple days. I'm back in town Friday and it should be ready to drink.

Something else I did also, I cut an inch and a half off of the spunding keg's straw, so for when I do the transfer it will approximately take off the top of the yeast cake. Anyone else bother doing this? I figure it will transfer cleaner

[JohnQ]

Cutting the dip tube is something everyone does...once.
I did it, and now I don't know where that short tube is in my system.
I found that with a cold crash prior to transfer, you still only get a cup of trub up, and then with a slow transfer it comes up clean.

JQ