Hello everyone!

I have recently been experimenting with different waters for coffee, only to discover what everyone already knew: yes, water has a big impact on your coffee! I tried Third Wave Water which is delicious but does not really offer a lot of flexibility to try new things. There are some excellent posts online on the influence of water, like this one from Coffee ad Astra:

https://coffeeadastra.com/2018/12/16/wa ... xtraction/

Basically, there are two important things: the general hardness (which is Calcium and Magnesium) and the alkalinity (which is Bicarbonates). In the above article, there are plenty of different recipes for water which are recommended (actually, there is a whole zone of recipes to explore...).
I was interested in trying some of those recipes without having to buy minerals, make concentrates and mix it all, so I chose what I thought was the easiest way: mixing different bottled waters. To this aim, I wrote an algorithm which can tell me that if I am aiming at a water recipe with 87 of general hardness and 40 of alkalinity, I will need to mix 3 of the given waters respecting certain proportions (for example 80% of one water, 12% of another and 8% of a third one). It was working quite well (at least with the waters I have available) and I thought that such a tool might also be useful for other people. Therefore, long story short, I made it as an android app to give recipes for mixing different waters.
The app is called CoWaMix (for Coffee Water Mix), and it is available right now on Google Play Store:

https://play.google.com/store/apps/deta ... et.cowamix

It is available for free and there is no registration needed. To use it, you first add the waters you have available in a list with the necessary information (magnesium, calcium, bicarbonates...this can be found on the label of the bottle or online). Afterwards, you set the objective values for the general hardness and the alkalinity, and the app will try to mix the given waters so that the objectives are reached. Once you have a mix, you can save it to your recipes. For each saved recipe, you have the option to choose a quantity of water you would want to mix, and the app will tell you how many grams of each water in the recipe is needed to get the desired quantity.

Feel free to download the app, ask questions, give feedback, share it, etc. It was written as an amateur app on my spare time (I am by no means an app developer or a coffee professional), so if you spot any issues, please let me know and I will do my best to fix it.

I hope such a tool can be useful to this community!

I often mix water for making coffee, it dramatically changes the taste of coffee, but only true coffee connoisseurs know about it.

It does change the taste a lot... do you have a favorite mix?

This seems a great idea and I do it with my well water but a note in case the thread turns into people sharing water mixing recipes. The smaller water companies probably are only local, so not many will have access and the more widespread water companies usually offer different sourced water in different geographical markets. For example Crystal Geyser has a half a dozen or more water sources and each have different profiles - some fairly hard and some fairly soft. So if recipes are shared, look on bottles for source of water.