Water is the number one subject people ask about. Water is the solvent that brings for the oil from the grounds. Without water, there’s no coffee. Learning about water and how to view it helped me enormously to brew better coffee. As in most things coffee, there are lots myths surrounding water. I want this to be short and sweet. Here’s my quick opinionated practical guide to brew great coffee.
Hard Water
“Hard water won’t extract because it’s already too full of minerals.”I hear it all the time. Don’t think of water as absorbing coffee oils. Think salad dressing. Oil and water don’t mix. Think of heated water being a solvent that removes coffee oil from the grounds and they get mixed into the hot water, making the beverage known as coffee. Also, when water is heated the minerals go into suspension. They are virtually unimportant during brewing. What minerals do is add taste. The reason not to use highly mineralized water is they risk adding a flavor that competes with or clashes with your coffee flavor. If that’s not reason enough, hard water suspended during heating, cools and hardens on the insides of your coffeemaker’s plumbing. It doesn’t take much to clog your coffeemaker’s arteries and interfere with the flow. This causes everything from substandard brewing temperatures, to slowing down brewing to simply halting the process. A coffeemaker manufacturer’s repairman once told me the majority of their service was simply calcium-choked coffeemakers.
If you have highly mineralized water, you should do the following: Drink some. If it tastes good, you can brew coffee with it. If the water doesn’t taste good, you shouldn’t brew with it because it will flavor your coffee, almost always it will taste bad. For bad tasting water use bottled water. For very hard water, you can choose. If you are willing to routinely be running vinegar or Urnex (a good coffeemaker cleaner) through your machine, and use fresh water (better still distilled or low-mineral bottled water) to rinse afterwards, you can continue to use hard water. But consider if your water is hard enough, you won’t save much by just switching to bottled water, compared to buying vinegar, coffeemaker cleaner and bottled water to rinse the machines.
Bottled Water
If you use bottled water, check to see that it is low enough in minerals to make a difference. Usually it is lower simply because most bottled water manufacturers do some filtration to make their products consistent… but not always. Some bottled waters are full of minerals and not even any softer (meaning lower in mineral content) than the hardest tap water. The most reliable waters for brewing coffee are so-called drinking water, which are usually highly filtered municipal waters. Most often, they are treated with reverse osmosis filtration, which all but eliminates minerals. Then, the water bottler adds some particles in controlled amounts, just enough to add ‘normal’ flavor – water with no minerals can taste ‘flat’. There are some excellent good-tasting bottled waters, both low in minerals and with good taste that are not r/o filtered, but they take a little patience to find.
Softened Water
Under no circumstances should you use softened water, meaning water that’s been treated with a home water softener. Actually, there is an exception – espresso machines sometimes benefit from softened water, but these are dedicated machines and it’s a special case. I’m still not certain I fully approve of it, but at least it qualifies as a possibility – with espresso. This is not true using drip, vacuum or press pots. Softened water is especially problematic with automatic drip machines, where softened water and ground coffee can combine to make gelatinous goo that will become stuck in your brew basket.
Softened water is virtually undrinkable anyway due to its elevated sodium content. I anticipate the question of alternate softening methods. To be honest, I don’t know, nor do I know if it’s been researched by anyone. I’m eager to learn if any tests have been done.
So, there are the coffee basics you need to brew great coffee minus the myths.
Excellent post about water and coffee. Great points about differences between hard water, bottled water and softened water. Very practical tips for making a great cup of coffee. Thank you for sharing your insights and expertise.
I appreciate your kind comments. It surprises me how much effort goes into making coffee and suddenly a tap goes on and all our other detailed work is affected by a variable subject to wide variances.
I have well water that goes through 3 filters plus a UV light. It makes delicious coffee but I notice in my tea pot white flakes so I clean with coffee pot cleaner as soon as I see it,
What about alkiline vs acid water?
I prefer slightly acidic water for brewing coffee, but I have no hard evidence just personal experience and observation.
We used AquaFina in our last dripper which made it clog monthly.
So we bought a new dripper and only been running Ice Mountain for 3 months which now it finally is clogged. Ice Mountain runs better than AquaFina. Noted.
Hi Demi,
The only reason I can imagine this would be if AquaFina is unfiltered and/or extremely hard (full of minerals) compared to Ice Mountain, which is presumably demineralized before packaging. Then, it’s very possible.
We have just moved into a home with well water, which is naturally soft water here. I do not want to deal with bottled water, (limited space) and wondered if I grind my coffee differently for drip, will it help with the taste (seems weak to me)? I have heard certain waters sit on various grinds differently…
Hi KP,
I also live in a home that uses well water. I’m glad yours is naturally soft, which is generally favorable for coffee. Yes, water definitely affects the brewing results, in two ways. First, hardness impedes and softness facilitates brewing. Second, in hard water, the minerals can offer competing flavors as minerals have tastes of their own. pH affects the taste as well. While there are some basic standards, such as medium-hard water being recommended, my opinion is that it is a case-by-case situation, as the subtleties of flavor and aroma are complex; coffee is a delicate product. I’m a bit surprised by one thing you wrote: that soft water appears to make weak coffee in your kitchen. That goes against most accepted lore. I’d buy a gallon or bottled water just to compare. Obviously, the most direct way to increase strength is to grind finer, and if you just want to try a notch finer, okay. I assume you’re already using enough coffee, but increasing the grounds to water ratio makes it stronger.
Let us know it goes.
Warmly,
Kevin
Nice article. I have a water distiller and have used distilled water to make coffee in a drip machine. I like having the “pure” flavor of the coffee without the distraction of the mineral flavor. Granted, when I say I like it, I’m guessing it’s mostly a placebo effect because I doubt I could tell the difference in a blind taste test.
