Drain speed when batch sparging

[cladinshadows]

I hope this question hasn't been asked and I wasn't able to find the thread, but here goes...

Had a tougher brewday than normal on Wednesday (love/hate furloughs), my lauter kept misbehaving and I ended up just letting it trickle out for 30 minutes. It cleared and was draining steadily, just REALLY slowly. The sparge went fine and I was able to just let it rip like usual.

Now, I know that you're supposed to be able to not worry about drain speed when batch sparging, but I got 81% efficiency on this batch. I normally get 67%. I've never hit efficiency this high. 67% never bothered me, because I hit it like clockwork, but now what??

A few notes:
The only other difference between this batch and a typical batch for me is that I followed a recommendation that Jamil provides in BCS to grind the roast barley nearly to powder (I was brewing a dry stout). I suspect this was responsible for the difficult lauter.

I do a decoction mash-out to raise the grain bed to 168ish, drain, and sparge with 175F water.

Does it help to drain slower?? Anybody else noticed this??

 

[sparkyaber]

I think it has a ton to do with the fine crush. I fly sparge, so it is slow go for me all the time.
Here is a thread that I started a while back that has to do with crush and efficiency:

https://www.homebrewtalk.com/f36/has-more-effect-efficiency-crush-sparge-143646/

 

[Bobby_M]

The only reason I can figure a slow drain boosts efficiency is if you were previously having conversion issues. A long drain leaves extra time before the boil.

 

[cladinshadows]

Only the roasted barley was crushed, and when I was trying to figure out if that really could have boosted my efficiency, I calculated that even with 100% conversion on the roast I wouldn't have hit the numbers that I did.

 

[cladinshadows]

A few other notes about how this was different than normal for me:

This was a two step mash. First step target was 120F, rested there for 20 minutes. Second was the saccharification rest at 150F for 60 min. Would the two step have done something for me? I normally preheat the MLT by overheating my strike water by a few degrees and letting it equilibrate in the MLT to my desired strike temp... could adding the grains to the water (instead of the other way around) shock the enzymes in some way? I am looking for any advice you guys can give me to figure this out!

Thanks!

 

[Schnitzengiggle]

A few other notes about how this was different than normal for me:

This was a two step mash. First step target was 120F, rested there for 20 minutes. Second was the saccharification rest at 150F for 60 min. Would the two step have done something for me? I normally preheat the MLT by overheating my strike water by a few degrees and letting it equilibrate in the MLT to my desired strike temp... could adding the grains to the water (instead of the other way around) shock the enzymes in some way? I am looking for any advice you guys can give me to figure this out!

Thanks!

81% is darn good, and if I were in your shoes, I'd try to duplicate your procedure with a different recipe and see what sort of efficiency you get. I think Bobby_M has a reasonable explanation about additional conversion time due to your slow run-off. A step of 120° for 20 minutes promotes the proteolytic enzymes (protease and peptidase) which will help to produce FAN and helps to break apart the larger haze producing protiens, however, I would think this probably ramped up you enzymes to produce a more efficient mash.

Trying a different recipe that will not have any fine ground grain that will produce a quicker run-off yet still using your 120° degree rest will give you an answer to whether or not the additonal mash time is helping to give a complete conversion.

 

[mummasan]

About a year ago I had a tough time lautering and had a really slow runoff. I found that my eff increased on that batch too. Ever since I've been careful to runoff slowly and my eff has been great. I have never done a two step mash. I usually mash thin (2qts/lb) and then do a single sparge.

I used to get crappy eff but lautering slowly and doing a thin mash really helped.

 

[Denny]

Does it help to drain slower?? Anybody else noticed this??

I have tested this dozens of times and I've never found drain speed to have any impact on efficiency. If it does, then you're not getting all the sugars stirred into suspension before you drain.

 

[david_42]

Just time on grain. You could have probably gotten the same boost just by letting the sparge water sit there for 30 minutes. I do two sparges. I start heating the wort after the first runnings and don't drain a sparge until the wort is close to boiling. I know my efficiency is over 75%, because I use that to calculate and I consistently beat the OG.

 

[GoldMiner]

Put me down in the "full speed ahead" sparge group.

I do give the grain bed 10 minutes to settle before opening up the drain.

 

[Denny]

Put me down in the "full speed ahead" sparge group.

I do give the grain bed 10 minutes to settle before opening up the drain.

I don't find that necessary. In my case, the grain bed settles during the vorlauf.

 

[cladinshadows]

I'll update further after conducting more research. Be prepared for disappointingly inconclusive results!

 

[Kauai_Kahuna]

I'll update further after conducting more research. Be prepared for disappointingly inconclusive results!

Now that has to go somewhere in the classic quotes section!
I also think the extended time helped, along with the step mash. I stir very well on my first batch sparge, and start the vorloff right away. The second batch sparge I give it a few minutes, stir again and then vorloff. I usually manage a SG of 1.013 for the final sparge.
Not taking sides on the ever going debate, but I have found that dropping the crush to .38mm from the "standard" .45mm improved my EFF from around 72% to 82% or so.
At least my LHBS owner has no problem with adjusting his mill for me. I have a lot of work to do to convince him and all the "steepers" that a finer mash is a good thing and not bad.