I dunno, if you saved time by fly sparging, you were doing the batch sparging wrong...at least this was my experience.
Of course, I may be the one doing the fly sparge wrong...I'm under the impression that a fly sparge for a 5 gallon batch (7 gallon pre-boil)should take about an hour of sparging.
A double batch sparge would take maybe 20-25 minutes.
Yep. I fly sparge on my system, usually, but the last few times I"ve been batch sparging. I'll give up 3% efficiency to save 45 minutes.
When you batch sparge, you drain the MLT completely. Add 2 gallons of 190 degree water (to bring the grainbed up to 168), stir it well, open up the ballvalve, and drain to a pitcher. Within a quart, simply turn the end of the hose into the boilkettle and pour the contents of the pitcher over the grain bed. When it runs dry, close the ballvalve and add the rest of the sparge water to the grain bed. Stir like a maniac, open the ballvalve and start draining into the pitcher. Turn the hose into the BK, pour the contents from the pitcher onto the grainbed, and drain the MLT. That takes 15 minutes, max.
Another thing that I like in batch sparging is you can start the first runnings onto boil right away, negating the need for a mash out. So, by the time you've drained the second round of batch sparge runnings, the BK is already near a boil. That also saves time.
For fly sparging, you will add your mash out addition. Then make sure there is at least an inch or more of liquid over the mash, then vorlauf (same as in batch sparging), then drain over the course of 45 minutes to an hour while the HLT slowly keeps the water level the same. After an hour, it should be done. Then you can start the boil.
The fly sparging takes longer, but I will sit and enjoy surfing the internet or have some lunch during the sparge. It probably takes an hour longer total in my brewday.
