Ok, a little background before I get into what Batch Sparging is.
The following is based on 5 gallon batches with 10-11 pounds of grain
being used.
Most all grain brewers us a technique called "Sparging". Sparging
is when you run hot water over the mash grains after the mashing is complete.
This is done by slowly trickling water that is 170 degrees over the grain
bed and at the same time slowly letting the wort flow into the kettle so
that it takes 45-60 minutes to fill the kettle to brewing capacity.
The purpose behind this is to get as much sugar out of the grain as possible
as the water slowly rinses though the grain. The problem with this
is you have to monitor the process very carefully since you do not want the
grain bed to dry out and cause a possible stuck sparge. Secondly, you
also have to make sure you don't over sparge and leach tannins into the wort.
This happens when the gravity drops below 1.008.
There is also something called "No Sparge". This is simply draining
the wort from the mash tun right into the kettle without sparging.
The result is the same gravity as you would end up if doing the standard
sparge. The main disadvantage is you waste a lot of extract since it
remains in the grains afterwards. The upside is that it is very quick
and you end up with very smooth and rich wort. This process also minimizes
the chance of any tannins leaching into the wort. Count on using about
25% more gain than the regular sparging method.
Then comes "Bath Sparging", this is sort of in between the other two.
One thing to keep in mind when doing this process is that you will get
better efficiency if the two runoffs are of equal volume. An example
is if you are doing a 5 gallon batch, the first runoff will be 2 1/2 gallons
and the second will be about the same. In this process you add about
2 gallons of 170 degree water to your mash tun after mashing is complete.
Then you stir up the mash and let rest for 15 minutes to settle out.
Then recirculate until the wort runs clear. Drain completely into
your kettle. Now add enough 170 degree water to the empty mash tun
so that when you run it off it will bring your level to 6 to 6 1/2 gallons
in your kettle. Stir again and let sit another 15 minutes. Then
recirculate until it runs clear and let then drain into the kettle again.
That’s it!!
When using this method you will need to add about 1 more pound of grain
to get the same gravity you would get if you did the regular sparge method.
The upside is it will cut about 30-60 minutes out of your brew day.
The only thing that is tricky with this method is knowing how much water
to add the second time you fill the mash tun. The best way to know
this is if you can mark you kettle off in gallon increments, that way you
will know how much to add exactly. You wont have to worry about how
much the grain will soak up since this has already taken place earlier.
You don't want to overestimate the volume since this will cause your gravity
to end up low. If you end up a little short you can add some make
up water to the kettle. I used this method just recently and
it worked great for me. The additional pound of grain was well worth
not having to set up the regular spaging system and the constant monitoring
of it. Give it a try and let me know how yours turns out.