Monday, September 16, 2013

A Homebrewing Perspective on Mash pH II: Water

Here is the companion paper to my first paper on mash pH (see previous post).  Entitled A Homebrewing Perspective on Mash pH II:  Water, this paper continues with analysis of Kai Troester's experimental work mash pH, and along the way discusses some useful concepts such as residual alkalinity, ion concentration, and normality.  Again, the three spreadsheets EZ Water, Brun Water, and Kaiser Water are discussed.  The paper ends with some suggestions for adjusting mash pH when starting with distilled or reverse osmosis water.

As usual, thoughts, comments, and questions are all welcome. Cheers!


  1. Hi Mark,

    Your papers on mash pH and the comparisons of several popular water adjustment spreadsheets in use are clear, informative and answered a few queries I had regarding the discrepancies I've seen between them. I've found your estimates to be the most accurate (as measured with a Milwaukee MW102), especially when I use lactic acid instead of acidulated malt. However, I find the Bru'n water layout and feature set much better for my workflow and record keeping so I continue to use it having a pretty good idea now of the offset it predicts and occasionally use your latest spreadsheet as confirmation. I have several suggestions to improve the functionality of your spreadsheet if you are interested. The key one being the option to enter mineral additions as a concentration so the pH can be dialed in and then the additions scaled to account for the recoverable volume under the mash tun screen (3.5 L in my case).

    Thanks and regards,
    kiwi brewer

    1. Kiwi Brewer,

      I'm glad you find the papers informative. It's also nice to hear the pH predictions are reasonably accurate and therefore helpful.

      I am happy to hear any of your suggestions. I'm not quite sure about the one suggestion you've made. Are you saying you would like the mineral additions to be input as ppm? I'm also not sure about the significance of the "recoverable volume un the mash screen." If you could perhaps explain how BrunWater works better for you, then that might help me understand. Cheers!


  2. Hi DMR,

    I posted a lengthy reply about a week ago which appeared to be accepted but it still hasn't shown up here. Do you approve posts first? No worries if this is the case, I'd rather discuss privately anyway.

    1. kiwi brewer,

      You post was most definitely here, but apparently only for a little while. I do not know why it disappeared; I did not delete it. I really appreciate the feedback! I'll certainly consider it in the next update of the MpH spreadsheet. Strange...


    2. kiwi brewer,

      I'll repost your remarks here, just so I know where to find them. I have looked through them, but I'll probably have some questions in the future. Thanks again!


      "Hi Mark,
      What I like about Bru’n water (in no particular order):
      • Ability to choose metric or imperial for both volume and weight.
      • Ability to select EBC or Lovibond.
      • Mineral additions are in g/L or mL/L (ppm) which then adjusts totals if water volumes are adjusted.
      • Toggle for removing crystal and/or roast malts from the main mash (e.g., if added at vorlauf per Strong or steeped separately).
      • A field for beer name for archival purposes.
      • Ability to change acid malt strength (this is in the full version).
      • Beer colour estimate (the same as I get in my own spreadsheet and appears more accurate than BeerSmith).
      • Ability to load a target water profile for comparison.
      • Ion concentration conversion and hardness to bicarbonate calculators.
      • Nice summary page for printing.

      What I have issue with:
      • pH estimates are very sensitive to water to grist ratio which KT’s data implies is not the case.
      • Strike water acid additions overestimate mash pH reduction by 0.1 - 0.2 pH (confirmed with pH measurements).

      Wish list:
      • A distilled water mash pH estimate (this can be gotten by diluting the mash with 100% DI water which is how I’ve compared against your estimates).
      • Ability to verify calculations (i.e., unhide them).

      Your spreadsheet has provided a more accurate estimate based on two batches, both of which used ~1.5 ml of 88% lactic acid in the mash. I also use acid malt in lieu of lactic acid and will be gathering more data this summer. The BW prediction using acid malt has been much closer to what I measure. I found your papers and spreadsheet while doing initial research into why I was seeing the big discrepancy in pH predictions when using lactic acid.

      Implementing any of the items listed above for Bru’n water would make your spreadsheet more universal and add to the functionality but I understand that may not be your intent. Also, since you have included the equivalent PK RA calculations, a toggle to switch between the PK and KT results for pH estimates would be useful when comparing against measured results (i.e., for further testing as you suggested is warranted). Regardless, these are changes I can make by developing my own using your equations. One of the features of your spreadsheet I really like is the pH estimate for each stage of the process (DI, + strike water, + salts, + salts and acid). It is a bit cumbersome duplicating this in BW.

      Regarding the recoverable volume under the mash, my system is essentially a RIMs type of mash unit where the volume under the screen is kept at the desired mash temp (or heated to the next one) while being continuously pumped to a screen above the mash. The water to grist ratio with the mash is 2.7 L/kg and the volume below the screen is ~3.5 L. So with a 5 kg mash, the strike water would be 17 L but only 13.5 L would be in contact with the mash at any one time. Your spreadsheet (and the latest one by KT on Brewer’s friend) is relatively insensitive to mash thickness when the concentration of salt additions are maintained the same as you mentioned in the grist paper. BW is very sensitive to this and gives much different results if I select 13.5 L or 17 L. Selecting 17 L gives me the most accurate result. I should note that my water is quite soft and often the salt additions alone essentially neutralizes the RA in the water so mash pH with salts ≈ distilled water mash pH.

      Hope this provides some insight to a least part of your user base and thanks again for taking the effort to review the available data and spreadsheets and produce the three papers on the subject. Even if I end up just developing my own spreadsheet, your work has been invaluable and greatly appreciated."

    3. Hi Mark,

      You are welcome. As a follow up, I brewed a session ale with acid malt over the weekend that also included crystal and roasted malts. 4 kg grist with 40 g of acid malt. At 1% of the grist, the NZ maltster says the mash pH will drop by 0.1 which both your spreadsheet and BW predicted. I measured 5.30, BW predicted 5.32 (with full mash water volume) and yours 5.4. I took measurements at 15 min and again at the end of the mash and both were essentially the same. The meter was calibrated prior to the first measurement.

      So if I use acid malt and include the full mash water volume, BW is fairly accurate (this is consistent with previous observations). If I adjust for the actual water to grist ratio and/or use lactic acid, the predicted pH is 0.1 - 0.2 pH low.

      kiwi brewer