You already know about grind. You already know about ratio. You probably already know about water temperature. But there is one variable that most home brewers underestimate, and it is quietly responsible for more mediocre cups than any of the others: the surface area of your grind.
Not grind size — grind distribution
Two brewers using "medium-fine" grind will not get the same result. The reason is not the size of the average particle. It is the distribution: how much of the grind is finer than the target, how much is coarser, and how much is exactly right.
A good burr grinder gives you a narrow distribution. A blade grinder — or a very old burr — gives you a wide one. Wide distributions mean some particles over-extract and taste bitter, while other particles under-extract and taste sour, and the cup ends up as an average of both. Which is to say, muddy.
Grind size sets the direction. Grind distribution sets the ceiling.
What to do about it
Three things, in order:
- Get a burr grinder. Any burr grinder is better than any blade grinder for the same money. The Baratza Encore or a Wilfa Uniform is a defensible entry point.
- Sift, if you must. A 200-micron sifter (Kruve or equivalent) will let you remove the finest fines. It is fiddly but it works.
- Adjust the recipe, not just the grinder. If your grinder is inconsistent, brew hotter or longer to compensate — but know you are working around a limit, not solving it.
The test
Brew the same coffee at the same ratio, on the same day, twice. If the two cups taste different — same water, same coffee, same brewer — your grinder is the variable. Fix that first, then worry about everything else.
Related: the full pour-over guide, which assumes you have already fixed your grinder.