'Pulse' Sparging

Chris Alvey · Post by **Chris Alvey** » Tue Feb 19, 2008 6:03 pm

The most recent BYO magazine had an article comparing Batch to Fly sparging. One thing they mentioned was the oxidation potential from exposing the mashed grain to air between the drain of your mash liquor and the addition of the sparge water batch(es.)

I thought when I read the article about a 'hybrid' batch-ish sparge method that could eleminate this oxidation potential (however arguably small) and increase extraction percentage a bit.

I just read and article on the brewboard where a guy did this and seems to have some positive results including increased efficiency and a 15min time savings : http://www.brewboard.com/index.php?showtopic=87497&st=0

Did anyone read this article in BYO and have the same thoughts? I think I am going to give this modified batch sparge (i.e. the 'pulse' sparge - unless they come up with another name) a go next time I brew.

I realize that, in the larger picture, it is probably a very little thing that will affect the final product minimally, but I really enjoy worrying about (and researching) my mashing process, so for me, it's part of the fun.

Talk amongst yourselves...

john mills · Post by **john mills** » Wed Feb 20, 2008 8:33 am

This seems similar to the method I've been basically doing "a lazy fly sparge" I add about a gallon of water at a time for each addition of water while sparging when the level drops to just above the grains (if I'm paying attention) or till the grains have been exposed just a little on the top. I adjust the out valve until about 1 qt/min max is coming out ( it us usually closer to 3/4 qt) so it gives me about 5 minutes between additions of water. Using this method, and allowing about 5 minutes between water additions I use straight boiling water. My grain bed temp maintains close to mash out at 170 degrees. According to promash my last batch of American Wheat hit 88% given my grain bill, batch size and SG.

Reading further in the brew board post they're talking about flow dynamics and how sparging technique over sparges the grain in the middle and leaves the perimeter loaded with sugars. I don't doubt their studies, but my method of placing a wide rimmed soup bowl on top of the grain bed to distribute the pressures of the addition water, covers about 1/2 of the radius of my keggle. I think this helps force the water to the perimeter then flows toward the center where my homemade bazooka screen is sitting on the bottom.

Chris Alvey · Post by **Chris Alvey** » Thu Feb 21, 2008 10:21 am

Yea, mash tun design is kind of the other side of the coin that I thought about after I posted this. I have a single bazooka screen in the middle that would be about the least optimum setup for any sort of fly sparge.*

I re-thought my approach to this and I am now not sure whether the increase in efficiency from this 'pulse' sparge in a very inefficient lautering setup like I have would be better than just dumping all of the sparge water in and stirring the sugars back into suspension like I had been doing.

I think the ideal thing would be for me to improve my setup to either a false bottom or circular-ring type setup before this technique would show any real benefit.

*How To Brew, Palmer : (http://www.howtobrew.com/appendices/appendixD-2.html)

john mills · Post by **john mills** » Thu Feb 21, 2008 11:55 am

The setup I use (which is about as simple as it goes) is a single pick up from a rolled screen at the bottom of a converted keg. I wonderd one brew day if I was leaving any sugars behind after I was finished with my fly sparging.
I drained all the runoff from the grains as usual, and took a gravity reading from the last bit 1.007. I then added about a gallon of boiling water back into the grain bed and stirred until it was well incorporated, let it set for a few minutes, then vorlaf until clear, and tested the runnings again. Result was the same gravity as measured before: 1.007.
Yes there is some sugars left, but nothing worth the wasted *propain* to boil down into a fine beverage. If I needed to lower my SG of my brew I could have continued to use this liquor, but I had already reached the volume I needed.
Of course I didn't throw this away. I just put it in a smaller pot and boiled it down until a quart was left and had about a 1.030 yeast starter for next time. If I had a wood burner that I kept a pot of water on to add humidity to the room, I would just collect all the sparge I could after my initial volume was reached and have a lot of "free" starters available.

Chris Alvey · Post by **Chris Alvey** » Fri Feb 22, 2008 7:34 am

That's a very interesting and enlightening experiment.

I really want to do some experiments like those this year to settle some things in my mind and publish them on my website.

Wanna write an article about your experiment? I'd be glad to html it up and publish it if you want to.

john mills · Post by **john mills** » Fri Feb 22, 2008 8:55 am

I could do a write up, and take some pictures of the process and equipment, but I'd like to run a few more trials before jumping to any conclusions. The brew I did this trial on was also "fortified" with a half pound of rice hulls. The addition of the rice hulls is supposed to help prevent channeling, and stuck runoff. But it might be noted I have done the same recipe again without the rice hulls, and had an even greater rate of efficiency. I was just chalking up the increase of efficiency to a change in the mashing technique.
What a better excuse to do more brewing than to say "I'm doing this for science." Even if there is repeatability, it may only mean that my set up, or process, is consistent.