The Hario is a delicate and adaptable brewer for people who wish to master the pour. It's great for people who want to have full control over the brewing extraction process. The secret is a gradual, steady pour.
To get rid of the papery taste and preheat the cup or carafe you are brewing into, you can fold the filter into a cone and rinse it in the Hario dripper with water that has just come off the boil (approximately 205°F). Don't use the rinse water.
To make sure the coffee grounds are evenly distributed, add them to the filter and hit the container lightly. Put the brewer on top of a carafe or a cup, then put the whole thing on a digital scale and zero it out.
Prepare coffee that is as finely ground as kosher salt, using 21 grams. Put some coffee into the brewer.
Pour freshly boiled water (about 205° F) over the ground to saturate it. Don't oversaturate the ground; just soak it up. Wait 15 seconds, and then let it bloom. When coffee is freshly brewed, it releases gas (or blooms), and the coffee bed will rise and bubble slightly.
A gentle, even swirl of water added around every 10 to 15 seconds will provide a consistent extraction. Pour on the dark spots, but not on the light ones. Use a scale, and pour until you have 360 g.
You should have around 10 oz of brewed coffee at hitting 3:00. Take the coffee out of the brewer and pour it into a mug before you enjoy it.