Coffee And Water Woes: The Mysterious Case of the Metallic Cucumber

I've had a rough time brewing coffee at home over the past couple months - and I just figured out why.
metallic cucumber
✍ Written by: Garrett Oden
📅 Published: July 27, 2023
🗃 Filed under: BREWING | EQUIPMENT

Everyone has off days when it comes to brewing coffee.

You grind incorrectly. You mis-weigh the water. You forget to start the timer.

There are a number of reasons a person may accidentally harm his cup of coffee every once in a while.

But what about off months?

Those are the result of poor coffee, bad habits, or malfunctioning equipment.

For about two months, I’ve been experiencing relatively poor cup quality when I brew at home. There was a flavor element that was entering my final cup, but I couldn’t nail what it was – until now.

At first, I thought it was my use of a newer brewing method: the notNeutral Gino. So I spent hours working on a refined recipe. After experiencing a poor V60 and realizing it wasn’t the Gino’s fault, I thought it might be the water quality.

Thus, I tried four different water bottles to remedy my problem. I even did quite a bit of research on my local water sources. The research was very insightful, but alas, the mystery of the poor coffee endured.

I side by side tested water, coffee, brewing methods, recipes, and grind sizes. Finally, I was able to identify the flavor that was entering my cup time and time again over the last couple of months.

Metallic cucumber.

This led me to one final experiment.

Yesterday I put half an Ozarka water bottle in a cup, and the other half in my Bonavita Variable Temperature Kettle and set it to 205 degrees Fahrenheit.

When it was finished boiling, I poured it into a second cup. I let both cups of water sit for nearly five hours while waiting for them to reach room temperature. Then the moment of truth arrived.

metallic cucumber

The water straight from the bottle was smooth and pleasant. The boiled water tasted like metallic cucumber. Then it all made sense. I bought the Bonavita kettle on August 4th, nearly two months ago, and it has been tainting the flavor of my coffees ever since.

What a disrespect to the many coffees I drank over the last seven weeks!

I’ve contacted Bonavita and informed them of the flavor taint and the appearance of potential rust spots inside the kettle.

For now I’ll be going back to my electric kettle. I’ll let you know how Bonavita responds.

Lesson Learned: When brewing troubles arise, check the equipment before plowing through and wasting beans.

UPDATE October 8th: Despite receiving only an automated message from Bonavita, they came through in a timely manner. A new kettle is now in my hands! Back to crazy experiments.

Garrett Oden

Garrett Oden

Coffee Industry Writer

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