When I first bought a French press, the instructions said to pour hot but not boiling water over the coffee. They were emphatic about what the temperature should not be, but vague about what it should be. (Boiling water extracts oils that you’d rather leave in the grounds; water a little cooler brings out just the oils you want.)
I asked someone online—sorry, I don’t remember who—and he said that after your water boils, set the kettle off the burner and check your mail. When you come back, the water should be at the right temperature. That turned out to be good advice.
I don’t know whether he meant postal mail or email, but it doesn’t make much difference. Unless you get caught in replying to email and come back to room-temperature water.
Now if you really wanted to geek out on this, you could use Newton’s law of cooling along with the surface area, thickness, and material composition of your kettle to compute the time to let your water cool to 200 °F (93 °C). You could assume a kettle is a half sphere …
Related post: A childhood question about heat
Actually, the temperature is only a side-effect here. There is no, one, perfect cup of coffee. Rather, the technique ensures that your java is right for you, right now.
The really important part is checking your mail. Perhaps you received no mail at all. This leaves you intellectually unstimulated and in need of a coffee brewed hot and quickly. Or maybe you received one, interesting message. 200° and a longer brew is the right solution here. If you received a mountain of junk mail, then the cooler water caused by the amount of time required to sort through all of it followed by a quick steeping since you have nothing left to read will result in just the right coffee for your current state of mind.
It actually doesn’t matter if you check e-mail or snail mail; this technique works well with both of them.
:)
Or if you want to be a real geek, buy an Arduino, hack it up and build your own specialized thermometer:
http://lemire.me/blog/archives/2010/12/24/make-your-own-programmable-digital-thermometer-in-an-hour/
;-)
I use an AeroPress, essentially a manual vacuum press that forces the water through the grounds and through a paper filter. It uses a finer grind than a drip process and much finer than a French press.
Experience has provided the time to microwave a measured volume of tap water in a Pyrex measuring cup just to the point of boiling. In the time it takes to transfer the measuring cup to the counter where I press the coffee, it has cooled to around 95°. I pour in a small amount of water to wet the grounds and stir it, pour in more water to fill the press (at which time the water is probably 90° or cooler), stir, wait a few moments, and press it.
Perfect coffee every time. But now I can’t stomach regular drip coffee.
If you decide you don’t want to drink up a full French Press at one sitting, try an Aeropress. They’re pretty awesome.
Also, if you use one of those self-shutting off electric kettles, the water ends up just about perfect 30 sec or so after it shuts itself off.
Or just use a Thermapen ;)
I just pour the boiling water into a pyrex measuring cup, up to the 2/3 or 3/4 cup level. The act of pouring into a room-temperature container brings the water down to about 200F — I’ve checked. Plus it’s easy to measure the right amount of water at the same time.
The electric kettle that came with my rental flat has options to heat up to 85°C, 95°C or boiling (and lights up different colours as it does so). When I moved in I thought it was ridiculous…but I’ve come to really like it.
http://www.morphyrichards.co.uk/products/kettles/jug-kettles/43870-Intelliboil-Jug-Kettle.html
I have another tip on using these things. Don’t try to climb into bed whilst naked and carrying one of these things on a tray.
Of course, you would have to be a dumbass to do that, but I have it on good authority that such dumbasses do exist.
Oh, and if you are going to try the climb into bed stunt, John’s tip on letting the water cool a bit first will also help ;)
You forgot that water boils at different temperatures, depending on altitude. I live one mile high and water here boils at 94.4 C, or almost already your recommended 93 C.
mbaz: Good point. I’ve lived most of my life at sea level and forget about the difference that altitude makes.
I’m a bit late to this post, but I’ve had success by just covering the coffee grounds with cold water and swirling the coffee pot to mix, then pouring in the boiling water as soon as it’s done.