Mash is Efficient, Not Rinsing All Sugars

[lslbrew]

I did a basic pale ale yesterday, batch sparged and still had lots of sugar left in the grains.

18.5 lbs 2 row
1.5 lbs 60L

Mashed with 6 gallons at 150.
Drained and got 3 1/2 gallons at 1.087. I use a brew bag to line my cooler and drain the mash tun.
Added 4 gallons at 170 for 15 minutes. Drained and had a total of 7 1/2 gallons at 1.062. I did a weighted average for running 1 and 2 and got that the 2nd running was 1.041.
Added 4 more gallons at 170 for 10 minutes. Drained for a total of 12 gallons. I let the last run much longer to let wort drain out of the grains. Pre boil gravity was 1.048. Did a weighted average and calculate the 3rd running was 1.025.
All gravity readings were adjusted for temp.

If the above is correct that tells me that there were still lots of sugars in the grain bed. Is there a way to get these sugars out without increasing the total pre boil volume? If I use less grain, will the increased water to grain ratio rinse more of the sugars out? Maybe a mash out then only run 2 instead of 3 would thin out the first running and get more sugar?

 

[doug293cz]

That's the way brewing works. It's not possible to get all of the sugars out of the spent grains without using huge amounts of water. Your lauter efficiency, about 89% was close to optimal for a double batch sparge. However, your conversion efficiency was only about 87%, which is not so good. A finer crush, longer mash and/or more stirring during the mash could help increase your conversion efficiency. Doing a single batch sparge will decrease your lauter efficiency, and using less grain will increase your lauter efficiency but result in a lower OG. Here's a chart that shows how lauter efficiency varies with grain weight to pre-boil volume ratio for different batch sparge counts.



Things you could do to increase your lauter efficiency:

1. Let all drainings run as long as your last draining. This would decrease your grain absorption rate from 0.125 gal/lb to 0.1 gal/lb
2. Do three batch sparges instead of two.

The first option would increase your lauter efficiency from 89% to 91 - 92%. The second (with sparges of 3 gal) would also increase your lauter efficiency to 91 - 92%. If you combine the two, your lauter efficiency would go to 93 - 94%. Not a huge gain for more work/time.

Brew on

 

[Bobby_M]

A few notes..
With a brew bag, you can attempt to squeeze more wort out during draining.
You didn't mention what kind of cooler, but it's hard to get a full drain when most of the bag is jammed right against smooth walls. Essentially it's mostly draining right at the spigot. Anything laid on the bottom of the cooler to create drain channels towards the spigot/drain would reduce apparent dead space.
How much actual dead space do you have? If you put 2 gallons of water in the cooler, how much doesn't drain out?

 

[doug293cz]

A few notes..
With a brew bag, you can attempt to squeeze more wort out during draining.
You didn't mention what kind of cooler, but it's hard to get a full drain when most of the bag is jammed right against smooth walls. Essentially it's mostly draining right at the spigot. Anything laid on the bottom of the cooler to create drain channels towards the spigot/drain would reduce apparent dead space.
How much actual dead space do you have? If you put 2 gallons of water in the cooler, how much doesn't drain out?

OP's effective grain absorption rate (includes actual grain absorption and MLT undrainable volume) works out to 0.125 gal/lb for first two drainings, and 0.10 gal/lb for the third draining. Since 0.125 is typical for a traditional MLT, the OP's undrainable volume must be close to 0. OP's long 3rd drain got into the absorption range of a typical no-squeeze suspended BIAB drain. Squeezing, particularly after the initial drain, would definitely improve lauter efficiency.

OP's biggest gain would be from increasing conversion efficiency from 87% to 95% or higher.

Brew on

 

[lslbrew]

You are correct, undrainable is near zero. I use a recangular cooler and prop the opposite end up, pull the bag back and everything but grain absorbed liquid will drain.
The mash was 60 minutes. I stir every 15 minutes and ran the grains thru the mill twice at the LHBS. This was the first time I double milled the grains. I was looking for an overall efficiency jump. It was up a few points but not much.
I may be at a point where the increase in work or time won't be worth the increase in efficiency.
Everything you read says not to go below 1.010 on the runnings so I was surprised that he last of my runnings were much higher than that. I guess I didn't know what to expect that it should be.

 

[RM-MN]

You are correct, undrainable is near zero. I use a recangular cooler and prop the opposite end up, pull the bag back and everything but grain absorbed liquid will drain.
The mash was 60 minutes. I stir every 15 minutes and ran the grains thru the mill twice at the LHBS. This was the first time I double milled the grains. I was looking for an overall efficiency jump. It was up a few points but not much.
I may be at a point where the increase in work or time won't be worth the increase in efficiency.
Everything you read says not to go below 1.010 on the runnings so I was surprised that he last of my runnings were much higher than that. I guess I didn't know what to expect that it should be.

