How grinding can affect the taste of the coffee...
This is how it goes, everything and anything that goes into brewing coffee, would affect it. It can be something as small as cleaning the coffee maker to as major as temperature of the water.
Now, I did not say this, this is what I learn from a free coffee course, and one of the things which they bring out, is the grind of the coffee.
Anyone that brews coffee would have heard of the importance of coffee grinding. But, you probably understand it differently. For example, you would have heard about how important it is to get the fine coffee powder that can be used to brew espresso.
And I think this is where the misconception arises. Everyone start thinking that espresso fine coffee grind is the way to go, which in reality it is not so. What we want is to match the correct grind size to the right coffee maker.
However, we do need to have an even and consistent grind in order to achieve a good brew. And even and consistent grind are the 2 things to look for, and not a single type of coffee grind.
If you do not have the right grind to the right coffee maker, then it would result in either under extraction or over extraction. Which in both cases, give bad coffee...