French press coffee is dense and heavy, yet it has its own sort of elegance. As with any method, the devil is in the details: To achieve a full expression of the coffee, decant it immediately after brewing so it doesn’t become bitter or chalky. Then, sink into this rich and heady cup. It only takes four minutes to brew.
• Bring enough water to fill the French press to a boil. For a 17-oz press, you'll need about 350 grams (12 ounces).
• While the water is heating, grind your coffee. French press coffee calls for a coarse, even grind. We recommend starting with a 1:12 coffee-to-water ratio. If you're using 350 grams of water, you’ll want 30 grams of coffee.
• To start, gently pour twice the amount of water than you have coffee onto your grounds. For example, if you have 30 grams of coffee, you’ll want to start with 60 grams of water.
• Give the grounds a gentle stir with a bamboo paddle or chopstick. Allow the coffee to bloom for 30 seconds.
• Pour the remaining water and place the lid gently on top of the grounds. Don’t plunge just yet. Let the coffee steep for four minutes. Four. Don’t guess.
• Gently remove your French press from the scale and place it on your counter. Press the filter down. If it’s hard to press, that means your grind is too fine; if the plunger “thunks” immediately down to the floor, it means your grind is too coarse. The sweet spot, pressure-wise, is 15–20 pounds. Not sure what this feels like? Try it out on your bathroom scale.
When you’ve finished pressing, serve the coffee immediately. Don’t let it sit, as this will cause it to continue brewing and over-extract.
Source: Blue Bottle Coffee