Ideal coffee grind for a French Press?

Question

I recently picked up this Bodum "French Press" style coffee maker and so far, I'm really enjoying it for its simplicity. But I'm curious how I should be grinding my coffee.

When I bought it, I grabbed a bag of pre-ground coffee at the grocery store and this worked well. But recently, I bought a can of beans and put it thru the coffee grinder at the store and I may have chose too coarse a grind as I seem to be getting very weak cups of coffee now.

The manual said pick a "coarse" grind, so it turned the dial all the way to the left labeled "coarse". I'm thinking it should have been somewhere in the middle, like "Percolate".

Any advice on the optimal grind?

EDIT: Also, What ratio of Tbsp to oz of water? (or grams to ml, if you prefer metric.)

Answer

You do want a coarse grind for french press coffee. The key is letting the coffee steep for long enough to make a strong brew. I have good results with a 5 minute steep time. Be sure to use a timer, and compare different times to find the optimal brew. As a general rule, if you are at altitude, then you need to add time because boiling water is cooler. (Note that I am at 5000ft, so 5 minutes may be too long for you.)

Below is a picture of the coffee chunks in a coarse grind on top of a US 10 cent coin (17.9 mm in diameter).

EDIT: The reason to use a coarse grind for a french press is that finer grinds will get stuck in the filter and/or push their way through. This has three potential problems: 1) it will be harder to press down the filter, possibly leading to spillage or breakage; 2) your coffee will have grinds in it; 3) the coffee may become bitter, as the finer grinds that passed through the filter remain in contact with the coffee for too long.

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