Boiling Point

October 27, 2011 7:11 PM

What is the minimum water temperature that will give me enough caffeine / taste from french-pressed coffee grounds?

I've been staying in Zuccotti Park for about three weeks and basically my only daily expense has been the ~$6 I spend on coffee (Kitchen Work Group buys their coffee from vendors on the periphery of the park at $25/vat, which goes really quickly in the morning). I have a french press back in Brooklyn that I'd like to bring over so I, and the people in my sleeping area, can just brew our own coffee throughout the day.

The only problem is that there isn't really any boiling-water access nearby, save the coffee carts. There are, however, plenty of hot-water-for-tea spouts on-site and in surrounding area. Will that water be hot enough to brew french-pressed coffee? Any big negative effects to taste/caffeine?

Or would an alternative idea, like working out a deal with the coffee carts for ~$1/pot of boiled water be an easier solution?

posted by NolanRyanHatesMatches to food & drink (14 answers total)

I don't really understand what a hot water spout for tea is if it isn't boiling or very recently boiled water. But if it's hot enough to get a good brew from teabags, it should work for coffee. I'd try it and see. I use our zip in the office for french press coffee without trouble, and it often isn't quite boiling, I think.
posted by lollusc at 7:23 PM on October 27, 2011

The coffee shop I used to work at used water at 185-190 degrees Fahrenheit. I recall being warned against using water warmer than that, though not the reason.

So I'd think if it's hot enough for tea, it's hot enough for coffee.
posted by AV at 7:24 PM on October 27, 2011

It should be fine if it's hot enough to brew tea. Coffee brews best around 185-200F, a bit below boiling, if you want some specifics. And caffeine is fairly soluble at even lower temperatures, IIRC.
posted by mccarty.tim at 7:25 PM on October 27, 2011

you could use your french press to make cold brew coffee.
posted by phil at 7:25 PM on October 27, 2011 [3 favorites]

Hot water for tea will be hot enough to brew coffee, as long as you can keep the press warm through the steeping process. Coffee brews best at 195-205 degrees F, but cooler water will work with a (possibly much) longer steeping time. The water coming out of those spouts is likely at least 180 F.
posted by WasabiFlux at 7:26 PM on October 27, 2011

AV: The reason they don't want it hotter is so that you only extract the flavors you want from the coffee. IIRC, coffee that is brewed too hot tends to taste overly bitter. This is why people buy more expensive drip makers, as they pour the water on below boiling, unlike the cheap ones that just pour on boiling water.
posted by mccarty.tim at 7:26 PM on October 27, 2011

I find the magic temp for optimum flavor is around 175/180 for my Aeropress
posted by any major dude at 7:29 PM on October 27, 2011

Cold-brewing coffee works perfectly well and tastes different but not worse than "normal" french press coffee. It does take all night (at least).

I didn't look it up in a citation-worthy way, but the internet suggests that while the solubility of caffeine in cold water is much lower than in hot (2.2 mg/mL at 25 °C vs 180 mg/mL at 80 °C), that's still plenty: half a liter of coffee/water could dissolve a little more than a gram of caffeine, which is way more than you would want (and still way more than you're getting out of your grounds even using boiling water extraction).
posted by pullayup at 7:38 PM on October 27, 2011 [1 favorite]

Ah, thanks everyone! When I brew at home, I usually boil -> wait 30 seconds -> pour into French press -> filter after four minutes.

However, I wasn't really sure if the hot water from the "hot water" nozzle usually used for tea would be hot enough coax out the necessary caffeine from the coffee. From these answers, it sounds like temperature really doesn't make too much difference w/r/t caffeine content and might have more to do w/ extracting the right flavor, given that I let the coffee sit a little longer. I'll give 10/15 minutes a go tomorrow and see how that works. Thanks!
posted by NolanRyanHatesMatches at 7:41 PM on October 27, 2011

This cold brew method uses a french press with a good explanation of the process on the other hand you can have cold brewed coffee delivered by bike from Brooklyn.
posted by hortense at 7:50 PM on October 27, 2011 [1 favorite]

It may be more of heat speeds up the process of extraction, so it can matter irt caffeine content depending on how long you are willing to wait. Cold brewed coffee does have some advantages, primary of which, it tends to be less acidic than regularly brewed coffee.
posted by edgeways at 8:06 PM on October 27, 2011

Heat does speed up extraction. The hot water for tea will work great. I had a french press in college, and hot water out of the tap worked just fine.

BTW, thank you for taking part in the demonstrations.
posted by glaucon at 8:18 PM on October 27, 2011

My Aeropress actually recommends 175 degree water.
posted by leahwrenn at 5:14 AM on October 28, 2011

In theory the water temperature for the hot water faucet on a coffee maker should be the same temperature as the water that makes the coffee, which should be around 180 degrees, so it should work ok. For brewing info this site has good info as well as here.
posted by atlexpress at 9:59 AM on October 28, 2011