poor efficiency when moving to keggle

[zeprock2]

So i have been brewing all grain for about a year and have been using a 10 gal cooler to mash with bazooka screen. I want to make bigger batches so I converted a keg with a false bottom. Since I moved to the keggle my efficiency has been way off. With the cooler I was getting around 75% eff. Now with the keggle I am getting 65% eff or lower. My temperature seems to be consistent during mashing, my grain crush is good, so I dont know what changed. The only thing I can think of is that there is that gap under the false bottom and that is messing with my numbers. Has anyone else ran into this? Is there a way to account for this? My thinking is that when I put my strike water in the keggle some hot water is under the false bottom and the grain never touches it. So when I sparge later, my wort is getting watered down..

 

[processhead]

A couple of things to check.

Do you use a dip tube with an opening that is within a 1/2 or less from the bottom of the keggle? This will prevent you from leaving any wort behind in the dead space under the false bottom during the run-off.

If you are fly-sparging, make sure you use a sparge device that circulates sparge water evenly over the top of the grain bed so you don't experience channeling through the grain bed.

Are you monitoring the temperature of your sparge water over and in the grain bed?
At a minimum, make sure it stays in the 168-170 degree range so that you are adequately dissolving all the sugars in the mash.

Do you maintain the run-off until the SG hits 1.010 or the pH increases? Or just till you are out of sparge water?

Make sure you continue the run-off until your SG or pH indicates that you have dissolved all the sweet-goody out of your grain bed, or else you may be leaving gravity points behind in the grist.

As you mentioned about the water in the free space under the false bottom, if you are hitting your mash-in temperatures, that should not be a factor. Nor should it "dilute" your run-off after the first few minutes of the run-off.

 

[zeprock2]

I have to measure but since the bottom of the keg is concave I think the dip tube is more like 1 in to 1 1/2 in from the bottom. i'll double check.

I do fly sparge and I am usually pretty good about pouring the sparge water evenly over grain bed and keeping a couple of inches of water on top of grain.

I am monitoring the sparge water temp and i keep it in a color to maintain temp. Like you said I keep in in the 170 range.

When I get my run off I just sparge slowly until I get my boil volume. I never looked at the SG. Maybe I should play closer attention to that.




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[processhead]

The next time you brew, take an SG of the runnings towards the end of the run-off when you are close to reaching your boil volume.

If your run-off is still above 1.010, keep sparging. You can always boil a little longer to reduce the volume to the correct end-boil volume.

This will allow you to get more extract from the grain and should improve your efficency.