I've seen on some tutorials where they leave CO2 valve open and just open the vent several times. To me that's more of a purge/sweep. To me I want almost total replacement. Close CO2 each time and depressure to almost nothing. Shouldn't take many times. That's how we do it at work on large...
We used citric where I worked before as a metal scavenger. Don't remember concentration. We mixed granules and water. You can get citric with canning supplies.
I got lazy about it but finally went all grain a few batches ago. Now I got the fever. Guess it's more rewarding. And I also have a toddler instead of a baby now.
How do you all go about cold crashing a batch when there may be another batch still fermenting? I've got a temp controlled freezer as my fermentor.
For now I can move it to my garage fridge to crash but I plan to make that my kegerator.
Thanks