WATER
The technicalities here are very high in number right from the PH value of the water, hardness or softness of water etc etc. These are parameters which are difficult to monitor and control hence we completely bypass them
(FYI the kind of technicalities specified – 6.5-7.5 PH water, 150 ppm dry residue, Bicarbonate levels of 50mg/l and much more.)
The thumb rule is water should not taste mineraly - these will scale the equipment you use and also lend a different taste which might make the coffee a bit more bitter. You can easily de-scale water by boiling it but that adds a completely different taste which is not that great either
Better use fresh tap water than any mineral water, unless you want to invest in a water purfier which does not add minerals
Other than the quality of the water the other major factor is the ratio in which the coffee is to be mixed with water. Here we take good help of the technical s. What they give us here is the amount of coffee to water that helps in extraction of the right amount of solubles in to the water and when will the coffee taste good
different researches give different ranges from 55-70 gm of coffee per a litre of water. 60 is the sweet spot. So 60 gms of coffee per a litre of water. That amounts to some where around a 100 ml of water per a table spoon of coffee grounds.
6 gms - 100 ml water
1 tea spoon = 5 gms (tea spoon is the smaller spoon)