Corny - transfer options

[Cider Wraith]

Continuing to delve into the possibilities of keg fermenting and non-air transfers and for anyone that has an interest would welcome comments -

Several weeks ago did several gallon cider batch in a carboy and an open air gravity transfer from carboy to corny. That corny immediately had air purged with a tank and went into refrigeration with a tank that carbonated and served it to standard practice ... it was great and just now kicked. But backing up - at that time, upon initially transferring the cider out of the carboy, I immediately added more juice to begin a new identical batch, and that carboy-based batch is now fermented and ready to go.

So what’s crossing my mind is, because I already have a cold C02 filled corny, and because I’m making an identical batch, to not even open that corny and just refill it with the carboy’s new contents. So how?

First, looks like one possibility would be an open-air gravity transfer from the carboy to another sanitized corny, and then connect that corny’s dip tube to the dip tube of the already C02 filled, cold corny, and use a tank to force the contents the transfer corny to the serving corny for it to again be a serving corny without ever opening it. I don’t have a spunding valve (I understand I’ll have to buy or build one) because I’m aware I’ll have to be releasing pressure in the receiving corny to allow the transfer to take place. But then again, in that case I guess I’m still sacrificing a corny of C02 to do the transfer, so how about, could I use a tank to start a siphon and then vent the receiving corny to allow the transfer to take place

Yes, I appreciate that one couldn’t do transfers like this indefinitely without stopping to clean, but maybe a time or two? And, open-air transfers out of carboys will be a thing of the past after this last carboy-based batch is transferred

UPDATE - because I already wrote all that I won't delete it but how about this… Connect the end of the auto-siphon tube to the dip tube of the C02 filled corny and start a syphon from the carboy. Then, quickly the syphon would stall because the corny was pressurizing, but then just continue venting pressure in the corny until the gravity transfer was complete. I wouldn't be preserving the pressure in the receiving/serving corny but I also wouldn't be allowing air in. In that case would that be a “semi non-air” transfer?

Well, being a noob at corny to corny transfers maybe there’s some big possibility I’m missing.

Suggestions/musings welcomed - thanks

 

[Whisky River]

I would think you could do a closed loop pressure transfer from your carboy to your corny keg. You should only need 2-3 psi to keep the transfer siphon going so if your carboy is glass you would have to decide if you think that’s a safe number but I would be comfortable doing it. Then just release most of the pressure from the keg, connect some low pressure lines and let the transfer run. Should take about 20-30 minutes but you should be able to avoid any additional oxygen exposure.

 

[Cider Wraith]

Appreciate the reply... well, I'm working on the kitchen countertop and cracking a carboy would spell nuclear meltdown... I am vaguely aware that there are accessories that allow slight pressurization of carboys but I'm expecting to be phasing them out so not worth it for a single use

Since my original post I'm still thinking of a gravity transfer

Seems like the existing serving keg, empty of liquid but sitting at 8 PSI of C02, is going to have to be brought down to ambient pressure... well, let's say that if not then the tank pressure/volume required to transfer into it would be defeating the purpose. So in the process of bringing it down is there anything useful or novel that pressure could be used for? So let's say the receiving corny is at ambient pressure, maybe then open the purge vent and rotate 90 deg to lock it open. Next, use a hose clamp to connect the end of an auto-siphon hose to a barbed black liquid ball lock, then attach to the dip tube side. Finally just start a siphon and give it half an hour or whatever. So in that case that's not a truly closed transfer but close and wouldn't the vast majority of equalized pressure C02 just mostly stay in the corny, that is what isn't naturally displaced?

There is a post I'll go read regarding the uses of escaping C02 from a fermenting corny. Seems like in a way, for two to three days fermention in a corny creates a sort of free C02 gas pump