How to Remineralize RO Water for Coffee Brewing
Written by: Gene Fitzgerald // Last Updated: Jun 30, 2023
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A cup of coffee in the morning is almost a sacred ritual and one of life’s little joys. So, you want your cup of joe to be as best as it can be.
If you use reverse osmosis water to make your coffee, this may mean adding a remineralization component to ensure your water has the right chemistry to extract all the goodness from your coffee beans.
How can you do this? We have a few suggestions.
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Key Takeaways
Remineralizing RO water to brew coffee can be done in several different ways:
- Get an RO system that has a remineralization filter.
- Add a remineralization filter to your existing RO system.
- Remineralize your RO water by hand with drops or powder.
How to Remineralize RO Water for Coffee Brewing
So, how to remineralize RO water for coffee? You can remineralize RO water in the following ways:
Get an RO System That Features Remineralization
If you are utilizing reverse osmosis water for brewing coffee, it is best to get a system that incorporates a remineralization step in the filtration process. This step will be able to put back some of the essential minerals, like calcium and magnesium, that get filtered out when using RO water, which are needed to properly extract the flavor from your coffee.
And the best thing is, the remineralization is fully automated and you don’t have to worry about it!
Add a Remineralization Filter to Your Existing Reverse Osmosis System
If you already have a reverse osmosis system but no remineralization filter, you may be able to add one – this works for most under sink RO system, for example.
Simply add the filter as the final step before your water is dispensed from the faucet.
Add Minerals By Hand
The downside to using a remineralization filter is that you don’t have much control over the type of minerals or the amount of minerals that are re-added to the water. So, you could add the minerals by hand using a mineral drops solution or a powder. This gives you more control over the type and amount of minerals you add to your water, but it’s an extra step in your brewing process, and it can also be complicated and time-consuming.
What Minerals to Use and How Much?
The two most essential minerals to re-add to your RO water are calcium and magnesium carbonates. In the right quantities, these minerals help extract the most flavor from your coffee beans during the brewing process.
Calcium Carbonate
The Specialty Coffee Association (SCA) recommends water with a calcium carbonate hardness of 50 to 175 ppm.
Magnesium Carbonate
The SCA does not provide a range for magnesium carbonate. But magnesium plays a minor role anyway. If you do add both calcium and magnesium carbonate to your coffee water, a combined hardness of 50 to 175 pp should be ideal.
Why Remineralize RO Water for Coffee?
Remineralizing RO water for your coffee is important as both TDS and water hardness play crucial roles in the coffee brewing process, influencing extraction rates and the taste of the coffee.
High TDS levels can lead to over-extraction, producing an excessively bitter or sour cup of coffee. Conversely, low TDS levels can cause under-extraction, producing coffee with insufficient body and flavor. Water hardness also impacts the extraction rate, with overly hard water causing over-extraction and excessively soft water leading to under-extraction.
Remineralizing your RO water can prevent this from happening, plus help protect your coffee brewing equipment from corrosion due to the solvent nature of pure water.
SCA Water Standards
The SCA has particular standards for the ideal water conditions for brewing coffee, which are as follows:
- Odor: Clean/Fresh, Odor free
- Total Chlorine: 0 mg/L
- Calcium Hardness: 50-175 ppm
- Total Alkalinity: 40 ppm
- pH: 7.0 (Acceptable Range: 6-8)
Further Reading:
The Pros and Cons of Using Plain RO Water for Coffee
Pros of RO Water in Coffee Brewing
- Chlorine Elimination: Reverse osmosis systems remove chlorine, preventing off-flavors in coffee and eliminating other contaminants affecting taste and smell.
- Hazardous Contaminant Removal: RO systems filter out heavy metals, organic compounds, and bacteria, ensuring a cleaner, fresher, and safer cup of coffee.
- Stable Flavor: With minimal TDS, RO water offers a consistent coffee experience even if the municipal water supply’s taste and smell change.
- No Scaling: Not containing minerals, RO water won’t cause scaling in your coffee maker.
Cons of RO Water in Coffee Brewing
- Loss of Helpful Minerals: The filtration process removes essential minerals like calcium, magnesium, and sodium, potentially resulting in flat or flavorless coffee.
- Higher Expenses: RO systems can be costly, making them an impractical investment for some, contributing to increased water bills and maintenance costs.
- More Time-Consuming: Brewing coffee with RO water takes longer, mainly if dealing with an empty storage tank.
- Corrosion: RO water is highly pure and slightly acidic. As such, it’s more corrosive.
If you have any questions about how to remineralize RO water for coffee please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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