Step Infusion question
In the most recent Zymurgy, there is a recipe that involves step infusion mash. It's not quite explained how to get the wort off the grain.
So I was wondering how a step infusion mash works? I currently brew BIAB, with my own sparge/rinse system, getting about 75-85% efficiency.
This step infusion calls for some water at 140 degrees (30 minutes), then some boiling water (again 30 minutes, mixing with previous water, the boiling temp is mitigated), then "lauter and sparge" with 3.5 gallons to get 6 gallons runoff. My question is what is 'lauter and sparge'? Aren't they the same thing? This is related to my question here, but this question is about a specific recipe and method. That question is more general.