I have reasonable tap water at home, but filtered water does taste better here. I posted a blog entry comparing the water available to me here…
Today I wanted to compare the waters in coffee. Obviously just because they taste differently and rank one way as water does not mean that they would rank the same way in coffee. I would love to test it in espresso, but I cannot think of a good way to do that with only one espresso machine. Espresso changes quickly over time and a shot does not even taste like itself if you drink it several minutes later, so changing out the water in the machine would be virtually impossible in the time it takes to have the shots taste similar. Two identical machines would fix that problem. Hmmm. (okay that dream lasted about 10 seconds and then I remembered my wife would kick me out if I tried to pull that stunt).
Instead I decided to try the experiment with pour over coffee. I took the winner and the big loser in my water contest and put them head to head. The winner was the filtered water that was never in my boiler. The loser was the unfiltered tap water. I figured if they tasted the same there would be no point in trying the waters that fell in between.
I used Deep Cello Bossa for the coffee since it is good and I have it in hand. I made the cups with my Timolino (clever like) drippers since I have two of them. In both cases I boiled the water and let it cool to the same temp (185). Some day I would love to test two waters at the same temp, but one of which boiled first and the other of which did not. Some say these two would taste the same and others say they would not.
Now for the results. They taste similar, but different. The filtered water is a cleaner cup and the tap water is muddier and there is a slight, but very slight off taste that carries through. The off taste is much more subtle in the coffee. Interestingly as they have cooled the difference has increased with the off taste getting worse.
The unfiltered water makes for a more powerful and potent cup, perhaps because our water is soft and the coffee needs some hardness to find something to cling to (thus the advice never to use distilled water).
Will I use filtered water in the future? Yes I think I will. It is enough better to be worth it, but not by much. It would probably be far more dramatic if our water was worse or harder – we have fairly soft water so there is not that much for the filter to take out in the first place.
Alas this means I better try the filtered water against the boiler water since I now know there is a difference in coffee produced with different waters in my house and so it is not unreasonable to think the filtered boiler water may taste different from the filtered non boiler water..