headspace for 1 gal secondary pitch

[Brif]

About to pitch straight dregs (direct from 2 bottles) into one gallon.
Dregs are blend of brett and bugs.
Its a 4L jug, but right now it sits right at 1gal, so only about 8oz or so of headspace. Is this enough given that I'll be adding an ounce or so of dregs?
Is the Brett going to take off and blow through my s-lock? OR, am I good?
pic attached

Thanks!

 

[crane]

From my experience you should be fine. Dregs seem to take a while to get going fully, even when I have stepped them up prior to pitching into unfermented wort.

 

[Brif]

Thanks, I took a couple ounces out, since I added a couple ounces, and may add more

 

[jfolks]

If primary fermentation was completed prior to adding your dregs, there won't be any krausen (pellicle yes perhaps). If this is a primary fermentation, then you might need to blow off