Dial In Your Brewing Water No Matter The Source

Thanks for the great question about water. I will jump into the middle of the pool here and try not to stray towards the deep end where the abyss of things not relevant to homebrewing lies. The crux of your question is how does one determine the starting point with water, and like most things in life there are multiple places to find information about your water. One thing for certain is that water chemistry is often inconsistent within a locale because of seasonal fluctuations and variations among sources, especially if you live in a place that draws water from surface reservoirs and underground aquifers.

For the sake of simplicity, let’s assume you have water piped into your house from a fairly consistent source, such as one of the little ponds called the Great Lakes separating the U.S. from Canada. These lakes generally fall into the humongous category of lakes, are deep, and have really consistent water. If you are lucky enough to have access to this sort of water, you can obtain water analyses from your municipal water authority and have pretty good information because the test data likely don’t vary much throughout the year.

To more fully address your question requires paddling towards the abyss. Water test methods use a variety of methods, some rather old and some rather new, to determine the composition of water. In the old days, titration methods were the norm for water testing and general buckets were defined by how water components reacted in titrations. For example, water containing calcium and magnesium ions can be titrated with EDTA (ethylenediaminetetraacetic acid) in the presence of a color indicator to determine total hardness. The total hardness bucket is then labeled in terms of mg/L of calcium carbonate. Similar methods can be used to determine alkalinity (bicarbonate and carbonate), which is also expressed in terms of calcium carbonate. Water test kits are readily available to determine hardness and alkalinity, and many of the classic brewing rules about water were based on these two values. I really don’t think you are asking about how to do water chemistry in the kitchen, but I will press on a bit farther.

More specific methods can be used to determine the concentrations of specific ions in water. For example, total hardness is a measure of calcium, magnesium, and carbonate, but brewers often want to know the individual concentrations of calcium, magnesium, and carbonate/bicarbonate. Ion selective electrodes, specific titrations methods, atomic absorption spectroscopy (AAS), and inductively coupled plasma spectroscopy (ICP) are some the most common methods to provide more specific results about water. Although AAS and ICP require specialized and relatively expensive instrumentation, the methods are widely utilized because of their reliability, wide range of measurements recorded in a single run, and speed. Water labs running lots of tests are likely using some sort of spectroscopy for analysis. OK, enough of the esoteric stuff. Most brewers, including the majority of commercial breweries (by head count, not production volume) farm this stuff out because water analysis is specialized stuff.

Getting back to the practical, let’s start with adjusting the water flowing from your faucet. I think it is much, much easier to do water calculations by knowing the concentration of individual ions. The three ions with the most significance to brewers are calcium, magnesium, and bicarbonate/carbonate (I lump the last two together because they are essentially the same thing, and their identity is pH dependent). I will stick to the question here and totally avoid jumping into the rabbit hole about how to adjust water. You have asked about water measurements. Assuming you don’t have super-consistent ground water, you can buy water-testing equipment that uses specific reagent kits and a device that looks like a pH meter to run your own tests, or you can send your water out to a lab. I have some pretty strong opinions about where the boundaries of a hobby lie, and personally believe that performing water tests at home and/or sending water samples to a lab are pretty extreme measures for a hobby. But if that floats your boat, go for it and be prepared to use the information that comes back. Check out the topic of residual alkalinity to help frame these results.

Another method is to start with reverse osmosis (RO) water, a blank canvas for brewers more interested in beer than burets, indicators, and millivals (milli-equivalents), and add what you want to build your own water. My bias towards this method may be showing just a wee bit here. And I am certainly not alone with my love of RO water. Check out Gordon Strong’s recipes and guidance about water. He is a preacher of the KISS (keep it simple, smarty) method of water chemistry and exclusively suggests using RO water for homebrewing.

Just to demonstrate how easy water calculations can be, I am going to do a demonstration here without any reference books and a simple calculator. The demonstration is to calculate the weight of sodium chloride required to add 25 ppm of sodium to 1 liter of RO water. Simple explanations are easiest with bullets. So grab a liter of RO water and your salt shaker!

• What is meant by 25 ppm of sodium? A part per million is a measurement that is equal to 1 mg/L. Why is it called a part per million? Well, a liter contains a million milligrams (1 liter = 1,000 grams = 1,000,000 mg), and the concentration shorthand of 1 ppm is the same as 1 mg/L.
• That was half the battle because we have our water recipe . . . we need to add 25 mg of sodium to a liter of water. Just fetch the bottle of sodium. OK, that’s not real funny since sodium metal bursts into flames when dropped into water. But, you do have that salt shaker. When sodium chloride is added to water, it completely dissociates into sodium and chloride. We just need to know how much sodium, by weight, is contained in a measure of salt. That’s actually easy to calculate by knowing the molecular weight of sodium and chloride, or by simply Googling “the mass percent of sodium in sodium chloride.” I am old school and don’t use that sort of shortcut, but do whatever works best.
• Here is where I get to show off my awesome memory of useful facts from chemistry. No joking here, if chemistry was taught using beer as a model we would have lots of smart kids who would know how to calculate the amount of salt to add to brewing water. Sodium weighs ~23 g/mole and chloride weighs ~35.5 g/mole (g/mole is also known as atomic mass units and it’s one of the properties listed on the periodic table).
• Sodium chloride (table salt) has an atomic weight of 23 + 35.5 g/mole or 58.5 g/mole and sodium represents (23/58.5) 39% of the weight of salt.
• How much salt do we need? Easy peasy . . . 25 mg of sodium divided by 0.39 (mg sodium/mg salt) = 64 mg salt per liter of water is what the brewer ordered!
• To recap using the Google method . . . 25 mg sodium divided by 39% (the mass percent of sodium in table salt) is equal to 64 mg of salt. I have been told that repetition helps memory.

You can use this same method with all of the other salts in water as long as you know the molecular weights of calcium (~40), sulfur (~32), magnesium (~24), carbon (~12), oxygen (~16), hydrogen (~1) and the forms that various salts come in. This is starting to sound like a spreadsheet and luckily for the modern brewer there are many very great water tools available out and about.

Every so often I get a question like yours Doug, where I get to jump up on my salt shaker and proselytize about using RO water. To sum this up, you can invest in water testing equipment and/or farm-out water tests (I forgot to mention that having your own equipment means getting a second set of measures to validate your home method), more or less frequently depending on the consistency of your incoming water, and blame the lab when your beer doesn’t come out perfectly because of some oddity that must be related to your water. Or you can start out with RO water and build your brewing water from the ground up. Yes this is heavy on the sarcasm, but also heavy on the sincerity of the advice. RO water makes your #1 brewing ingredient consistent.

Response by Ashton Lewis.