How to make the Best Coffee Water: Water Treatment Techniques

In a previous article; Beyond the Bean: What Makes the Best Coffee Water,  we discussed the factors that can affect the taste and odor in water that get in the way from achieving the perfect cup of coffee. Here we will discuss the appropriate treatment techniques to achieving the best coffee water. Due to the many factors that can affect the taste and quality of water, it is important to know the current state of your water supply. We suggest getting a sample of your water tested. This will allow you to create the best treatment plan for your water. International Filter offers free basic water testing for businesses. Most water quality contaminants that can affect taste and odor can be identified by our in-house testing.

Getting your water tested is very important as the factors that affect water quality can vary across geographies. Mineral composition and organic by-products can differ from aquifer to aquifer and lake to lake. Once we have a better understanding of the quality of your water, we can begin developing a treatment plan for your business. Regardless of the results of your water test, there is one water treatment system that will always be necessary — that is carbon filtration.

Carbon Filtration for Coffee Brewing Applications

Carbon filtration utilizes a media called activated carbon. Activated carbon is created by applying heat, pressure, and gas to various materials in the absence of oxygen. These materials can include coconut shells, wood, lignite, and various grades of coal. The material used to create the activated carbon affects which types of contaminants it is most effective at removing.

How Does Activated Carbon Work

Activated carbon is produced to have a network of pores throughout. This porosity results in an enormous amount of surface area. This high surface area allows activated carbon to remove contaminants through a process called adsorption. Adsorption is defined as the adhesion of atoms, ions or molecules from a gas or liquid to a surface. As we discussed in the last section, various forms of activated carbon exist. Each type of activated carbon contains a different sizing and volume of micro porosity. This plays an important role in determining what kinds of contaminants it will be most effective at removing. Some contaminants, like chlorine , are comprised of a long chain of molecules. These are best removed by an activated carbon that contains a medium to large pore structure, like bituminous. Other molecules like , are comprised of a short chain of molecules, and are more effectively removed by an activated carbon that contains a small pore structure like those that produce color. A mismatch between the contaminants molecule chain and the activated carbons pore sizing, can result in the contaminant not being locked in place, and being dislodged as water passes over it, returning the contaminant to your water. The most common approach to using activated carbon when the contaminant is unknown, or price is the primary factor, is to use a middle of the road approach. A medium pore-sized activated carbon is often used because it allows you to remove a broad range of contaminants, often with an acceptable rate of removal. By having your water tested, you will know the exact contaminants present in your water, allowing you to utilize the most effective carbon for solving your water quality issue.

Why Do I Need Carbon Filtration?

There are some contaminants that will always be present in your water supply that can affect taste and odor, and result in coffee that is not ideal. These contaminants are chlorine and chloramines. These chemicals are introduced by city municipalites to protect against bacteria, algae, cysts, and viruses. While we all enjoy the benefits of adding these chemicals to our water, they will get in the way of producing the best coffee; therefore, they will need to be removed prior to brewing your coffee. The most effective media at removing chlorine and chloramines is activated carbon.

Reverse Osmosis in Coffee Brewing Applications

Now that the easy stuff is out of the way, let us discuss the role that reverse osmosis plays in producing the best coffee water. Depending on the results of your water test, it may become apparent that more advanced treatment options are required. Reverse osmosis will be your best tool for addressing the majority of these issues.

What Is Reverse Osmosis?

Reverse osmosis (RO) uses a semi-permeable membrane to remove contaminants from water. Water pressure pushes incoming water through a special membrane to remove a large percentage of impurities. The process of reverse osmosis is achieved with a Reverse Osmosis or RO System. These systems utilize multiple stages to create near pure water, giving your coffee the best opportunity to meet its full potential. Reverse osmosis has the ability to remove minerals, total dissolved solids, bacteria, viruses, iron, heavy metals, and many more contaminants. For a full list of contaminants removed by reverse osmosis see our Reverse Osmosis Rejection Chart.

How Does Reverse Osmosis Work?

