Author Topic: Water adjustment for very thin mashes  (Read 3275 times)

Offline hhb

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Water adjustment for very thin mashes
« on: September 16, 2012, 10:24:04 AM »
I have been a BIAB brewer for a while, and now I have started looking into water adjustments.  My preference is to use the Kaiser Water Calculator, but the PH calculation is not done for mash thickness above 5 l/kg.  Brewing a low ABV (4.5%) beer can bring me up to a mash thickness of 8 l/kg.

I can split the water and do a dunk sparge, but for convenience I would like to mash with the full water volume.  I have considered calculating the PH with a mash thickness of 5 l/kg, and then adjust the water such that the calculated mash PH is 0.1 lower to account for the increasing PH with thinner mash.  This adjustment would have to be higher for darker beers.

Would appreciate any comments or thoughts on this.

Offline nateo

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Re: Water adjustment for very thin mashes
« Reply #1 on: September 16, 2012, 10:49:09 AM »
I think Bru'n Water may work better for you.
In der Kürze liegt die Würze.

Offline hhb

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Re: Water adjustment for very thin mashes
« Reply #2 on: September 16, 2012, 11:49:08 AM »
Using a mash thickness of 4.9 l/kg I get the following mash PHs:
Kaiser 5.4
Brun 5.7
EZ 5.8

The variation is more than I like.  The above numbers are all with very soft water with no adjustment.

Offline nateo

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Re: Water adjustment for very thin mashes
« Reply #3 on: September 16, 2012, 11:59:08 AM »
Are you actually measuring the pH or just guessing?

I typically mash between 3.5-4.5L/kg and verify pH with a pH meter. Bru'n water has almost always been within +/-0.1 pH units for me with pretty soft water, though I've had one or two times it was off by 0.2.
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Offline mabrungard

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Re: Water adjustment for very thin mashes
« Reply #4 on: September 16, 2012, 01:09:47 PM »
Using a mash thickness of 4.9 l/kg I get the following mash PHs:
Kaiser 5.4
Brun 5.7
EZ 5.8

The variation is more than I like.  The above numbers are all with very soft water with no adjustment.

Soft water is meaningless.  What is the water's alkalinity.  Hardness is generally not an issue in brewing.  Alkalinity ALWAYS is!

Bru'n Water's calculation on mash pH is directly affected by the volume of water in the mash.  It should be fairly accurate for that use.
« Last Edit: September 16, 2012, 01:13:58 PM by mabrungard »
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Offline Kaiser

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Re: Water adjustment for very thin mashes
« Reply #5 on: September 16, 2012, 04:23:49 PM »
hbb,

Welcome to the forum.

The mash thickness limitation in my water calculator became obsolete after I changed to a new formula for predicting the grist's pH. I forgot to take it out and I just took care of that.

The grist pH that is calculated does not depend on mash thickness anymore. Mash thickness affects the predicted mash pH by changing the amount of residual alkalinity that is present for a given unit of grain. You'll see that if your mash thickness doubles, the pH shift caused by the water doubles.

Kai

Offline hhb

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Re: Water adjustment for very thin mashes
« Reply #6 on: October 05, 2012, 10:55:36 AM »
Thanks for updating the calculator.  I have relooked at my calculations (all the numbers above were calculated based on same grist and water) again and found that I had some acid malt that I had forgotten to delete.  The numbers are now closer (Kaiser 5.6, Brun 5.7 and EZ 5.8).  My alkalinity is 0,9-1,0 mmol/l as reported by the local water supplier.

I was hoping to be able to just calcluate the ph and live with strips, but I now also realize that the boil & cast out ph is important so I now plan to get a meter.  The only local commercial brewery shared a recipe and I noticed they added CaCl and Lactic Acid both to the mash & boil at a ratio 3:1.  I have found some articles but there appears to be less than those covering mash ph.  I would appreciate any suggestions on what to read.

Looking forward to brew a pale ale tomorrow.  Hopefully the hops will come out better than in the past with the water adjustments.