[kaolinite]

Do you mean the amount of water you use? It's important to measure both the amount of water and the amount of coffee so it's consistent. I personally use 22 grams of coffee per 300ml. It's a personal choice though and it depends on the coffee and method of brewing too: for you that might be too bitter, too strong, too weak, etc.

Here's what I do with a Chemex. I put the Chemex on the scales, add the filter and hit tare (so it's now weighing 0g). I add the 22g coffee and hit tare. Then I add 300g of hot water (same as 300ml). It produces the same cup of coffee every time - exactly how I like it. Obviously, if I ever change the coffee I get (or the coffee I get now - currently an espresso blend which is blended for consistency - changes significantly), then I might need to experiment a bit and see whether 24 grams of coffee is now my preference, for example.

[xsace]

Oh I was speaking about the water itself. Do you filter or use bottle one?

[josteink]

Tap works for me and I'm picky, but I recognize that not everyone in the world lives somewhere where the tap-water is usually better than the bottled water bought in stores.

[amelius]

Mineral content in tap-water can vary, even between places where tap-water is very well potable. Minerals can affect taste, according to [1] (I didn't check myself).

[1] http://blogs.discovermagazine.com/d-brief/2014/06/06/the-sec...

[kaolinite]

Oh right, I've not actually tried altering the water - I really should give it a go sometime. I just use tap water - the water in my area is ok. That's another one of those things that may make a bit of a difference, but nowhere near the difference that getting good coffee and measuring properly will make. Of course, if you're already doing both of those then there's no reason to give it a go. Thanks for the idea.

[jimbobimbo]

I buy bottled. The taste is better and consistent. If you go this route, make sure to try different brands (they use different water sources, so the taste will vary).

[pconner]

You should use filtered (but not distilled) water to make coffee. This slows down scale buildup in the machine.