Reverse osmosis systems are most easily understood by breaking the system down into its various stages. This will help you understand the role of each stage and how it assists in making the best coffee water.

• Stage 1 Pre-Filtration: The pre-filter, or sediment filter on a reverse osmosis (RO) system is designed to remove large particles from incoming water to protect the further stages from being exhausted too quickly. Without a pre-filter the carbon filters and membrane would become plugged with fine particles, resulting in reduced water flow and efficiency, and inevitably no output.
• Stage 2, 3 & 5 Carbon Filtration: We discussed the role carbon plays in removing carbon at the beginning of this article. In addition to the various benefits we discussed, carbon filtration plays an even more important role in a reverse osmosis system. The semi-permeable membrane we discussed are vulnerable to chlorine and chloramines. These chemicals introduced by your city water supply will quickly destroy your membrane. Therefore, carbon filtration is required to remove chlorine and chloramines prior to the water coming into contact with the membrane. Typically two carbon filters will be placed before the membrane. The first carbon filter removes up to 99% of chlorine and chloramines, and the second carbon filter removes the majority of the trace chlorine and acts as a backup in case the first filter becomes exhausted. In comparison to a membrane, carbon filters are cheap, so it is always the most cost effective practice to have adequate carbon filtration. The third carbon filter (stage 5) acts to remove taste, and any residual particles that can slowly build up in the water storage tank, ensuring you have great tasting water with an extremely clear appearance.
• Stage 4 Semi-Permeable Membrane: We discussed the role that a semi-permeable membrane plays in the previous section. These membranes use an ultra-purification technique called reverse osmosis. Incoming water builds up pressure behind the membrane, forcing water through its multiple layers of wrapped membrane. The tight layers of the membrane allow water molecules to pass through, but restrict passage to other molecules, such as those that make up dissolved minerals, chemicals and organic matter. Semi-permeable membranes are rated on production and efficiency. Production is typically measured by gallons per day. It will need to be determined how much water you are using each day to adequately size the system for your business.
• Storage Tank: Due to the low production rates achieved by reverse osmosis a storage tank will be required to house purified water. This will allow for the volume and pressure required to provide instantaneous access to water in enough quantities for your daily activities. Storage tanks come in a wide range of sizes to fit your unique needs.
• Optional Components: Many additional stages and components can be added to a reverse osmosis system to provide a better experience for employees and customers. Pressure pumps are available for scenarios where low water pressure exist or increased flow at the tap is desired. Mixing valves that blend reverse osmosis and filtered water will be your best bet at achieving the perfect balance of TDS and mineral content for your coffee. Automatic TDS meters will be a convenient solution for knowing when it is time to maintain your system and replace filters.

Why Do I Need Reverse Osmosis for Brewing Coffee?

Reverse osmosis is the only economical way of removing a wide range of contaminants down to an acceptable level for coffee production. By removing nearly all mineral content, heavy metals, chemicals, and organic molecules, you have a clean slate with which to build the best water for your coffee making application; however, using solely purified water will result in coffee that tastes flat. There is still work to be done to bring your water into the ideal parameters for coffee.

Combining Water Treatment Techniques to Achieve a Perfect Blend

Now that nearly all impurities are removed from your water, we will have to reintroduce some impurities back into the water. Some mineral content and TDS is needed to add balance and flavor to the water so that your coffee does not taste flat. Minerals such as salt, magnesium, and potassium impart flavors into water that are beneficial to the overall flavor of the brew. Commercial reverse osmosis systems can be equipped with a valve that can blend filtered water with the purified water produced by the reverse osmosis system. By blending in filtered water, you can still ensure that chlorine, chloramines, and organics are not present in the water to negatively affect taste and odor, while also enabling introduction of beneficial minerals and TDS into the water.

Perfect Coffee Water at Last

We have now covered the fundamentals of producing the best water for coffee. By following these guidelines, you can achieve consistent quality cup after cup. While it seems there are many factors to consider and parameters to control, remember, you are not alone. International Filter can assist you with free water testing and a free consultation to help guide you in the right direction. Give us a call and start brewing the best coffee in your area today!