Distilled water is water that has gone through a purification process that strips it of contaminants. For this reason, it’s quite popular and many people swear by it for health reasons.
However, distilled water is also stripped of magnesium and calcium, which are two minerals that are not only essential for health but also essential for flavoring things like, well, coffee.
Distilled water though does prevent mineral buildup in coffee machines (as well as irons and kettles), so people still use it. But can you use distilled water for coffee?
Yes, technically you could use distilled water for coffee, in that you will get coffee; however, it won’t be very good coffee and you’ve stripped the water of magnesium and calcium, making it less healthy than it could have been.
Why Water Matters
Coffee is over 98% water, so it makes sense that you want to consider the type of water you’re putting in your machine. Here are some things to consider:
- Water that is too heavy in minerals will be a bit bitter and can quickly damage your coffee maker
- Water that is lukewarm won’t extract flavor properly
- Water with too few minerals will over-extract your coffee and make it taste more bitter
- Soft water won’t change the flavor of your coffee and can be used to take out hard minerals
All of this means that you really don’t need any sort of fancy water to make good coffee – in many cases, cold tap water will do, assuming the tap water tastes good. Otherwise, using a water filter or a water softener will do the job.
So Why Not Use Distilled Water for Coffee?
When we think of coffee, we tend to think about the beans and the grind and overlook the water. But coffee is over 98% water and it’s the water that extracts the flavor!
So, it’s easily as important a consideration, if not more, as the bean – after all, it doesn’t matter how good the bean or the machine is; if the water is lousy, the coffee will be lousy.
In the case of distilled water, we have a fluid that has been purified. Now, that means it’s been stripped of contaminants, which is a good thing; but it has also been stripped of its minerals, which is a bad thing.
From a health perspective, it means we are losing out on calcium and magnesium. From a coffee perspective, we are missing out on a dimension of flavor that only tap water or bottled water can bring.
But distilled water has another problem when it comes to making coffee. Distilled water has a low ppm (parts per million) or TDS (total dissolvable solids) – about .5.
This low ppm contributes to the over-extraction of coffee, making it taste a lot more bitter. Normal water on the other hand has a ppm of 150, meaning that extraction is more balanced, and you get more flavor.
If you leave your coffee in the maker overnight, then the taste will get worse! The lack of minerals in distilled water also reacts with any metal in the water tank and that reaction leeches into your flavor.
Certainly, there will be people who don’t really notice a difference, but for those who have a bit more of a sensitive palate, coffee made with distilled water is going to taste more bitter.
Can You Use Distilled Water for Coffee from a Keurig?
No, using distilled water even in a Keurig (or any other coffee maker that uses pods) will still result in poor-tasting coffee. But in the case of a Keurig, it gets worse!
The sensors in a Keurig (particularly 2.0 and later), won’t pick up the presence of water, which confuses the machine. Older models will send up a warning message and newer ones can overflow.
Distill water also speeds up the corrosion of the heater elements, washers, boiler walls, and other parts of the machine, so you’re actually running it down faster than you would have if you were using tap water. So, you’ll end up with a mediocre, bitter cup of coffee, a confused machine, and a shorter life span for your Keurig. Not a good plan all around.
Can You Use Distilled Water for an Espresso Machine?
Ok, here’s where ‘distilled water, bad’ breaks down. For espresso machines, you actually can use distilled water, if you have a high-quality machine. The reason for this is because the extraction process itself differs in an espresso machine.
The puck of coffee grounds (as opposed to looser grounds in coffee machines) is harder for water to get through and the extraction has to be done fast.
This means that, unlike regular coffee where the extraction process takes a few minutes (and thus the minerals in the water can come into place), in an espresso machine, there’s no time for the minerals to get extracted, so no difference in flavor.
But this assumes that your espresso machine does not have an autofill boiler. Autofill boilers get confused by the lack of minerals and will assume there is no water and stop working properly.
What is the Best Water for Making Coffee?
The best water to make coffee with is reverse osmosis water, which is just filtered tap water. It keeps the minerals in the water and removes things like chlorine or heavy minerals that can damage your machine.
Otherwise, there’s nothing wrong with plain tap water, as long as you clean your machine regularly to prevent scaling. You can also use bottled filtered water or spring water, with some people swearing by spring water as the best water for coffee.
Now, you can use distilled water (we can’t stop you!) but keep in mind that it will change the flavor of your coffee and may contribute to the breakdown of Keurig machines.
If you have an expensive coffee maker, you may want to use distilled water to prolong its life, particularly if you don’t notice a change in flavor anyway (or you load yours up with flavorings, milk, and/or sugar and so wouldn’t notice any extra bitterness).
All in all, I would not recommend using distilled water for coffee. Even if you cannot taste the difference, you have removed essential minerals that contribute to your health and you may be causing different kinds of damage to your coffee machine (depending on what you’re using).
There’s no reason to go with expensive water systems for coffee – assuming your tap water tastes good, use it. And if not, a basic filter or water softener will do the job as well. Distilled water really only works with high-end espresso machines and even that may not do the job you want.
What kind of water do you use for your coffee?
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