Water plays a crucial role in brewing coffee, making up to 98% of the final cup. While most coffee drinkers focus on beans, grind size, and brewing method for their optimal brew, the water used can make or break your coffee experience. Third Wave Water (TWW) is designed to enhance your coffee flavor by optimizing the mineral content in your brewing water. However, the effectiveness of these minerals can depend on starting with what we refer to as "empty water" -- water that is free of minerals, chemicals, and other contaminants.

One of the most common questions we receive is:

"Can I use filtered water with Third Wave Water minerals?"

The truth is that it depends on the filter, but the most common types of filtered water are not going to be good options for using our minerals. Most of the filtered water options found in grocery stores still contain varying amounts of minerals that will interfere with TWW's precise formulas. Let's dive deeper into why filtered water isn't ideal, the science behind mineral interaction, and how to ensure you get the best coffee experience possible.

What is Filtered Water?

Filtered water is water that has passed through some form of filtration system, usually a carbon filter or a resin filter, which is designed to remove contaminants such as chemicals, lead, or organic matter like bacteria. However, filtration does not necessarily mean that the water will be free of minerals.

Common Types of Filtered Water:

• Tap water passed through a Brita®, PUR, or other carbon-based filter
• Grocery store refill stations (e.g., Primo Water)
• Bottled water labeled as "filtered" but not "distilled" or "reverse osmosis"

Why Filtered Water Is not Suitable for TWW:

These types of filtered water will not work well with TWW minerals because they all contain unknown amounts of minerals. Third Wave Water's profiles are specially made to provide the optimal balance of minerals for improving the flavor of your coffee while preventing limescale and corrosion from harming your coffee brewing equipment. Using a starting water with minerals already present can negatively impact your coffee's flavor as well as cause limescale and corrosion to reduce the lifespan of your equipment.

3 Reasons to Avoid Filtered Water

1. Incorrect Mineral Ratios Lead to Unpredictable Coffee Flavor

The minerals present in filtered water can cause your coffee to taste "off." Third Wave Water's profiles are balanced in a way to optimize the correct ratios of the correct minerals to help your coffee taste it's best. Several of TWW's profiles even follow the standards set by the Specialty Coffee Association for improving the flavor of your coffee.

If your water already contains some minerals, then these ratios will become unbalanced leading to bitterness, over-extraction, or unpleasant flavors.

2. Filtered Water Can Contain Hidden Impurities

While filtered water options are free from chemicals like chlorine and organic matter, they are still full of dissolved solids; minerals.

• Carbon-based filters (like Brita®) do not remove minerals
• Many grocery store water refill stations (Primo is the most popular) use reverse osmosis (RO) filtration but reintroduce minerals afterward.

3. Risk of Limescale and Corrosion in Brewing Equipment

Because filtered water still contains minerals after filtration, the risk of limescale and corrosion is not mitigated at all. Limescale, caused by temporary hardness (primarily calcium carbonate, or CaCO3) can clog pipes, degrade performance, and reduce the efficiency of heating elements. If the water contains chlorides, it can cause corrosion in espresso machine boilers.

By starting with empty water, you can rest assured that the minerals present will protect your equipment and help reduce the maintenance required in your machines.

✅ Best forms of Empty Water:

• Distilled Water: Completely purified through evaporation and condensation, leaving zero dissolved solids.
• Reverse Osmosis (RO) Water: Removes all minerals. Be sure no minerals are added back in!
• ZeroWater® Filters: These work similar to a reverse osmosis filtration system, leaving zero total dissolved solids (TDS) in the water.
• Deionized Water: Stripped of all ions, including minerals.

❌ Water to Avoid with Third Wave Water:

• Filtered Water: Water from a PUR, Brita®, or Primo refill station.
• Spring Water: Contains naturally occurring minerals in varying amounts.
• "Purified" or "Drinking" Water: These often contain minerals added back in for taste.

💡Pro Tip: If the water bottle or gallon jug label says "minerals added for taste," it will not be a good choice for Third Wave Water

What About Home Filtration Systems?

Many coffee lovers use home filtration systems for their coffee brewing water, but not all of them are ideal for using with Third Wave Water minerals.

Brita® or PUR Filters: ❌Not Recommended

• These filters remove chemicals (like chlorine and chloramine) and organic matter but do not remove any minerals from your water

Reverse Osmosis (RO) System: ✅ Recommended

• As long as your RO system does not add in minerals after filtration, this is a great option!

ZeroWater® Filters: ✅ Recommended

• Removes all minerals, chemicals, and organics, leaving behind a great form of "empty water"

Stick to “Empty Water” for the Best Experience

Filtered watermight seem like a good choice for coffee, but it’s not the best option for your coffee, especially when using Third Wave Water. The minerals left behind in filtered water can interfere with the precise balance that TWW provides, leading to unpredictable coffee flavor and damage to coffee equipment.

By starting withempty water (Distilled, RO, or ZeroWater®), Third Wave Wateroptimizes your water to create a better experience for your coffee, enhancing flavor, improving consistency, and protecting your brewing equipment.

So next time you’re at the store, skip the filtered water and grab a gallon of distilled instead. Your coffee will thank you. ☕