Water Chemistry

by Elvis (Mike Karnowski)

Last week I spoke to a customer excited to embrace his inner brewer and create his own recipes.  He had carefully calculated his base and specialty malts, researched alpha acids and aroma characteristics and even sought out just the right yeast to tie everything together.  It was an impressive recipe.  But something was missing.  I asked “and what about your water?”  “What about my water?” he said.  Water accounts for 90-95% of your beer yet it’s the one ingredient we rarely think about on brew day.     

Understanding how water affects beer can take your recipe from good to great, but taking it for granted can render an otherwise great recipe underwhelming.  In general, if your water tastes good or better yet, doesn’t taste at all, you’re probably in good shape.  But if you have a water softener in your house or find yourself filtering your drinking water you might want to start treating your water more like an ingredient than an afterthought. Remember: Good In = Good Out.    

A common misconception in brewing is that hard water is bad.  Calcium and Magnesium, the minerals that attribute to hardness, are actually essential for yeast health and also help to promote clarity and shelf life.  But there is some truth to the old adage “too much of a good thing…” so if your water tastes minerally or leaves scale on your drains the easiest way to prep your water for brew day is to dilute it 1:1 with distilled, deionized or reverse osmosis water which can often be sourced from your local grocery.    

For extract brewers, Chlorine and Chloramine are probably the most detrimental to beer flavor.  Filtering with a carbon filter or treating your water with a Campden tablet will eliminate the potential for Chlorophenols that impart a medicinal or Band-Aid-like flavor.  Other mineral additions or dilutions can help to hone in a recipe but are far less influential.  

So how do we find out what’s in our water?  If you’re connected to a municipal water supply it shouldn’t be difficult to get a water report.  Often, these reports are available for free on their website.  If not, give a call.  Federal law requires that all public drinking water falls within certain guidelines indicating what can and cannot be in water and at what levels.  The information on this general report is good but not as specific to what we, as brewers, are looking for.

Homework Exercise:  Contact your local water supply and ask for the numbers (in parts per million) for Calcium, Magnesium, Sulfate, Chloride and Sodium.  You’ll also need pH, Total Hardness and Alkalinity as CaCo3 (Calcium Carbonate).  Now it’s time to break these numbers down and teach you how to use them to your advantage so that your good recipes turn out great on your next brew day.  

CaCO3 & pH

Earlier I mentioned how minerals like Calcium and Magnesium contribute to healthy fermentation, clarity and flavor stability.  Now we’ll identify the ideal concentrations of each, address brewing salt additions and explore the effects of pH and alkalinity on your mash conversion.  Finally, I’ll explain how to use different ratios of chloride to sulfate to accentuate certain ingredients in your recipe.  

Remember, hardness (expressed on your water report as “Total Hardness as CaCO3”) is not a bad word in brewing.  Calcium and magnesium are the two main ions that contribute to hardness.  Both are necessary for yeast health.  Calcium is also responsible for helping to promote enzymatic activity in your mash as well as other biochemical reactions.  The optimal brewing water range for Calcium is 50-150 ppm and for Magnesium, 10-30 ppm.  Magnesium additions are seldom needed as malt usually contributes enough magnesium to reach these ideal concentrations.  

There are several great (and free!) brewing water calculators available online.  Start by inputting your own water’s data and then adjust to these ideal ranges as needed.  If your calcium concentrations are lower than the ideal range, just a few grams of Gypsum (Calcium Sulfate) or Calcium Chloride can make a big difference.

Be aware of the other ion in each compound (sulfate and chloride) as these concentrations will also be affected.  If your concentrations are higher, you might consider cutting your water source with distilled, deionized or reverse osmosis water.  A 1:1 dilution will cut your concentrations in half.  In most cases, this should get you within an acceptable range for brewing.  

Alkalinity and pH are often confusing terms for all grain brewers.  Alkalinity (expressed as either “Total Alkalinity as CaCO3,” “Bicarbonate” or “HCO3”) represents the concentration of anions like bicarbonate in your water and can be problematic at levels over 250 ppm.  Alkalinity acts as a pH buffer.  The higher the concentration the more resistant to change your mash pH will be. Ideal mash pH should be between 5.1-5.5.  If higher, mash enzymes are still very active but tannin extraction from husk material is more likely especially around a pH of 6.0  A pH lower than 5.1 will hinder enzymatic activity, therefore, reducing efficiency and could potentially affect flavor.   

Brewers are more likely to find themselves battling high mash pH as a result of high alkalinity more than other factors.  The specialty malts in your recipe will help lower your mash pH but not drastically.  As the degree of roasting in specialty malt increases so does the acidity.

This acidity can help to counteract higher mash pH but if you’re still not in that 5.1-5.5 range you may need additional acid.  You can find acid in multiple forms including acid malt, lactic and phosphoric acid.  I like to keep a couple pounds of acid malt on hand for small adjustments.  How much should you use?  1% of your total grist by weight should lower your mash pH by one-tenth of a point.   Concentrations and results will vary depending on the acid you use and may take some trial and error to perfect.        

Brewing water pH can vary greatly depending on the source.  An ideal range is 6.5-8.5 but the pH of your water is far less important than the pH of your mash.  I recommend mashing in first.  Allow the mash to settle for 5 minutes.  Then take a pH reading and adjust appropriately.  

Chloride and sulfate ions can be used to steer the flavor profile of your beer in your intended direction.  Sulfate helps to accentuate hop bitterness.  Chloride will do the same for malt character.  A well-balanced beer’s chloride to sulfate ratio might be 1:1 but it still depends on your recipe.  To highlight bitterness, try increasing your ratio to 1:2 or 1:3.  Research has shown that some styles can be brewed with a ratio as high as 1:8 without encouraging harsh bitterness.  The ratio applies to chloride in a similar manner.  A chloride to sulfate ratio of 2:1 or 3:1 can help to accentuate a more malt-centric recipe.     

So, keep your calcium levels between 50-150 ppm, your alkalinity between 0-250 ppm, your mash pH between 5.1-5.5 and adjust your ratio of chloride to sulfate to the characteristics of the style you intend to brew.  After that, bring us a sample.  You know, for “sensory evaluation.”

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