The real benefit is that my coffeemaker doesn’t need to be cleaned, probably ever, but certainly hardly ever.
Thank you, Royce. I suspect you could taste the difference. However, most home distillers leave just enough mineral content so as fall short of absolute zero minerals. As long as it tastes good to you, that’s what’s important. I used to have a Sears R/O unit and I made some outstanding coffee using it. As far as I’m concerned water is still a huge subject we haven’t really mastered. At least I know I haven’t.
None of the comments above mentioned how critical the brewing temperature is. I have never noticed any difference between hard and soft water. Only our hot water is softened. Surely the “ideal” brewing temp is difficult to reach in the average home. Isn’t it?
Hi Bill,
I totally agree with the importance of brewing temperature, although there are legitimate arguments about what that temperature should be. Every review here has published brewing temperatures, which I’d included since my Coffee Companion print days starting in the early 1990s. I think the biggest challenge most folks have at home is their automatic drip brewer’s ability to brew at the right temperature along with the equally important ability to expose the grounds to this perfect temperature water for the right amount of time to extract the best flavors and not the bitter ones. This article was specifically about water quality. This can regionally vary quite a bit and, while it might be subtler than brewing temperature variance, the softness of your water and its pH can be significant factors on how it tastes, as well as affect your brewer’s performance.
Good point, though. Thanks for contributing.
Warmly,
Kevin
Completely disagree with your statement regarding the use of sofetened water. I have a water sofetner and use my tap water for my, Kurig, French Press, and drip coffee maker and I never have any issues with taste or the functionality of the coffee makers.
Hi Steve,
Never a problem with you disagreeing with me. I welcome your experiences. It’s been years since I had softened water. To be sure, the most reported issues are with larger batch automatic drip. I’m sure a single-cup would not be affected. Meanwhile, if it tastes to your liking, that’s what matters.
Warm regards,
Kevin
I just moved and have a Bunn, I’m using the same filters and coffee, only the water has changed. My coffee grounds are running over my filter no matter what I do. The water here is much softer but does not have a softner. So from what I’m reading my problem most likely is in the water.? I do note the change in taste. I’ll have to test out some bottled water to see if this helps. Suggestions on brands of water?
Thankful for any suggestions,
Donnette
Hello Donnette,
Wow, this is a puzzler. First, I’d definitely use bottled water for the time being. While it’s not necessarily perfect, bottled water tends to be consistent. I would use spring water, which can be hard, or drinking water, which is generally soft, but controlled for taste.
I’d give your local water department a call. Some municipalities soften their water or otherwise treat it. Yes, I agree the symptoms seem to match softened water. Another suggestion is to contact Bunn. They are extremely knowledgeable and have always been helpful when I’ve contacted them. But, first talk to your water folks. Let us know how it goes.
Warm regards,
Kevin
I’m having exactly the same problem. Just moved to a city known for its hard water aquifers. Without changing the coffee machine, filters, or coffee, it began overflowing the filter when I’d brew a 12-cup pot. The water drains from the basket at a snail’s pace, and there’s nothing mechanical stopping it. Adding a water softener changed nothing. A coarser grind seems to help. I’m planning to try bottled water to see if I can isolate the water as the problem. The next step will be to figure out what about the water is causing this.
Yes, David. Water is definitely an issue for many of us. Softened water is almost always worse. I live in a lovely community, but its water is unbearably hard. I long-ago changed to bottled water. I feel it’s the only way to achieve any kind of consistency. This is an area where I hope future progress is made, as many beautiful spots to live have the same issues.
Warmly,
Kevin
Part of my sales pitch selling water softners was to give the prospect two cups of coffee. One made with their hard water one made with soft from my little portable demo softner. They invariably preferred the soft water coffee. Coffee shops and restaurants typically use soft water for making coffee. I don’t know where your info comes from..
Hi Ed. Thank you for posting. If you’re saying you made coffee with salt-softened water in a standard half-gallon coffee maker I can only say I’ve had a different experience. The salt is present enough in the water to affect the pH and even affect the brewing process to its detriment. However, I’m ready to stand corrected by someone else’s demonstration. My information comes from both my own experience and that of my colleagues on the Specialty Coffee Association’s Technical Standards Committee. Again, I humbly offer to submit to a real-world test any time.
Warm regards,
Kevin
Personally, I think the comment about using water from a water softener in a drip coffee maker turn to “Goo” in the basket is a bunch of B. S.. We have been using a Bunn drip coffee maker for years WITH our water softener and have had zero problems. I do believe the single cup coffee makers do have a problem with soft water mainly because there are too many companies telling people to stay away from soft water in their single cup makers.
Hi Brad,
Maybe you’re right. After all, espresso makers often have salt-based softeners on them. Color me open-minded. Still, for larger batch makers in the commercial setting, I can’t believe it’s all mythology. It’s been so long since I’ve considered using salt-softened water that I don’t recall. I don’t currently have access to such water or I’d do a simple test.
Thanks for questioning authority.
Warmly,
Kevin
You mention salt based softeners, what about potassium based softeners?
Perhaps this would address the issue, as Potassium does not appear to have the same effect sodium does. Good idea.
Guy with a home water softener here. I just moved into this house and thought my grinder was measuring the coffee wrong. I kept ending up with a massive mess overflowing the coffee filter. Same grinder, same Bunn automatic drip coffee maker, different water and definitive results. The coffee tastes great though imo
Glad to hear it works for you. I’ve head so many reasons not to use a softener, I confess I’ve never tried.