Know the basics. 1.25-1.5 quarts per pound of grain when mashing. Heat water 10-15 degrees warmer than desired mash temp. My question is when I sparge do I use the same amount of water as when I mashed? Also do I need to sparge for an hour like when I mash or will a shorter time work.
I also kno when mashing you lose roughly a half gallon of water to absorption. Does this happen with the sparge as well? Should I top off in my boil kettle?
oh, a multi-part question. . .
Q: When i sparge do i use the same amount of water as when I mashed?
A: Not necessarily. Sparge with enough water to hit your pre-boil volume. For me I aim for 6 gallons at the end of the boil so I can have 5.5 into the carboy and 5 into the keg. To do this I need to have 7.25 gallons pre-boil for a 60 min boil. So if I get 3 gallons out of my mash then I need to sparge with 4.25 gallons (doesn't matter which way you sparge, this math is true).
Q: Do I need to sparge for an hour?
A: The fly sparging section of this answer has been covered well enough. My regimen when I batch sparge goes like this: Drain the mash, Fill with half of my sparge volume, stir well, let sit 10 min, vorlauf, drain slowly (I find this helps to avoid grain bed channeling thus preventing poor efficiency), repeat.
Q: Does losing half a gallon happen with sparge as well?
A: Short answer, no. Long answer, I'm not exactly sure what you mean so I'll give both possible answers. There is dead space with every MLT I've ever come across, experience and measuring can help you determine that. You won't lose that dead space twice since it will have wort in it when you add your sparge water. Grain absorption is roughly one half gallon PER POUND of grain in your grist. Since your grain has already absorbed water during the mash you can safely assume it won't absorb a significant amount more.
Q: Should I top off my boil kettle?
A: No, I kind of cover this one early. If your short of your pre-boil volume it'll be okay to sparge a third time if your batch sparging. If your fly sparging, just sparge until you get to your desired pre-boil volume.