For better coffee, there are a few things you want to avoid
Using a French press is one of the easiest, most satisfying ways to make coffee. All you need to do is add grounds and water, wait, and then press down that plunger. Hey, presto: coffee! But sometimes you get a cup that is, let's say, grainer than usual, or doesn't taste quite right. Never fear. You're probably making one of these pretty common but easily rectifiable and avoidable French press mistakes.
You're Grinding Your Coffee Beans Too Finely
The filter on a French press is designed to catch the coffee grounds and prevent them from seeping into your cup, but the filter isn't as fine as it would be for other methods. For an optimal cup of French press coffee, you want to make sure that your grounds are coarse, roughly the size of sea salt or kosher salt. That will ensure that the coffee brews properly, and prevent you from getting those unpleasant floating grinds on your cup of coffee.
Your Water Temperature Is Too Hot
Turns out that bringing a water to a boil isn't quite what you want for a French press. In fact, the optimal temperature for a French press to brew coffee is 202 degrees Fahrenheit, ten degrees below boiling. If you have a fancy tea kettle, you can just set it to brew at that temperature—but even if you don't just wait 30 seconds to a minute after your water boils so it's hot but won't scald the grounds.
Your Coffee to Water Ratio Is Off
Let's be real, not everyone has the time or patience to weigh out their coffee and water in the morning. But if you figure out about how much you should use, it can go a long way to make a better cup in the morning. The ratio that Blue Bottle Coffee recommends is one part coffee to 12 parts water, though you might prefer a cup that's weaker or stronger. So work out how many cups your French press should make and work from there to figure out the optimal amount of coffee and water to put in.
You're Brewing the Coffee for Too Long
If you just leave the French Press on the counter to brew for a long time, you're likely to end up with a bitter cup of coffee. You want the grounds to mingle with the hot water for four minutes. No more, no less.
You Leave the Coffee In the Press After Plunging
You should pour all the coffee out after you're done plunging that sucker. Otherwise, it'll continue to brew and take on a bitter, unpleasant flavor. Even if you're not drinking it all right away, transferring it to a different carafe will make a big difference if you're hoping to savor more than one cup of coffee.
See? It's not so hard. Before you know it you'll be making French Press coffee like a pro.