We are all guilty of measuring coffee with the trusted teaspoon, let's face the fact, it's a lot more convenient & if i'm really really lazy, i'll just leave my teaspoon in the container (after all, i'm using it on a daily basis)!
I'm guilty of this as well, until i was introduced THE SCALE, being a little skeptical, when i picked it up from a coffee appreciation seminar, i decided to give it a shot. I invested in a small kitchen scale (make sure it's able to provide measurements in very small quantities, i.e 1g).
I'm amazed at how this 1 simple change in my daily coffee brewing routine has made a whole lot of difference.
Weight matters - weigh it!
No two beans in a bag are similar, scoop a handful out of a bag and look at them. They're not at all uniformed. Besides that they are all round instead of flat, it's impossible to expect them to lay perfectly evenly or compacted in a coffee scoop, teaspoon, tablespoon & it's likes. This measurements are vague as they way i scoop a tablespoon will be a little different from yours.
For a standard espresso shot, it's about 10 grams of coffee, so a difference of 2 grams will throw your whole recipe out of whack or at the very least give you an inconsistent flavour.
Still not convinced below is an example. I needed about 50 grams of coffee for a brew and conventional wisdom would say that's 7 tablespoons. Look what 7 tablespoons got me!
If you are thinking ground coffee will do the trick, don't bother. Just so you are convinced, i've measured 4 tablespoons each of ground coffee and whole beans. The difference is nearly 5 grams, and what's interesting neither gave me the 30 grams that I was aiming for.
Keep in mind that all ground coffee is not equal, a coarser grind will yield more volumetrically than a fine grind, but the latter will be typically denser, so you'll wind up with more coffee.
Consistency is Key, this can be achieved with an inexpensive kitchen scale. With a scale you will use the right amount of coffee beans/powder every time you make yourself of cuppa, this also lets you to adjust the strongness accordingly. If you've got yourself slightly mild beans, go ahead, add a little, just be sure of the measurement so you can get the exact same cuppa again & again!.