If your LHBS has the mill gap set too wide, running the grains through a second time won't improve the crush much. If you are willing to put it a few dollars and some work cranking, a Corona mill of your own will let you choose the fineness of the milling. I've been cutting my mash time down to 20 to 30 minutes and find that to be plenty.

 

[lslbrew]

If your LHBS has the mill gap set too wide, running the grains through a second time won't improve the crush much. If you are willing to put it a few dollars and some work cranking, a Corona mill of your own will let you choose the fineness of the milling. I've been cutting my mash time down to 20 to 30 minutes and find that to be plenty.

Yeah, I was thinking about this last night while trying to go to sleep. The crush I had was about 3 pieces from each individual grain of barley. Seemed decent enough to me. But with a mill I could get even finer. Of course, if I did that then I would want to buy the base malt in bulk to "save money" but that would mean that I need a good air tight bin for my grain. Not sure I want to give the mouse a cookie...

 

[kh54s10]

For airtight bins you can go with 5 gallon buckets and Gamma lids. For smaller amounts I have several sizes of lock and lock containers.

I think, work on your grain crush, though your description of the crush you used is probably as good as you are going to get.

You will never get all the sugars out of the grain. The 1.010 number you quoted is usually where people stop a fly sparge.

I would work on all the other processes and just do a single, or in my case a double sparge. I only do a double sparge so that I get an accurate preboil volume without leaving a lot of wort in the mash tun. I measure the first runnings volume, sparge with about half of what is needed to get to preboil volume, measure again then add the rest.

I also find that adding sparge water then letting it sit doesn't accomplish much. Add the sparge, stir, vorlauf then drain. No need to lengthen brewday letting the sparge water sit. Ultimately you are just rinsing the grains.

 

[Hwk-I-St8]

That's the way brewing works. It's not possible to get all of the sugars out of the spent grains without using huge amounts of water. Your lauter efficiency, about 89% was close to optimal for a double batch sparge. However, your conversion efficiency was only about 87%, which is not so good. A finer crush, longer mash and/or more stirring during the mash could help increase your conversion efficiency. Doing a single batch sparge will decrease your lauter efficiency, and using less grain will increase your lauter efficiency but result in a lower OG. Here's a chart that shows how lauter efficiency varies with grain weight to pre-boil volume ratio for different batch sparge counts.

View attachment 416026

Things you could do to increase your lauter efficiency:

1. Let all drainings run as long as your last draining. This would decrease your grain absorption rate from 0.125 gal/lb to 0.1 gal/lb
2. Do three batch sparges instead of two.

The first option would increase your lauter efficiency from 89% to 91 - 92%. The second (with sparges of 3 gal) would also increase your lauter efficiency to 91 - 92%. If you combine the two, your lauter efficiency would go to 93 - 94%. Not a huge gain for more work/time.

Brew on

Question on this graph...it says pre boil volume. Does this mean the volume in the kettle or the volume of strike and sparge water into the MLT?

 

[doug293cz]

Question on this graph...it says pre boil volume. Does this mean the volume in the kettle or the volume of strike and sparge water into the MLT?

Pre-boil volume is the amount collected in the BK. It is less than the total of strike plus sparge volumes by the amount of grain absorption and any undrainable MLT volume.

Brew on

 

[Bobby_M]

.125 is pretty high. Even if you put a little downward force on the grain when draining to get it down, especially on first runnings, you'll do better.

 

[doug293cz]

...

I also find that adding sparge water then letting it sit doesn't accomplish much. Add the sparge, stir, vorlauf then drain. No need to lengthen brewday letting the sparge water sit. Ultimately you are just rinsing the grains.

This is true if conversion is complete at the "end" of the mash. However, if you have incomplete conversion at the time of initial run-off, then wait time after adding sparge water can allow some additional conversion to occur. There is evidence that this happened in OP's case (incomplete conversion at end of mash and higher than expected third [and maybe second] runnings SG.) Much better to improve crush to get complete conversion in less than one hour, than to depend on additional conversion during the sparge, to boost your efficiency.

Brew on

 

[lslbrew]

.125 is pretty high. Even if you put a little downward force on the grain when draining to get it down, especially on first runnings, you'll do better.

It did seem high to me too. I have been getting .08. Since I had double milled the grain and got more smaller pieces I was thinking that maybe the absorption went up (more exposed grain was able to take up more water). Since I had changed one variable, the milling, I wasn't sure if that was expected or not without doing another batch.
I am trying to walk a tight rope between two mutually exclusive concepts, making my brewing day more efficient both in actual work and starch conversion and creating consistency so I can calculate temp, water, grain amounts, etc and hit all my numbers. I guess that means that I just need to brew more so I can double check all my assumptions. :rockin:

 

[GHawk]

I use Promash, measured from fermenter, sample pulled as I fill from counter flow chiller. Long, slow dough in, lots if stiring, stir some more, and 60 minute mash with 2 degree loss.
Consistent 77-78% eff. With occasional low 80's. 80's the last few years.
To me, its about the crush, dough in, and mash temp.