Eau de vie, Voda, Uisce beatha — the names of our favorite spirits literally mean “Water of Life.” Water and the history of spirits are closely interlinked, their mythology tied since the first alchemists began experimenting with distillation more than 1,300 years ago. Water is an integral component of fermentation and the creation of alcohol and is added to most spirits before bottling, so it is a wonder that water doesn’t feature in ingredient stories as often as other raw materials.

Let’s face it, though water may feel commonplace, it is actually a rather weird substance. Its very existence on planet Earth is one of the keys to making life possible, yet water behaves so differently from many other compounds. For instance, have you ever noticed how ice floats in a glass of liquid water? While some may attribute this to tiny air bubbles caught in ice during freezing (drawing the ire of perfectionist bartenders everywhere), that’s not the case. Unlike just about every other substance known, water is slightly less dense in its solid form than it is as a liquid. Water also has the distinction of being the only substance on Earth to exist naturally, somewhere, in all three states — solid, liquid and gas. H2O is also a universal solvent, meaning that it dissolves more substances than any other compound, a property that lends much of the character to the different types of water we know and love; as water dissolves minerals such as calcium, magnesium or sodium, it takes on the characteristics of those minerals.

The flavor of water has been the subject of debate for hundreds of years, with the early consensus being that water is a tasteless, odorless substance that acts only as a vehicle for other flavors. That may be true for absolutely chemically pure water, but even then, water isn’t completely neutral in terms of our sensory experience of it. Recent research points to specific cells in the palates of mammals in particular that can sense water. Studies at the California Institute of Technology in Pasadena have compared the measurable electrical signals in the taste buds of mice while receiving different taste stimuli — sweet, sour and bitter — and have found that the taste buds themselves also sense water, even when no flavor is present. Studies such as these point to our ability to “sense” water and its presence, helping animals to choose this life-sustaining substance over other liquids.

As a universal solvent, water is wonderful at picking up minerals and compounds it comes into contact with. The specific mineral content and flavor profile of a particular water can vary greatly from place to place, providing an interesting terroir that can influence the quality of spirits made with it. Magnesium, for example, can create bitter flavor notes, whereas calcium adds round, creamy characteristics. Measuring the total dissolved solids (TDS) in water can provide a clear idea of the concentration of minerals such as calcium, magnesium and potassium in the water, though it doesn’t differentiate which minerals are present. The exact blend of minerals present and their concentrations are the “ingredients” in the water that give it its unique character, as well as its overall pH.

Brewers know that water chemistry can greatly affect the flavor and mouthfeel of their beers. When it comes to distillation, however, the minerals in fermentation water stay behind in the pot during the distillation process. During mashing though, pH is so greatly affected by the grains selected that pH of the water should only matter insofar as how it contributes to the optimal pH for yeast to remain healthy during fermentation. Municipal water should be filtered to some extent to remove fluoride, chlorine and other additives, as these may have an effect on the resulting distillate if present in sufficient concentration.

More important is a distiller’s proofing-water program. Proofing water can make up as much as 50–60% (or more, in some cases) of the final bottled product, so the flavor and mouthfeel of the chosen water will have a significant impact on the final product. Water sources such as springs, wells and aquifers tend to have higher mineral content and unique flavor profiles that can add a sense of place to bottled spirits. Brands such as Finlandia espouse the flavor of the glacial water they use to cut their spirits to proof, and Suntory values its water sources so deeply that it refers to them as “soul places,” referring to the Japanese concept of a place that is a source of deep spiritual reflection.

Such specific water sources give Suntory’s spirits a sense of place. However some distillers prefer to let their other ingredients tell the story of their spirit or brand, and in those cases, a pure clean flavor profile is desirable in your water. Luckily, various methods exist to treat municipal water to create a clean and neutral profile that doesn’t augment or affect the spirit’s flavor or texture.

Tap Water

Municipal or tap water sources can vary greatly from location to location. Water can come from reservoirs, lakes, large wells or aquifers, but it is usually treated prior to distribution to homes and business to ensure EPA compliance. The EPA doesn’t regulate the pH of tap water, as pH is considered an aesthetic characteristic, but most tap waters measure at a pH around 7.5, or slightly alkaline, a level generally intended to minimize corrosion of plumbing.

The EPA sets legal limits for 90 different contaminants in water, which include microorganisms, radioactive contaminants and some chemicals. Local governments, however, are allowed to establish their own drinking water standards, as long as those standards are at least as stringent as those established by the EPA. Also, water is often treated using fluoride to protect dental health and chlorine to protect against contamination. Distillers should request a water quality report from the local utility annually to determine the concentration of such additives as well as the mineral content of the water. It is also important to note that the pipes the water travels through after treatment can also add flavor to the water. Plastic or PVC pipes can add a fruity, chemical note to water, whereas water flowing through older iron pipes may pick up metallic hints.

