Mash parameters effecting attenuation

[Big Monk]

[Bilsch]

Maybe the difference here is what speed I run the mill at that's causing a greater percentage of fines?
According to the drills literature, that would be about 400 rpm. Anyone else running that fast?

[Bryan R]

I run at 178rpm Russ. 65-75% depending on base malts.

[Owenbräu]

I found with malt conditioning that I could run the pump faster during heating, which allowed me to eliminate stratification.

I tend to crush coarse as well. I found a paper (I'll try to find it) that showed more fines require higher temps for complete gelatinization, so I'm not surprised you weren't getting good flow until you were you got up to higher temps.

[Bilsch]

That is quite a bit slower so maybe I'm just shredding the grain. The odd thing though is the crush looks good with the right size cracked pieces and decent hull integrity. Although there is a suspicious visable qty of fines and how the two happen at the same time is odd but must be a function of speed. Being a former BIAB'er made me quite lazy in worrying about the crush. I need to figure out a better way to drive mill slower as the cordless drill I'm using doesn't have enough torque to go slow. Constantly buying new stuff for the brewery is fun.. right?
Thanks everyone for the feedback.

[pinto]

I use this cheap harborfreight drill to run my grain mill.
http://m.harborfreight.com/1-2-half-inc ... 93632.html

I didn't want to burn out my cordless drill crushing grain. The battery alone costs more than this drill and it works great

Sent from my XT1585 using Tapatalk

[Ski]

I have a simple 2-roller Bulldog mill (both rollers rotating), set for 0.040" gap. But I mash thinly at around 4 - 5L/kg (1.9 - 2.4 qt/lb). I routinely get >90% conversion and lauter efficiency. I'm circulating with a small Topsflo 12Vdc pump (11L/min, 2.9 US gal/min), with a valve on the output throttled back to avoid cavitation on the inlet side, and to keep things calm. I kinda like this little pump because I can also use the variable DC supply to tone it down, instead of just relying on the valve. I think a nice steady continuous circulation is a good idea, exposing progressively more of the grain solids to the wort enzymes. Finally, I do a short quick sparge, mainly to displace the wort trapped in the grain. I also condition the grain (which I love doing) and I think this makes for a lovely fluffy grain bed. I've just switched to underletting too, and I think it makes much more sense than dumping a load of water onto the grain from a height. (We have no shortage of water being dumped on us from on high, here in Ireland!)
I'm kinda reluctant to go for a tighter crush. I think the thin mash does the job very well if you have good circulation (just not like the Niagara Falls). I've no idea whether a thick/thin mash makes a difference to the final product. Kai doesn't seem to think so. Perhaps it's fine in terms of efficiency, but I do wonder if it affects flavour.

[Bilsch]

As suggested by Pinto, I purchased a 1/2" slow speed drill from harbor freight and now am able to run my MM3 considerable slower then the roughly 400 rpm I was using previously. While I have no way to measure exactly, it's probably in the neighborhood of 100-150 rpm. The crush looks vastly different now with much less fine material. Even without conditioning the husks are far more intact compared to the higher rpm grind with conditioning.
edit: and then right after the first use it died... such high quality tools.

[Smellyglove]

[caedus]

I start my pump immediately after dough in mostly to double check temperature. I have a probe midway down the mash tun and one inline right after the pump, so I double check these to ensure that everything is going smoothly. I will usually recirc quite slowly and disturb the mash bed 1-2 times in the first 10 minutes to ensure no dough balls have formed. I get beautifully clear wort everytime. Probably could be clearer, but I can read text through it and I get very little muck in the boil foam.