☕ Coffee Journey - Water


Photo by Jacek Dylag on Unsplash

Welcome back to my Coffee Journey. Today we're talking about the fact that coffee consists in 98% water, which is one of the four fundamentals when it comes to coffee preparation: 

  • Proportion (Ratio)
  • Grind
  • Freshness
  • Water

Personally, I would love to add "Time" as the fifth participant, but let's leave this aside. 

Let's start with water

What's the big deal about the water, you may ask? Water is water, right? 

Well, no. 

You may actually ruin your coffee if you are using water that contains chlorine, or smells like iron or sulphur, so please use fresh, cold, filtered water. Cold as opposed to from the hot water storage tank.

Let's talk about the temperature some more. The perfect water temperature for brewing coffee is 195 - 205°F = 90 - 96°C. The higher the temperature of the water, the more quickly extraction will happen. If water is too cool, extraction takes much longer. At a certain point, some compounds simply won't extract. This is why a cold brew takes much longer and has a much more mellow flavor than a hot brew of the same beans. 

Hot coffee will also be more acidic due to the acid levels in the coffee bean's fatty oils. The hot water will break up these oils much quicker, depositing much more acid into the coffee. Much more as in 70% more compared to cold water!

So if you suffer from an upset stomach from drinking coffee, cold brew may be for you. 

I know you didn't sign up for science class when you clicked on this blog post, but allow me one last word about water quality: water hardness. Yes, depending on where you live, you know full well water hardness is a factor in your daily life when it comes to washing your hair, doing laundry, cleaning your surfaces in the kitchen and bathroom or maintaining the appliances in said rooms. 

What does this have to do with coffee though? 

Well - everything! Considering coffee is 98% water, the same coffee will taste totally different if you live, say in New England or Southern California and use unfiltered water.

So if you're interested, check your water hardness with your local utility company and compare it to the recommended standards:

Source: Barista Institute


Treat coffee like any other fresh produce and protect it from oxygen, light, heat and moisture. So please store your precious coffee in an opaque, airtight container at room temperature, and use it within a week (two, if you must) of opening.

I don't know who came up with the idea of storing coffee in the fridge, but it's a bad idea for the following reasons:

When coffee beans were roasted, they lost moisture and started to create sugar through caramelization. Ever since they've been ready and willing to absorb water. in the fridge there is a lot of moisture, which basically starts the process of extracting flavors. Meaning if you use beans or grounds that have bee stored in the fridge, you are basically using stale and partially "brewed" coffee. Plus, since coffee works as a deodorizer it will absorb all the aromas in your fridge. Unless you like roasted chicken flavoured coffee, don't do it. Also don't leave your coffee beans behind in your car. Temperature changes, sunlight and humidity will ruin them. 

When Starbucks' business started to grow, they encountered the following challenge: how to supply all of their stores with fresh-roasted coffee beans without building a roasting plant in every city?

A creative mind - I wish I remembered their name - came up with the concept of FlavorLock bags, which have a one-way valve that allows carbon dioxide released by the beans to escape without allowing flavor-robbing oxygen to get in. Very clever.

Also they are very particular about their standards in making coffee. An espresso shot needs to be used for these lattes and cappuccinos within 10 seconds. Brewed coffee will be replaced every 2 hours. 


Here are some recommendations for grinding:

  • coarse for French press
  • medium for flat bottom drip
  • fine for cone filter
  • extra fine for espresso

If you grind your coffee finer, you'll expose a lot more surface area, which is very useful for  extracting more coffee flavor. But when you change the surface area, you also change the way that the grounds interconnect with each other. So when you tamp them down in your "coffee puck" the finer the pieces are, the better they fit together, and the harder it is for the water to flow through them. This will increase the contact time between the water and the coffee. 

If you can, always grind just before brewing.

Source: James Hoffmann


A general recommendation is to use a 1:16 ratio of coffee and water. Here's a chart with very detailed measurements and ratios for your convenience. Personally I use 10 grams = 1/8 cup or 2 tablespoons of ground coffee for 180 ml = 6 ounces of water, and I use my simplified French press method. It includes a spouty cup and a sieve, just the right size for one person. I only use the French press when several people are having coffee. 

I can't wrap this up without telling you why I consider 


 just as important as the other factors. Here goes:

One not so fine day I was preparing a French press, and I accidentally put 4 hours (instead of 4 minutes) on my timer. My inner clock told me at some point it might be time. The coffee had been brewing for 5 minutes, and it tasted terrible. Nothing like a little mishap to learn life lessons!! 

Are these explanations helpful to you? Will you look at storing, grinding and preparing your coffee differently from now on?


  1. We do store coffee in air tight containers at room temperature and not in the fridge ! Tahts a good tip explaining well about storage..lol at the chicken coffee😅 we boil water and mix coffee powder, or we make Indian filter coffee ( not sure if u heard) - that's a bit here..that flavor lock bag idea is so cool!

    Hav a grt day

    Dropping by from a to z "The Pensive"

  2. WATER is definitely key and it is absolutely so true. I can tell you from experience when purchasing a STARBUCKS TALL PIKE in Saco, Maine compared to a STARBUCKS TALL PIKE in Lexington, South Carolina the taste is totally different. I love a good tall black PIKE, but the water is KEY to making it right. Tam, I am definitely going to try to stay in touch after this A2Z challenge is over. You motivate me and keep me wanting to write and I appreciate that.


  3. Very informative post, specifically about water. Never knew about most of them, except a little about water hardness.

  4. Oh, I know how important water can be. I might not drink coffee, but how it's brewed and made and such is still fascinating.

  5. Another interesting blog! This can go for anything we use water for, since I'm a big water drinker I need to have good tasting water.

  6. My husband is the coffee drinker at our house and sometimes when we are out and about and he gets a cup of coffee elsewhere, it kills his stomach. I need to tell him this, "So if you suffer from an upset stomach from drinking coffee, cold brew may be for you."

  7. Very interesting article and informative. I lived in California for most of my life and never much thought about the hard water we had until I traveled. But even then I never took the time or noticed that my tea (not really a coffee drinker) did taste different. I really noticed it after moving her to CO. It takes so much better. :) Just wanted to share that. Thanks for sharing your post.

  8. Tamara, WOW. I learned a lot today, and I thought I knew a lot about coffee before! Thanks so much! I want to figure out how to do cold brew at home. Have you already written about it?

  9. Water quality is always the key to great drinks- coffee, pop, whatever.

  10. Thankfully I live in a part of the US known for it's particularly clean and fresh water.
    This is a great theme, I'll need to go back and read more!

    Tim Brannan
    The Other Side | A to Z of Conspiracy Theories

  11. OK. I am totally amazed at all the different details about coffee! It truly is a science!

  12. Never knew about such high water content in coffee :-)
    All my A to Z Challenge blogposts)


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