Mash parameters effecting attenuation

Wort making

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Big Monk
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Re: Mash parameters effecting attenuation

Postby Big Monk » Tue Jun 28, 2016 10:06 pm

Bryan R wrote:I use a captain crush 3 roller, and I am as tight as the eccentric rollers allow me to go....020 or less. Another tidbit is to only restrict the output of the pump, so leave all valves all the way open, and only throttle in on the out side of the pump( say on the wort return entrance). These mag drive pumps hate their in side throttled.

Cheers!


In general, what kind of efficiency are you getting with the no-sparge mashing?
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Bilsch
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Re: Mash parameters effecting attenuation

Postby Bilsch » Tue Jun 28, 2016 10:26 pm

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
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Re: Mash parameters effecting attenuation

Postby Bryan R » Tue Jun 28, 2016 10:36 pm

I run at 178rpm Russ. 65-75% depending on base malts.
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Ancient Abbey
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Re: Mash parameters effecting attenuation

Postby Ancient Abbey » Tue Jun 28, 2016 10:56 pm

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.
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Bilsch
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Re: Mash parameters effecting attenuation

Postby Bilsch » Tue Jun 28, 2016 11:16 pm

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
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Re: Mash parameters effecting attenuation

Postby pinto » Tue Jun 28, 2016 11:50 pm

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

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Ski
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Re: Mash parameters effecting attenuation

Postby Ski » Wed Jun 29, 2016 3:33 pm

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.
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Bilsch
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Re: Mash parameters effecting attenuation

Postby Bilsch » Wed Jul 06, 2016 6:45 pm

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
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Re: Mash parameters effecting attenuation

Postby Smellyglove » Sat Feb 25, 2017 7:26 am

Bilsch wrote:I believe my attenuation issue is finally resolved and all evidence points to the crush being the culprit. The first clue was not being able to get close to the 1°c a minute temperature ramp profile without over heating the lower part of the mash. Obviously circulation was an issue, especially during in the first 20 minutes or so of the mash. Too little flow through the grain bed was hampering heat exchange from the bottom where it’s heated then through the pump back into the top of the mash.

To check what was happening I removed the mash cap and gently probed with a long spoon only to find the grain bed very stiff and compressed onto the false bottom by the suction of the pump. My system is equipped with a ball valve restricting flow that is never more than about 50% open. So it seemed most probable insufficient flow through the grain bed had to be the problem vs too great a volume delivered from the pump. More than likely the situation was aggravated by the fines of the over crush further clogging the column blocking free liquid passage. The improving flow over time was perhaps attributable to the finer material gelatinizing, converting and going into solution thus opening up more flow channels through the column. Because the excess powdery starch limited the flow early on, that then reduced the contact time, surface area and thus efficiency of the maltose rest. Later the improving flow combined with the increasing temperatures of the mash profile gave alpha amylase a better shot and doing more of the conversion resulting in poorer attenuation.

Maintaining a closed system as much as possible from oxygen made finding this problem more difficult with not wanting to ever remove the mash cap and go mucking around in the grain. Poor crush seems like a pretty rookie mistake but since my mill is set to a conservative .036” gap it really didn’t stand out initially as a suspect since historically finer grist results in better attenuation. Anyway I have since increased the gap to .048” and that seemed to solve the problem with surprisingly little or no loss of efficiency in the latest batch.

I’m using the MM3 and would love to hear what others are using as their mill gaps.


Hi. My first post. I just recently found this forum and must say that I'm eager to start reading what's on here.
You thread was interesting because I experienced the same after moving from a three vessel HERMS setup to a two vessel no sparge HERMS setup. I turned down my boil and skipped holding a 72C-step, (just stepping through it @ 1c/min now) and rather took a hit on efficiency.

Anyhow, just a quick, and maybe a stupid question. When do you start your pump? If it's directly after dough in you will most likely get a too compact grain bed.
caedus
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Re: Mash parameters effecting attenuation

Postby caedus » Sat Feb 25, 2017 12:58 pm

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.

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