Author Topic: pH adjustment in BeerSmith using mineral salts and acidulated malt  (Read 1798 times)

Offline Oginme

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Standard disclaimers:  This is how the software and outcomes work on my system based upon my inputs and process.  I am using past data for analysis to compare the affect of inputs to the grist and mash water on the predicted pH as estimated by BeerSmith. YMMV.

So, I've been poking around at the mash pH prediction in BeerSmith 3 for a little while now.  I typically use only mineral salts and acidulated malts to target my pH and have been fairly successful in the past at coming pretty close to target using a combination of Bru'n Water and BeerSmith.  I have also tested EZWater and the latest spreadsheet, Mash Made Easy just for kicks and to see how they differ.

I will comment here that I typically use 3 base malts which I purchase in full bags:  Weyermann Floor-malted Pilsner, Crisp Maris Otter, and Rahr 2-row.  I stick with these because they are consistent and predictable in flavor, gravity, and color as well as affect on pH. 

My use of acidulated malt is based on the ease of use and, again, the predictability in my process.  I can dial in the pH to my standard target for most recipes of 5.4 using the recommended additions from the Weyermann web site of 1% Acidulated malt in grist = 0.1 drop in pH units.  Over the past four years, this has relationship has been verified and easily repeated in my system. 

My water is well water which has been very stable over the past 5 years that I have been testing it.  I run a test using the LaMotte kit twice a year, usually at the beginning of my brewing season in October/November and somewhere in the middle around February.  Test results are all plotted and I use the average of all tests for my water profile.  There has been no change in mineral/ion concentrations over the past 5 years I have been testing within the parameters of the test accuracy and the testing matches the original test performed by Ward Labs.

Water quality:  Ca: 9.5 ppm, Mg: 2.7 ppm, Na: 71.8 ppm, SO4: 7.2 ppm, Cl: 107.5 ppm, Bicarbonate: 35.1 ppm

I picked a simple recipe: a classic German Pilsner because it is simple and has not been changed over the 4 years that I have brewed it.  It gives me a chance to ground the readings in real data without any adulteration to the recipe in order to compare real results with the predictions from the software. Since I also made these all with a full volume BIAB, it keeps the calculations pretty simple.

Given this water and a malt bill of 98.5% Pilsner and 1.5% Melanoidin malt, the predicted pH from Bru'n water (which I was using at the time I first brewed this lager) with additions of 1.96 g of Epsom salt, 1.95 g of Calcium chloride, and 1.66 g of Gypsum into 15.4 liters of water was 5.58.  Opening up this same recipe in BeerSmith from my archive, the water tab shows a predicted pH of 5.63.  My actual result at 15 minutes into the mash was 5.61, pretty much splitting the difference. 

The following year, I brewed the same recipe with the addition of 40 g Acidulated malt thus making the grain bill 96.6% Pilsner malt, 1.4% Melaniodin malt, and 1.9% Acidulated malt.  Bru-n water predicted the pH to be 5.48.  This recipe opened up in BeerSmith predicts the pH to be 5.51.  Actual result was 5.43 at 15 minutes into the mash.

To reach a target pH of 5.43 in BeerSmith, I need to increase the amount of acidulated malt to 80 grams which then corresponds to 3.8% of the grist.   

In overall comparison using the other water tools available, EZ water gave me a predicted pH on the original recipe and brew (Pilsner, Melanoidin malt, and mineral salt additions) of 5.69.  Mash Made Easy predicted the pH to be 5.45.

Using the next brew containing acidulated malt and plugging that into the other water spreadsheets available, Bru'n water predicted a pH of 5.48; EZ Water gave me an estimation of 5.43; and MME predicted the pH to be 5.25.  While the EZ Water spreadsheet was nuts on for the prediction with the acidulated malt, it started from a higher predicted pH which was out of the accuracy of my pH meter using just the water, grist and mineral salt additions.

Overall, I think the 'big 2' (Bru'n water and BeerSmith) are pretty close for the mineral salts additions.  Given that water chemistry is a pretty complex interaction of many different components which extends far beyond the basic 6 which are taken into account for predictions, these are not too far off the mark.  Also, the accuracy of my pH meter is to within 0.05 pH units, so the actual pH could easily fall to any one of the three.  I've written off the Mash Made Easy spreadsheet as it is too far from the others to be relied upon.

I had switched to using BeerSmith for the mineral salt water adulteration of my well water pretty soon after Brad added that capability for pH estimation in BS2.  I make my acidulated malt adjustments based upon the Weyermann recommendations, since that has served me well. 

The acid additions that everyone has been pointing out the differences between Bru'n Water and BeerSmith, I cannot comment on, other than stating that the acid contribution from the acidulated malt is out of proportion with manufacturers recommendation and my own experiences by about 2x overstatement of required amount.  Bru'n Water, while coming in just within the accuracy of my pH meter for this recipe, also seems to overestimate the amount of acidulated malt (70 grams) needed to replicate actual results by nearly the same margin as BeerSmith did. 

So the bottom line (at least for me) is that you can get pretty close with the mineral salt additions and then use your own experience and practice to dial in exact pH if you choose to use aciduated malt or other acids.  This, BTW, pretty much matches my experiences with trying to control the pH on paper machines.  While theory is nice, you have too many variables to rely fully on the model and need to dampen the output response to ensure you don't drive your process out of control.

Another note of relying on pH predictor models:  I chose this recipe because it is simple and has been unadulterated.  My go-to base malt for American styles is Rahr 2-row.  When I use the Rahr 2-row, I change my pH target from 5.40 to 5.60.  Experience and data from using this malt indicates that this target value will net me a mash pH of 5.40 to 5.45 every single time.  When I tried Briess Brewer's malt for a while, I needed to change the pH target back to 5.40.  Base malt choices do matter and no available software will break down that fine detail enough to compensate for every option we have available to us as brewers. In short, NEVER rely totally on a machine, program, or model to give you exact answers.  The world is just not that nice and predictable for us.

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Offline BeerSmith

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Re: pH adjustment in BeerSmith using mineral salts and acidulated malt
« Reply #1 on: July 11, 2018, 07:49:44 PM »
For acid malts the calculation is actually pretty straightforward, but it is important that you have the acid percentage set correctly as it will vary depending on the malt used.  Most have an acid content around 2% (the default) but some vary.

If you want a detailed comparison of the various options and how well they replicate the chemistry you should read both of these papers.  BeerSmith uses the model described in the papers.  Read both part I and II:
   http://homebrewingphysics.blogspot.com/2013/09/a-homebrewing-perspective-on-mash-ph-i.html

Brad
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