Is this a compacted bed?

[CharlosCarlies]

My apologies for the possibly stupid/noob question, but only on batch 10 or so w/ our new brewhouse and still working out some minor kinks. This was our first higher gravity beer (17-18P), so was expecting some potential lautering problems. I calculated for slightly lower efficiency (85-87%) and we somehow hit that despite a pretty ugly looking grain bed post-lauter.

Our 12-13P beers have been super easy: ~92% efficiency, 70-80 min run-offs, etc while this beer took 2 1/2 hours and the efficiency wasn't great obv. FWIW, during the initial run-off the bed seemed like it was going to be nice and loose then fairly quickly tightened up resulting in a 2+ hour run-off. My first inexperienced thought was the bed compacted, but didn't notice any difference in clarity and we were already 30 min in so we just went with it.

Really appreciate any thoughts.

[BrewinLou]

Very hard to tell once it is drained. Something is not right at 2.5 hours. Do you run the rakes at all while running off? Can you raise and lower your rakes, as well as control the speed?

[CharlosCarlies]

Rakes are fixed height but we can control the speed. We basically just use them for mashing in/grain out.

FWIW, I could somewhat see the bed during the sparge and there were definite dark spots that line up w/ where the bed ended up, so my guess is it was that way for a good portion of the run-off.

[d_striker]

I would love 87% efficiency on a 17P beer. I would hardly consider it poor efficiency.

[BrewinLou]

Depending on how close your rakes are to the false bottom... We run our rakes as slow as they will go during the entire runoff. As long as you are at least 4-6 inches off the false bottom give it a shot, it should not break the bed. You should be able to eeek out a few more percent efficiency, it should def decrease that runoff time to a reasonable amount. Leaving them off during the runoff leaves a bigger possibility of channeling than having them turn. Finally how much sparge water are you using? I find with our system we finish sparging right around the same time we have the kettle half full.

[CharlosCarlies]

Wish we could run the rakes, but they're literally touching the false bottom and aren't adjustable. Really just designed for mashing in/grain out I would think.

Maybe we shouldn't be disappointed w/ 85% efficiency, but I just really didn't like the way the bed looked and haven't seen it before with our standard gravity beers.

[JDN]

If your runoff gets way too slow, you can stop lautering, run the rakes a couple revolutions to cut/loosen the bed, vorlauf until clear and then resume filling the kettle. This was standard practice on a 50bbl lauter tun without adjustable height rakes that I used to run. It definitely saves time.