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Author Topic: Water to grain ratio for mash tun.  (Read 62243 times)

Offline tomsawyer

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Re: Water to grain ratio for mash tun.
« Reply #75 on: March 21, 2011, 07:12:11 am »
Lennie,  did you see a change in efficiency compared to your usual procedure?
Kai
Kai, with my "conventional" 1.5-2qt/lb and a batch sparge, I'd get anywhere from 75-80% typically.  If I mashed at 2qt/lb I'd drain off 1.5qt, that should give me 75% right there.  A sparge would bring me to 90% theoretically.  I have almost no dead space in the tun and I drain it thoroughly.  I have to attribute my results as coming from differences in conversion.  I seem to be losing upwards of 10% of my sugar in the thicker mash.  This is in spite of my fairly fine crush and extended mash time.  I did see another 5% when I started doing a short beta rest/mashout so I knew I was leaving some behind.  The beta rest gives me a less dry beer though so its not a universal way of improving my efficiency.  Decoction also worked and I could get a dry product with this method but its more work.

Is this right?  3qt/lb for the first, 3.2 for the second?  I would think that 0.2 qt/lb wouldn't really be the difference between thick or thin.

These were both thin, they were replicates not a control and an experiment.  I only did 3.2 so I wouldn't need to add additional water to the kettle.
On the first I used a 3qt/lb mash ratio and got 75% efficiency preboil.  On the second I used 3.2qt/lb and also got 75%.
Is this 75% with No-Sparge?  That's about what I see mashing thin without a sparge, depending on the amount of grain.
Yes I mashed with all my water, then just drained and boiled.
Lennie
Hannibal, MO

Offline Kaiser

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Re: Water to grain ratio for mash tun.
« Reply #76 on: March 21, 2011, 07:40:58 am »
Quote
Kai, with my "conventional" 1.5-2qt/lb and a batch sparge, I'd get anywhere from 75-80% typically.  If I mashed at 2qt/lb I'd drain off 1.5qt, that should give me 75% right there.

Lennie, I’m running these numbers (1 lb , 2 qt) through my batch sparge simulator and I’m getting only 68% on the 1st run off (assuming 0.12 gal/lb absorption). The run-off volume is 1.5 qt. It also assumes 100% conversion efficiency.

To make a ~ 12Plato beer with 15% boil-off I have to add 1.2 qt/lb sparge water. This additional batch sparge bumps efficiency by ~20 points to 88%. In the end you get 2.7 qt @ 10.3 Plato pre boil wort.

With 0.1 gal/lb grain absorption, I get 72% efficiency with the first runnings and 90% if you combine both 1st and 2nd runnings.


Quote
I seem to be losing upwards of 10% of my sugar in the thicker mash.  This is in spite of my fairly fine crush and extended mash time.  I did see another 5% when I started doing a short beta rest/mash-out so I knew I was leaving some behind.  The beta rest gives me a less dry beer though so its not a universal way of improving my efficiency.  Decoction also worked and I could get a dry product with this method but its more work.

You may want to fill out portions of the efficiency spreadsheet. I’m using this on almost every batch to calculate my efficiencies since it also corrects for temperature and can tell me what boil-off I need to aim for to get my target gravity. It also tells me how much conversion efficiency I’m getting. If I’m still well below 100% I tend to give the mash more time or raise the mash temp. I know that if I don’t take care of that problem right there I’ll likely miss my target gravity.

Do you happen to have a record of your first wort gravities? That and mash thickness is what you’ll need to calculate conversion efficiency.

Kai

Offline tomsawyer

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Re: Water to grain ratio for mash tun.
« Reply #77 on: March 21, 2011, 10:26:47 am »
I see, I was just going by my own simplified version of an efficiency calculation.  I use 0.125gal/lb (0.5qt/lb) absorption.  I don't have first runnings measurements, I haven't been taking those since I've had consistent results that I thought were adequate as far as sugar recovery.  Since I'm getting something similar with this 3+qt/lb method I might continue with it for the time being, just to see if theres a difference in beer quality.  It would seem that it could only help, not hurt, and its easier to just heat water once and then run it all off.  The few points difference between this and batch sparging, doesn't seem to make a huge difference.

