Espresso drinking temperature

#1: Post by **rpavlis** » February 8th, 2013, 9:16 am

Much has been said and written about controlling brew temperature in espresso.

Another different problem is controlling the temperature of the espresso when it is the cup!

Cups are usually made of glass or porcelain. The specific heats of normal types of glass and porcelain are around 0.8 J/gram-deg. A typical cup weighs about 60 grams, so it has a heat capacity of about 50 J/deg.

Portafilters are usually made of brass--mine weighs 250. grams. Brass is a mixture of Cu and Zn, both have atomic weights between 60 and 65. Thus there are about 4 moles of metal in it, and all metals have molar heat capacities of about 3*R. (25 J/mole) Thus 4 moles of brass has heat capacity about 100 J/deg.

The heat capacity of water is 4.2 J/g-deg. Thus the heat capacity of a 30 g shot is about 125 J/deg.

The heat capacity of the portafilter and cup together is a bit GREATER than the shot! Using a cold portafilter and cold cup thus results in espresso that is lukewarm.

Many prefer to leave the filter basket in the portafilter all the time. It certainly helps keep espresso warm to weigh and tamp the filter basket while the portafilter remains on the machine and take it off just to insert the loaded and pressed filter basket. (It also avoids damaging counter top finish from porta filter spouts being pressed into them.) Leaving the portafilter on the machine while it is warming up helps a lot in my experience. Many like "bottomless" portafilters, this can help too, but greater heat loss probably occurs here from evaporation which almost certainly at least partly negates this advantage.

One can pre heat the cup by allowing water from the boiler to enter it prior to the pull. One can also put the cup in boiling water and dry it before the pull.

There are surfaces on many espresso machines where one can place cups to keep them warm too.

How do others deal with this?

#2: Post by **hamish5178** » February 8th, 2013, 9:44 am

Deal with what? Is there a problem?

#3: Post by **Mark08859** » February 8th, 2013, 11:12 am

Cup warmers tend to be a slow way of getting a cup heated; unless you leave your espresso machine on a long time before using it. Most folks will run some hot water from either the group or wand of the espresso machine. Some will use hot water from a faucet tap or even boil it. Whatever works for you, there is no one prescibed method.

AFAIK, most people (at least those that frequent boards such as this one) would drink their espresso within 10 seconds of brewing it. So temperature control in the cup shouldn't be a big issue.

#4: Post by **allon** » February 8th, 2013, 11:18 am

....and that's only because my head won't fit under the group....

More seriously, espresso flavors change as the shot cools. It's nice to taste those differences instead of searing your tongue and tasting nothing but pain.

#5: Post by **another_jim** » February 8th, 2013, 4:13 pm

In the past, and as a matter of espresso tradition, just as much effort goes into making sure the espresso is served hot as it is was put into making sure it brewed at the right temperature.

Cups are heavy ceramic and kept hot by the boiler
PFs are heavy brass and kept hot by the group. Back in lever days, when groups cooled off, they were flushed from the boiler
The shot is served at the counter, moments after it is pulled

This espresso tradition is in stark contrast with the equally time honored tradition of allowing fine cupped or brewed coffee to cool to luke warm before tasting it.

So is the espresso drinking tradition a survival from the days when espresso blends were made from low grade coffee? If the shot is made from blends using high end specialty coffees, should it be allowed to cool? Or is espresso its own genre, with different rules?

You heard it here first (or for the umpteenth time, depending on the reach of your coffee news network); but one of the major brewing arguments is whether espresso is just another way to make coffee or its own separate genre. Might make a good survey question.

#6: Post by **TomC** » February 8th, 2013, 11:25 pm

Mark08859 wrote:
AFAIK, most people (at least those that frequent boards such as this one) would drink their espresso within 10 seconds of brewing it. So temperature control in the cup shouldn't be a big issue.

I may be the odd man out then, because I almost always wait at least 10 seconds for it to cool a tad before I sip it.

February 9th, 2013, 1:25 am

I tend to like cooler brewed espresso (I find that my caravel and my TWIST, which brew rather cool, make the best shots) and tend to find a creamier mouthfeel at such temperatures. Ive measured this temperature in the boiler to be around 195-200 degrees. When I order at an espresso bar, I usually let the cup sit for a bit and enjoy the aromatics till it cools to the aforementioned temperatures.

#8: Post by **jonny** » February 9th, 2013, 2:43 am

TomC wrote:I may be the odd man out then, because I almost always wait at least 10 seconds for it to cool a tad before I sip it.

pacificmanitou wrote:I tend to like cooler brewed espresso (I find that my caravel and my TWIST, which brew rather cool, make the best shots) and tend to find a creamier mouthfeel at such temperatures. Ive measured this temperature in the boiler to be around 195-200 degrees. When I order at an espresso bar, I usually let the cup sit for a bit and enjoy the aromatics till it cools to the aforementioned temperatures.

At least there are three of us. Tasting a shot right away tastes sharp and one dimensional to me. Beyond a certain temperature, it is difficult to taste much of anything. This may be due purely to the tolerance to heat of my tongue. I may have a more sensitive tongue than some. After I pull my shot, I dump the portafilter, rinse it, wipe it, and rinse the group. After all of this, at a leisurely pace, 30-60 seconds has passed since the shot ended. Now I take a spoon and fold the crema a few times and proceed to sip it slowly over the course of a minute or two. Espresso has at least one similarity to brewed coffee; in a good espresso there is a spectrum of flavors which is a function of the temperature. I think one misses out if they drink too quickly. I've even heard barista competitors instruct judges to wait up to a minute and a half to taste the espresso.

#9: Post by **Peppersass** » February 9th, 2013, 2:45 am

I enjoy the flavors that emerge at the end of my espresso drink when I've consumed it slowly enough for the liquid to cool a bit. But while those flavors are interesting, they lack the aroma component that's present when I first start drinking from the cup. That's generally when I feel the espresso is at its best.

I've never measured the temperature of espresso in the cup, but I know it's considerably lower than coffee brewed in my vac pot. Heck, if I drink vac pot coffee immediately after it's brewed, I'll burn my tongue and lips. That never happens with espresso.

I think espresso is cooler because the stream cools slightly in the air as it falls from the portafilter to the cup, and the cup isn't covered or sealed up. I do stir the espresso a little before drinking, which may cool it off slightly, but I think it's already somewhat cooled before I do that.

Drinking really hot coffee is a losing proposition. In one of the vac-pot demonstration videos I watched a few years ago, the barista said, "We always let the coffee cool for 6 minutes after brewing. Otherwise, all you taste is 'hot', not coffee." I think that's very true of brewed coffee in general -- you have to let it cool down or you taste nothing but hot. I've never had that sensation drinking espresso.

#10: Post by **bostonbuzz** » February 9th, 2013, 8:59 am

I use a room temperature cup which is perfect because it cools the espresso right away and I don't have to stand around while it cools don in a hot cup. When I go to shops that have the same standard cups at 200 degrees on the top of their machine the espresso is always too hot for me.