Spring Water

Spring water is collected from natural springs, often in mountainous areas where it begins as runoff. The water picks up minerals along the way as it flows through subsurface rocks and soil that give it a unique flavor profile and texture. Spring water is a favorite of many distillers around the world, with some going so far as to purchase exclusive rights to a spring or to have water from a particular spring delivered to the distillery.

Well Water

Well water is groundwater collected from below the surface and usually contains higher levels of minerals. Well water should be tested for contaminants and is most often filtered before use. Well water is collected differently from spring water. Spring water must flow to the surface on its own, whereas wells are often drilled by boring into the water table or aquifers, often hundreds of feet below the ground’s surface. Because well water doesn’t flow to the surface, it collects and concentrates minerals in different ways than spring water.

Volcanic or Alkaline Water

Volcanic or alkaline water is often sourced near minerally rich volcanoes, although it can be artificially produced by adding ionized minerals to raise the pH level. By selectively adding minerals at specific concentrations, water can be modified to emulate the flavor of water that picked up these same elements naturally by flowing through bedrock or into a reservoir. These higher pH waters are said to have a silky, smooth taste. Alkaline waters typically have a pH between 8–9.

Deionized Water

Deionized (DI) water is created by exposing water to ion-exchange resins that are charged to attract the ionized minerals in the water, removing all of the mineral content and creating a water that is “blank.” Minerals such as calcium, potassium and magnesium become positively ionized when in solution with water owing to their extra electrons. During the deionization process, the water is passed through a medium that is negatively charged, causing the positive ions to bond with the medium and be removed from the water. Deionized water is often used in pharmaceutical, medical and biotech applications to provide a base that is chemically pure for creating chemical solutions. DI water can be created from any conventional water source and is very consistent in flavor, but it lacks uniqueness or character. DI water also immediately begins absorbing CO2 as soon as it comes into contact with air, lowering the pH to slightly less than 7 and making it slightly acidic.

Reverse Osmosis

Reverse osmosis (RO) water is produced by forcing water through a semipermeable membrane, which traps larger molecules such as minerals, bacteria and chemical additives. RO water is also very consistent in flavor and provides a clean, characterless additive to spirits. Most RO units contain carbon filters which “polish” the water post-reverse osmosis treatment. RO water has a similar pH to DI water. The downside to using RO systems is that they are very wasteful. RO systems flush-clean their filtration membranes throughout each cycle, so for every gallon of RO water collected, 2–6 gallons of water are flushed away as waste.

Filtration

Of the variety of filtration methods that exist, the most common water filtration medium is activated carbon. Carbon is great for removing chlorine while leaving more of the water’s natural mineral content intact. Activated carbon is a wonderful substance because it is highly absorptive and incredibly porous, with a ton of surface area onto which it can absorb charged compounds — 32,000 sq. ft. per gram, in fact, or more than half an acre per teaspoon. It is also negatively charged, so it can naturally attract positive ions in the form of minerals, and trap them, pulling them out of solution. Carbon is minimally effective, however, at removing fluoride, so heavily treated municipal water sources may require different methods of filtration or purification.

Water sources vary greatly, and like any raw material, a variety of sources should be considered and evaluated using QA procedures such as lab evaluation, TDS measurement, pH measurements and sensory evaluation. When establishing a water program at any distillery, the costs of various water sources can also be a large factor in determining water selection. Most municipalities publish their water quality reports and pricing on their websites, which make this a great place to start. Water quality reports should list the water source, MCL (maximum contaminant level allowable) for a variety of contaminants, as well as the actual level of each possible contaminant. MCLs are set based on the health impacts of each contaminant and don’t take flavor into account, so there is no substitute for sensory analysis when evaluating a municipal source.

If a distiller wishes to install a filtration system, DI, RO and other filtration systems should be evaluated for installation and maintenance costs and the quality of water produced. In some instances, when factoring the cost of municipal water plus filtration costs, unique water sources such as well or spring water become viable and competitively priced options.

Water literally runs through every aspect of the process of crafting distilled spirits. From nourishing the grains, sugarcane or fruit as it grows, to cleaning our tanks and providing cooling to condensers, to providing the final proofing cuts, no ingredient is more present throughout the process of creating high-quality spirits or is more integral to the uniqueness of each product.



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Caley Shoemaker
Caley Shoemaker currently leads operations of The Hangar 1 Distillery as head distiller. A Denver native, Caley got her start in craft-spirits distilling at Stranahan’s Colorado Whiskey where she immersed herself in every aspect of the production process. She’s a self-proclaimed “spirits nerd” fascinated with how fermentation, distillation, ingredient selection and maturation affect the quality and flavor of the final product.