I thought my 75-80% efficiency was pretty typical for a batch sparge.  It always made me wonder why I wouldn't get closer to the 88% you've got as a predicted amount, I think incomplete conversion is the most obvious answer.  I've let the mash go for two hours before and still only get my usual efficiency.
« Last Edit: March 21, 2011, 12:58:17 pm by tomsawyer »
Lennie
Hannibal, MO

Offline tomsawyer

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Re: Water to grain ratio for mash tun.
« Reply #78 on: March 21, 2011, 10:50:31 am »
I played with your calculator a bit.  it looks like with my conventional 2qt/lb batch sparge I'm probably getting in the range of 83-88% conversion.  With the 3qt/lb it looks like I got 95% conversion.
Lennie
Hannibal, MO

Offline Kaiser

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Re: Water to grain ratio for mash tun.
« Reply #79 on: March 21, 2011, 12:31:50 pm »
I thought my 75-80% efficiency was pretty typical for a batch sparge.  It always made me wonder why I wouldn't get closer to the 88% you've got as a predicted amount, I think incomplete conversion is the most obvious answer.  I've let the mash got for two hours before and still only get my usual efficiency.

Lennie,

The good thing is that you have something that works. Over the next few batches you can take a few more measurements to figure out where your losses are. Then you can decide if it is worth doing something about these losses.

Kai

Offline tomsawyer

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Re: Water to grain ratio for mash tun.
« Reply #80 on: March 21, 2011, 01:19:37 pm »
True, things are quite predictable.  I''ve always wondred why I'd get 75% efficiency when a simple two step extraction would suggest a higher recovery.  Now I know its got to do with conversion being product inhibited.  I found an article on product inhibition of alpha-amylase that says its 50% inhibited by 100g/L.  A 1.046 wort is 120g/L.  Plus theres temp degradation of the enzyme so you just can't leave it to mash for hours and get complete conversion.

http://www.springerlink.com/content/n17r1h56h2681251/
Lennie
Hannibal, MO

Offline malzig

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Re: Water to grain ratio for mash tun.
« Reply #81 on: March 22, 2011, 04:41:02 am »
I''ve always wondred why I'd get 75% efficiency when a simple two step extraction would suggest a higher recovery.  Now I know its got to do with conversion being product inhibited. 
Well... that's certainly a factor, but these days I can get close to 100% Conversion Efficiency with a No-Sparge or a Batch Sparge, so it's not an absolute. 

For a 12°p beer, my real-world numbers give me ~75% Mash Efficiency by No-Sparge with a 3 qt/# mash (or a 2 qt/# mash and an added alpha-amylase rest at 3 qt/#, which can be slightly more efficient for me), or 87% from a 2 qt/# mash and a Batch Sparge.

Offline tomsawyer

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Re: Water to grain ratio for mash tun.
« Reply #82 on: March 22, 2011, 05:52:16 am »
Well... that's certainly a factor, but these days I can get close to 100% Conversion Efficiency with a No-Sparge or a Batch Sparge, so it's not an absolute.  

For a 12°p beer, my real-world numbers give me ~75% Mash Efficiency by No-Sparge with a 3 qt/# mash (or a 2 qt/# mash and an added alpha-amylase rest at 3 qt/#, which can be slightly more efficient for me), or 87% from a 2 qt/# mash and a Batch Sparge.

Whats the secret?  And how do you calculate conversion?  Everything soluble converts so the iodine test seems to me to be slightly misleading.  And, do you find any qualitative differences between the beers?  Assuming you can hit similar OG/FG with the two processes.

