Homebrew Water Chemistry and the Nomograph

Update: For those of you looking for brewing water profiles, download the water salt calculator Excel table. Not only does this have a list of famous water profiles, but it will semi-automatically calculate water salt additions to create these profiles. Also, this calculator has been updated so the profiles page comes up first, not the calculation engine.

Every now and then something comes along that really blows the top of your head right off. For me, one of those things is the nomograph. In an age where there is an online calculator for every conceivable thing (including, I'm sure, conception), it is satisfying to find that pen and paper can still produce a more efficient and elegant method of deriving data. A nomograph is a set of calibrated rulers. By plotting values on several of these rulers and linking the points with straight lines, the commensurate values of the remaining rulers are derived. I came across this while researching the chemistry of mash water to fine-tune my homebrewing process.

To use the homebrewer’s nomograph, magnesium and calcium ion concentration are plotted to derive effective hardness, and this value is combined with alkalinity to determine mash pH. John Palmer, author of a very useful homebrewer's manual and the creator of this nomograph, has thoughtfully included a color-coded scale above the pH ruler to emphasize the proper mash pH for the various hues of beer. This is not only very cool but very useful to the grain-based homebrewer, as it allows an easy assessment of the effects of water chemistry on mash pH, and therefore, on the suitability of a particular water for brewing different types of beer. I have taken this tool and overlaid on it the calculations for the worlds major brewing waters. (Follow this link for a powerpoint version of these graphs) It is fascinating that the beers these cities are famous for generally follow the trend indicated by the mash pH resulting from the water. For example, Pilsn and Burton-on-Trent have turned out the worlds best pale lagers and ales, while Dublin is famous for its coal-black stout. Everyone else falls somewhere in between. It's also interesting that there is more than one way to get to the optimal pH for a light-colored beer. The water in Plzen (Pilsn) has little ionic content, and is thus ideal for the delicate Pilsner style (the true pilsner, not the cheap imitation that American macrobrews turn out). On the other end of the scale, Burton-on-Trent's massive calcium load aims it squarely toward the low pH as well. (Burton's concomitantly high sulfate load also plays an important role in the hoppy character of the region's classic pale ale - it both accentuates and improves the bitterness of the hop.) To illustrate how this is used in homebrewing, I have plotted my standard water profiles for light, medium, and dark-colored beers.

To determine how to adjust our well water to generate these three profiles, I created an Excel-based water salts calculator. This calculator is set up to be useful to any homebrewer - once you have entered your base water profile (this should be available from your water supplier, or from a water analysis of well water) and have tuned the conversion table to generate the appropriate profiles from this base water, simply entering the volume of water that you need will provide you with the amounts of gpysum, epsom salts, chalk, and/or salt needed to achieve each standard profile (For those who want to go "under the hood", the engine that drives the ppm/tsp conversion is in the second tab of the Excel file). Though I do not use them, I have also included conversion calculators for utilizing baking soda (sodium bicarbonate) and calcium chloride, as a service to those homebrewers who do. Yes, I know that ProMash, BeerTools, and other brewing software have calculators that can do these things as well, but I prefer to get in and mess around with the calculations directly. This spreadsheet allows you to easily do that.

For those of you who are using tap or well water that is naturally high in the important brewing ions, you can still approximate at least the correct mash pH, by using the nomograph to adjust the important parameters. Of course the ions listed in the calculator, along with the various counter-ions, have additional important roles in hop utilization and flavor perception and history has shown that deviating from these profiles can cause suboptimal results. For the best possible beer, I would suggest using distilled or spring water for at least some of your brewing liquor, to lower the base ion content (Alternatively, find a friend or relative with a favorable water profile and fill a couple of 5-gallon jugs there for your brew day needs!).

I originally set out to create a calculator that would do the first part for you - calculating the desired tuning conversion table automatically, but that turns out to be very, very complicated, as there are multiple ways to achieve each water profile. Though not quick, providing both the base profile and the conversion table allows for the most flexibility and usefulness in the calculator. Once it is set up, brew day adjustments are a breeze, and I firmly believe that proper mash chemistry is one of the factors that has allowed us to consistently produce award-winning homebrew.