Primary in Corny Keg - pressure question

[McKnuckle]

I'm fermenting a 2.5 gallon batch in a 5 gallon corny for the first time. It's US-05 at 68F, which I have done many times in a carboy. I have a blow-off hose connected to the keg's gas input port. When fermentation has finished, I want to transfer the beer off the trub to a 2.5 gallon serving keg.

My question is this: I would prefer to passively siphon the beer, rather than use my CO2 tank to force it out. I am aware that I need to vent pressure (which I'm doing) during active fermentation. But is there a point where I can remove the venting apparatus, allow a small amount of pressure to build up, just enough to start liquid flow and allow gravity to finish the siphon?

Perhaps I can remove the venting hose after, say, 7 days, then perform the transfer on day 10 - or something like that? I'm not measuring PSI in any way, but maybe someone has done that and can offer their experience on when my desired next step might be feasible.

Thanks

 

[Weezy]

Without a pressure gauge, it's a bit hit or miss. But when I ferment in cornies, I just leave the poppet locked open and cover the top of the keg with a plastic grocery bag. After the first three days, I'll seal it up and use a pressure gauge to keep the pressure at 5 psi. 5 psi gets it partially carbed and plenty of pressure to force transfer without added tank co2. You really should try to do something like this. Forced transfer is one of the biggest benefits of fermenting in kegs (as is protection from oxygen).

I use one of these:
https://www.williamsbrewing.com/0-60-ADJUSTABLE-PRESSURE-RELIEF-VALVE-P3453.aspx

I'd like to find a replacement for the pressure relief valve part that is hard set at 5 psi. (It's just one of those things that I haven't gotten around to sourcing)

 

[thekraken]

I don't have personal experience with this procedure yet but it seems to me that if you don't have a pressure gauge set up you're just playing a guessing game. Here is a recent thread that does very close to what you're asking with the xfer:
https://www.homebrewtalk.com/showthread.php?t=600563
Also, another good read:
https://www.homebrewtalk.com/showthread.php?t=44344