If you trying to avoid oxygen, pressure fermentation can help, but you should consider the effects on the yeast. The pressure doesn’t effect the yeast directly, rather it increases dissolved co2. The co2 causes the yeast to behave differently and it has a tendency to reduce ester and high alcohol products. The yeast also grows at a slower rate. Not really the best type of environment for ales, ester products add to the flavor and character of the beer. The second thing to consider is dry hopping with a beer that’s carbonated, causing the dreaded hop volcano.
All you really need to do is to keep the fermenter completely closed and avoid any oxygen from fermenter to the glass. Easier said then done. You could ferment at lower pressure. I ferment lagers at 4-5psi at 48F. The esters are eliminated. If you keep the pressure at 2psi or so, you could keep the temperature at room temperature, keeping esters and avoid carbonating the beer before dry hopping.
The biggest risk to oxygen ingress is when you open the fermenter to dry hop or add clarifiers. The second is kegging. The first on can be accomplished by keeping a positive pressure on the fermenter by adding co2 when it’s open. This requires a way to inject and vent co2 at the same time. This is similar to what pro’s do and keeps a very slight positive in the fermenter The kegging problem is solved by closed transfers. All beers, not just NEIPA’s, benefit from these techniques.
