I’ve spunded my NEIPA and I’m going to cold crash at 30F. I should have15psi in the headspace, which is what I set my Spunding valve to. I plan on simply removing the valve and crash for 3-4 days. I think I’m fine so far.
The question is re kegging: I store my kegs fully purged and under pressure. I’m thinking I should have the Spunding valve on the receiving keg set to a couple psi lower than the transfer pressure, which should be what? Ordinarily I transfer at about 5-6psi and then force carb. I’m thinking the transfer pressure needs to be closer to serving pressure to minimize foaming, which is about 12 psi on my kegerator.
The pressure will likely drop on the keg that’s cooling, so it will likely be @ 8-10 psi after cooling unless you applied pressure during the crash cooling.
I transfer fully carbonated beer from the fermenter to a purged keg. I keep the pressure on the fermenter and use a spunding valve on the receiving keg (gas port). I basically push the beer from the fermenter to the receiving keg, the spunding valve is vented through a beer bottle filled with water. You don’t need the water filled beer bottle, but it helps to gauge the rate of transfer. The pressure difference between the two vessels is about 2-3 psi and the beer is transferred slowly. The pressure in the receiving keg and the slow transfer reduces foaming and maintains the carbonation.
I make sure the receiving keg is sanitize. I purge the receiving keg after a wash with Starsan by filling it with tap water dosed with SMB. The SMB will maintain the sanitation and acts as an antioxidant. By filling the keg and then pushing it out with co2, you will get the keg as close as possible (for a home brew setup) to zero oxygen and it uses less co2 compare to just purging the keg without the use of water. Any left over water will have a PMB in it to scavenge any oxygen present in the purge water.
Thanks! I’ll be cold-crashing in my Fermzilla that has the 15psi head pressure - I don’t expect that to go negative at my cold crash temp of 30F - to your point, likely 8-10psi. 2-3 days after cold crashing, I’ll keg, and you confirmed my thoughts on how to do it. I put the empty keg on a scale to measure the rate of transfer and final volume.
As for sanitizing, I fill them with StarSan and push CO2 through dispensing the StarSan in the next keg to be sanitized. The empty, sanitized kegs are stored with 30psi in them.