Can You Use Tap Water To Make Coffee At Home?

Can You Use Your Tap Water For Coffee?

So many of us prefer to get our coffee fix at home, and rightly so. Not everyone can afford Starbucks everyday. But the most frustrating thing with making coffee at home is that it never tastes as good as Starbucks.

The key differentiator between your coffee at home and the one you buy is just 1 thing- plain old water. So yes, you can easily use tap water to make a GREAT cup of coffee at home, as long you keep in mind certain things about your water itself.

Firstly, water makes up about 96% of a cup of coffee and is the most important ingredient. It is of utmost importance that your water have just the right composition of minerals, otherwise you’ll end up with something that tastes like coffee, but not quite as good as you want it to be.

The thing about Starbucks and other coffee chains is that they maintain the same standard tastes across the country because they use professional filtration techniques to ensure that all outlets use the same type of water. Which in turn means they can use they same type of beans and so, they have a scalable business.

So how can you ensure that you get a great cup of coffee at home?

By looking at your tap water and checking what it’s composition is like. In this article, I’ve laid out, step by step, everything you need to know about having the best water for making coffee.

A word of warning though: You will still have to do a bit of experimentation to figure out the best tasting coffee for you. Use this article to arm yourself with the knowledge you’ll need to experiment. Once you’ve figured it out, I’m confident you’ll be able to make great tasting coffee every single day at home.

What is the best water for your coffee machine?

One of the biggest Non-profit trade organizations in the coffee industry, the Specialty Coffee Association of America(SCAA) laid out a few guidelines in 2013 on the best water quality for coffee brewing. They are a bit technical, so bear with me- I’ll break them down, one by one.

According to SCAA guidelines, the best water for coffee has:

  1. No odors
  2. Clear color
  3. No chlorine content
  4. Total Dissolved Salts(TDS) in the range of 75-250 mg/L. Optimum- 150 mg/L
  5. Calcium Hardness in the range of 17 mg/L to 85 mg/L
  6. pH should be between 6.5 and 7.5
  7. Total alkalinity near 40 mg/L
  8. Sodium levels near 10 mg/L

Here’s the break-down of the guidelines:

Odor, Water Clarity and Chlorine:

It’s pretty self explanatory why water shouldn’t contain odors and color. They are two big indicators that water is impure. However, in a lot of places, such as the US and Europe, people drink chlorinated water straight from the tap. While chlorine is necessary for purifying water, it also imparts a distinct taste and odor to water that tends to spoil the taste of coffee.

Also, according to watertechonline, chlorine, being an oxidative agent, tends to oxidize the oils and aromatics in coffee beans, imparting an earthy or moldy tone to the coffee. I recommend buying a simple water pitcher filter containing activated carbon for removing chlorine, such as this one on Amazon.

Total Dissolved Salts(TDS)

Measuring Total Dissolved Salts(TDS) is a way to know the concentration of minerals in your water. It is important to know 2 things regarding TDS:

  1. What is the concentration of the dissolved salts in your water?
  2. What is the composition of these salts?

Importance of Knowing The TDS Concentration:

The flavor in coffee beans doesn’t just infuse into water on it’s own – it needs the right ingredients. These ‘right’ ingredients are minerals. You see, minerals are needed, in the right quantities, to extract the coffee flavor.

And you need the right type of minerals too. For instance, according to Baristainstitute.com Magnesium is slightly better at extracting the coffee flavor than Calcium. But that’s more advanced stuff than you should worry about.

For now, just keep it in mind that your water should have the TDS concentration in the range 75-250 mg/L, with an optimum mineral concentration at around 150 mg/L. You can get a TDS meter, such as this one on Amazon for this purpose.

Importance of Knowing the TDS Composition:

Keep in mind that the SCAA guidelines do not specify what should be the composition of the Total Dissolved salts in water. Generally though, commonly found minerals in water are Calcium, Iron, Manganese and Magnesium. Some, such as lead or nitrates, can be downright dangerous, even at very small concentrations.(You can read more about this topic here)

If you’re unsure about the composition of the dissolved salts in your water, I recommend getting a home water testing kit, such as this one on Amazon.

If your water is in the right TDS concentration range, that’s great. If it isn’t or if you find that it contains some dangerous contaminants such as lead, nitrates or mercury, I recommend investing in a RO filter for your home. It’s the only commercially available method to reduce TDS of water at home. Apart from ensuring that you get the best water for your coffee, getting an RO filter has another advantage:

It’ll increase the life of your coffee machine. If your water is hard- i.e: contains an excess of calcium and magnesium salts- it’ll leave scaly white deposits which clogs the coffee machine from the inside.

They are easily available on Amazon as well. If you’d like to know more about this topic you can read this article I wrote: How to decrease TDS in water at home?

Why I Wouldn’t Worry About The Rest of The SCAA Guidelines:

The rest of the guidelines (#5 till #8) talk about sodium and calcium concentrations, alkalinity and pH. These are all things that are mostly controlled by the TDS levels(don’t forget that sodium and calcium are dissolved salts as well) and will take care of themselves, once the TDS levels are brought into the right range.

The crux of the SCAA recommendations, therefore is:

  1.     Get your TDS in the correct range, as specified
  2.     Ensure no odors, that water is clear ad contains no chlorine.

As a home brewer, I believe doing just these two things will put you miles ahead of the average person. The rest of the recommendations are nice to haves. If you’re still interested, here’s a brief on how they affect the taste of your coffee.

How pH of water affects coffee taste:

  •       pH is a metric for knowing how acidic or basic a particular material is. It works on a scale of 0-14, where 0 is the most acidic, 7 is neutral and 14 is the most basic(or alkaline).
  •       SCAA recommends that your water be in the neutral range so as to not tilt the balance of flavor to either the acidic end(vinegary) or alkaline end(flat, earthy).

How Sodium affects taste of coffee:

Sodium content is usually a little high in homes where a water softener is used. If in excess, it tends to impart a salty taste to water, and is dangerous for people who are on a low sodium diet.

How Calcium affects the taste of coffee:

Calcium and Magnesium are two minerals usually found in most water supplies. They give water a pleasant taste, and are responsible for extracting the flavor from coffee beans. In excess however, calcium will just give a dry, moldy flavor to the brew.

How Alkalinity affects the taste of coffee:

Alkalinity is usually dependent on the concentration of carbonated and bicarbonates in water, which are negatively charged and hence, are basic. They counteract the weakly acidic coffee beans. In the right composition, they ensure the taste isn’t too strong or vinegary in taste. If in excess, they impart a flat taste to the coffee.

They are usually present in water in the form of calcium and/or magnesium carbonate salts, which is also known as temporary hardness in water.

Final Tip On Using Your Tap Water For Brewing Coffee

I found a really practical suggestion online regarding this.

After you’ve figured out the TDS of your water and found out how hard it is, contact a local coffee brewery-they usually know the type of coffee beans that would be best suited as they test their brews in local waters too. If you’re unable to do this, the general rule of thumb is: 

If your water is hard, use a subtly roasted batch of coffee beans. If the TDS levels in your water are low, use a strong roasted batch because the extraction capability of the water would be that much lesser.

Conclusion

Anyone can brew a great cup of coffee at home. You don’t need to buy bottled water for your coffee machines at home like some people do. That’s just not sustainable. Just use your tap water.

You may need to filter it for chlorine and reduce it’s TDS with an RO filter, but these are long term investments- not just for your coffee, but for your health as well. `

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