Next time I do one of these I'm going to use 3.7qt/lb which will give me full preboil volume, and I'm going to check the progression of the conversion every fifteen minutes with a refractometer.
« Last Edit: March 22, 2011, 05:55:28 am by tomsawyer »
Lennie
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Offline Kaiser

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Re: Water to grain ratio for mash tun.
« Reply #83 on: March 22, 2011, 08:07:09 am »
Lennie, here is something about calculating conversion efficiency:http://braukaiser.com/wiki/index.php/Troubleshooting_Brewhouse_Efficiency#Determining_Conversion_Efficiency

extract that has not contributed to conversion efficiency tends to be still bound in the grits of the mash.

Kai

Offline malzig

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Re: Water to grain ratio for mash tun.
« Reply #84 on: March 22, 2011, 06:38:33 pm »
Whats the secret?  And how do you calculate conversion?  Everything soluble converts so the iodine test seems to me to be slightly misleading.  And, do you find any qualitative differences between the beers?  Assuming you can hit similar OG/FG with the two processes.
I don't think there's a magic secret to getting full conversion.  The biggest factor is crush, but a warm alpha rest and a thinner mash can push that last reluctant 10% or so to convert or help make up for a less than optimal crush.

The calculation for conversion efficiency is a little bit of a pain, because of the volume contribution from the sugar.  The easiest way is to use Kai's chart that shows the gravity of the first runnings for a given mash thickness at 100% conversion:


I find the iodine test to be just this side of useless.  It certainly won't tell you if you have complete conversion.

As far as qualitative differences, I do get different OGs, of course, but I guess that's quantitative.  Other than that, I've been using No-Sparge for Lagers and British Ales, and I get a nice malty but soft malt profile, which is why I chose to use that technique, but I've never made the same recipe both ways to make the comparison.  I don't expect there's a huge difference in flavor, though.  More than anything else, it's just a little easier and a little faster than bothering to sparge and, at 75%, it only costs 1 # of extra grain for 5 gallons of a 12°p beer.

Offline oscarvan

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Re: Water to grain ratio for mash tun.
« Reply #85 on: March 22, 2011, 07:36:48 pm »
I taste the wort..... I know not very scientific. But it does tell me there's a metric crap load of sugar in there, and in the "artisan tradition" that's close enough.
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Offline tygo

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Re: Water to grain ratio for mash tun.
« Reply #86 on: March 22, 2011, 07:52:14 pm »
a metric crap load of sugar

How many degrees Plato is one metric crapload ?  ;D
Clint
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Offline Kaiser

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Re: Water to grain ratio for mash tun.
« Reply #87 on: March 22, 2011, 08:04:52 pm »
Since I wrote those efficiency articles I have come up with a better formula for CE that doesn't go though the table Malzig mentiones. Though the table is still useful to get an idea how stong of a FW one can get.

CE = extract potential * (100 – Plato) / ( Plato * R )

where
* extract potential is the grain's extract potential in %. This needs to be the "as is"  extract potential that includes the moisture content i.e DBFG * (1-1/MC) . DBFG - dry basis fine grind extract in %, MC - moisture content in %. 80% is a good estimate for the "as is" extract potential.
* Plato is the mash wort strength in Plato
* R is mash thickness in l/kg

These calculations are best done with metric values and under the hood my spreadsheet does everything with Plato and metric units.

Kai

Offline oscarvan

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Re: Water to grain ratio for mash tun.
« Reply #88 on: March 22, 2011, 08:24:02 pm »
a metric crap load of sugar

How many degrees Plato is one metric crapload ?  ;D

Hot, very hot.
Wooden Shoe Brew Works (not a commercial operation) Bethlehem, PA
http://www.woodenshoemusic.com/WSBW/WSBW_All_grain_Setup.html
I brew WITH style..... not necessarily TO style.....

Offline denny

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Re: Water to grain ratio for mash tun.
« Reply #89 on: March 23, 2011, 09:19:58 am »
I find the iodine test to be just this side of useless.  It certainly won't tell you if you have complete conversion.

It's amazing how this fallacy has perpetuated itself through the years.  Between the high possibility of false readings and the lack of useful info, I tell new brewers to just forget the iodine test even exists.
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