[chuckger]

I just installed a March 809 hot pump on my system and was excited to use it for circulating the mash before starting to drain into the boil kettle.  I ran the pump full open right off the bat and it worked great at clearing up the runnings, but the amont of wort being pumped back into the kettle quickly became less and less.  Then when I ran from mash to boil, it ran super slow with or without the pump, it almost seems to me that the pump sucked the grain into my false bottom and cause it to clog, any body had anything like this happen to them while using a pump?  This was my first stuck mash EVER!  and I didn't like it much. 

[denny]

I'd guess full open was the problem.  You probably compacted your grain bed.

[tom]

Definitely. I go 50% open at the most.

[hopfenundmalz]

Put a ball valve on the pump's output to control the flow.  Otherwise the vacuum you create will pull the grainbed down and cause it to stick when you are sparging.

When recirculating the mash for temperature steps with direct fire and the pump running on a higher flow, I give the mash a stir now and then to keep it suspended.

Experiece will show you what to do, and now I don't even think about it while brewing.

[chuckger]

I figured that was the problem, running full open I mean, I have not had a chance to brew again so I have not tried it again but next time I will definately run about 30% or so instead of 100% just wanted some one elses insight.  Thanks guys.

[a10t2]

I had the same problem. The biggest reason I've stuck with malt conditioning is that it lets me run the pump full open without a stuck sparge. Each runoff takes less than two minutes.

[bobby_m]

Start the recirculation really slow to set the bed without compacting, then run no more than 50% throttle. I also agree that conditioning your malt before the crush is a real help there... assuming you own a mill.

Bobby

[richardt]

... biggest reason I've stuck with malt conditioning is that it lets me run the pump full open without a stuck sparge. Each runoff takes less than two minutes.

Improved lauterability was the reason I gave malt conditioning a try.  Problem was that I tried to "eyeball" the wetness of the grains rather than do the math--ended up using 3 times the amount of water I should have and with rollers that looked like corndogs.  Not to mention a lot of unnecessary aggravation taking the BC apart, cleaning it, and putting it back together.  Don't overdo the hydration of the grains.  Stay on the drier side.

[wilypig]

I recently started using a Barley Crusher instead of my Corona mill and had just read the 2 articles in the BYO and Zymurgy on Malt conditioning. I just throw about 0.5 cup of hot water in my base grain and stir with my hand until well combined and rest for 5 to 10 minutes. After grinding I run my specialty malts and crystal through with out conditioning and that cleans the rollers very nicely.