Here is a qute from Mitch...."A note here about batch sparging, which is the technique of drawing the wort off until you pull the grain bed dry, then adding sparge water until you are over the level of the grain bed, and repeating the process until you are at kettle full. Yes, you will increase your extract recovery using this method, and it is easier than trying to maintain a liquid level over the grain bed while filling your kettle. But you are also oxidizing your grain bed by exposing it to air, which can reduce the freshness of your final beer. Also, when you pull until the grain bed is dry, you compact the bed, and adding more sparge water on top can cause stuck run-offs, though that problem is rare. I still don’t recommend batch sparging. "