A foamy beer is usually due to the fact that the minikeg is not cold enough. You want to wait until the light is green to start pouring. We recommend keeping the minikegs in the fridge until you tap them, so that your beer is always fresh and protected from temperature variations.
To pour the perfect beer, we recommend holding your glass at a 45° angle, and close to the nozzle of the SUB. Turn your glass back to a 90° angle just as your beer reaches the edge of your glass, and fill until the glass is full. It is okay for the beer to flow over just a bit, as this will ensure you get the perfect beer to foam ratio – just make sure your drip tray is underneath your glass!