Originally Posted by pujiman
Thanks for the advice, it was like mentos and soda. Definitely don't want that to happen again
It's one of the reasons that a bucket can be a better primary container, as you have a larger surface area to handle any foaming.
With a carboy, it's often better to make the target volume and then remove enough to bring the level down just below the shoulders, the removed must being kept in a bottle in the fridge until all the nutrients are added and the ferment has passed the 1/3rd break.
With the foaming thing, it's best to stir gently to start with, so if the foam looks like it's heading north rather rapidly, you can stop and let it settle, then start gently again, etc etc, then once the foaming has subsided, keep stirring until the only foaming is from the movement of the stirrer/paddle/spoon.
Only then add the nutrients. Even then, if you're concerned that you might not have encouraged the dissolved CO2 to come out of solution, you can dissolve the nutrients in some must before pouring in.
With a batch that goes stinky, you do need to stir like hell, to encourage the dissolved CO2 to come out as it also seems to take any H2S with it too. Once the foaming is gone, you can even use an air stone and either pumped air or even compressed O2 if you have access to it, along with the nutrients. Stink is usually gone in about 24 hours, but if it comes back (and it can) then the same treatment is usually needed.
I can't say for certain, I've only had one batch go stinky, but I understand that it's a problem of earlier stages of fermentation, and doesn't seem to happen later on in the process so much (it might do, but I don't recall reading of batches going stinky later on).....