Partial Mash Sparge: Best Efficiency?

[MrEggSandwich]

I've done a few PMs, and have used both the "dunk" and the "pour sparge water over bag" methods of sparging.

What give me best efficiency/extraction?

I am planning on mashing 7.5LBs of grain in 11.25qts/2.8 gallons water

Sparge with roughly same amount (3 gallons).

Am I better off dunking? or pouring?

 

[IslandLizard]

Dunking rinses the grains better than pouring water over them.

When steeping, and when I did PM, I sparge twice with equal amounts.

Btw, that's a pretty large PM. What's your batch size?

 

[Rev2010]

If I were doing partial mashes I'd put the bag into the sparge water and open up the bag and stir the grains with a spoon. Nothing like stirring up the grains to really rinse off the sugars. When you're washing your hands do you move them around and rub them together or just hold them under water? I only do full mashes but I also double batch sparge. <- disclaimer though... many say it's completely unnecessary and a single is fine, but I'm happy doing so.


Rev.

 

[doug293cz]

Batch (dunk) sparging is easier to control and get consistent results than fly (pour over) sparging because you don't have to worry about fluid channeling, or other dynamic effects.

When batch sparging it is easy to prove (analysis here) that more sparge steps yield better efficiency, but after two sparge steps, diminishing returns set in rapidly. It is up to you to decide whether or not a second sparge step is worthwhile for your process.

In order to maximize efficiency with batch sparge (regardless of the number of sparge steps) it is important to minimize the amount of wort left in the grains/vessel before and after each sparge step. If you understand the analysis presented in the link, you will know why this is true. If mashing in a bag, you can minimize residual wort by squeezing the bag or letting it drain longer. Which is better depends on how aggressive the squeeze or how long you let gravity work on the drain. Long drain times are not conducive to multiple sparge steps. You also want to equalize the sugar concentration in the wort formed by the sparge water and the wort held in the grain after run off. This is the reason for aggressively stirring in the sparge water.

Choose a process that you are comfortable with and aim for consistency. That's the path to better hitting your projected OG's.

Brew on

 

[unionrdr]

^ This. I prefer the dunk sparge with boab brewing. Especially since I switched to a nylon bag, so I can dunk it, pull the top of the bag over the lip of the kettle to stir & let it sit 10 minutes. Stir once more & drain well. My OG's went up as a result.