don't use distilled water in a coffee maker

I learned this one the hard way, but fortunately I didn't wreck my coffee maker.

One would think that using distilled water would be better than tap for brewing coffee, right? That's what I thought. I was wrong.

While I do grind my own coffee beans, I'm not exactly what you'd call a coffee snob since I just buy the cheap whole bean stuff. I'm mentioning this for a reason. A few weeks back, I was in the supermarket and noticed some mid-grade coffee had been discounted. It was cheaper than what I regularly buy, so I said okay, I'll try this stuff.

After getting it back to the house, I ground some of the beans and brewed a cup. It did not taste that good, so I threw it out. At the time, I had a jug of distilled water, so I said screw it, let's try brewing this with the distilled and made another cup. The coffee then tasted better. Not great, but better. Then I said to myself okay, this coffee has been bought, I have some distilled water, and I'll just make coffee this way until I run out.

Not smart.

Here are the three reasons why distilled water is bad for brewing coffee with:

Distilled water is by its very nature tasteless. This is fine for cooking, bathing and of course drinking straight, but not-so much for brewing. Water with some mineral content in it does make for better tasting coffee. Some coffee snobs call that mineral content "notes" in the flavor. Take out the minerals and those notes are gone.

Distilled water can literally mess up the coffee brewing process. When using distilled water, this can cause coffee grounds to swell more, which in turn slows the water flow. What's the result of that? Bitterness from the water not getting through the grounds fast enough.

Distilled water can actually damage a coffee maker. When the water doesn't get through fast enough, the coffee maker works harder to brew. If that happens enough times, you end up with a dead coffee maker.

So what's the best kind of water for brewing coffee with?

Tap or filtered tap. And I suppose water labeled as "spring water" counts too as that has mineral content in it.

Ultra coffee snobs and professional coffee people condition the water used to a very specific ppm (parts-per-million) for "optimum" balance of minerals that brings out the best flavor...

...and I am absolutely not going to do that. All I know is "distilled bad, mineral good" for brewing coffee.

What I learned is that the fact that mid-tier coffee I acquired tasted slightly better using distilled water means it was bad coffee out of the gate. Decent coffee will taste correct with tap or filtered tap water. If it doesn't, that either means you just don't like it, or the coffee is outright bad. And that may be exactly what happened in my situation. That coffee must have been on sale for a reason.

I'm back to my old whole bean coffee and using tap water to brew with. Every coffee maker agrees with it, and the end result is that the coffee tastes good, just how I like it. I won't be swayed by on-sale stuff again, and just stick with what I know works.

Published 2025 Apr 1