Thick walled demitasses retain heat better - not!

[Abe Carmeli]

(split from another forum by moderator...)

I have to agree with Dan the thick walled demitasse cups are a favorite of mine and they are not readily available with the La Marzocco logo unfortunately. Many of you have probably heard this before but apparently aside from heat retention the extra thick walls help open the palate because you are forced to open your mouth even further than normal. Enhances the taste sensation apparently. I'd like to try em side by side sometime.

All true, except for the heat retention part. I hoped to dispel that myth on numerous posts I put on CG, but old legends never die. We did numerous tests on the thick walled demitasse versus thin walled like the Illy collection cups. There is no difference in heat retention between them. All the heat escapes from the top, not the walls.

[srobinson]

Abe, wow..talk about myth busting. Someone pointed me to some silicon espresso cups from MOMA last week that would be interesting to use your experiment on.

http://momastore.org/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=28272&langId=-1&parent_category_rn=10316&categoryId=10317&giftCat=null

They actually claim heat retention. I was in NYC last week, but they were sold out. Have you ever seen these?

[Abe Carmeli]

Steve,

I do not believe it would make any difference, since as I pointed out, the only way to retain heat is to put a lid on it. In our tests, only after 4 minutes you could see any difference between the cups. By that time, the espresso is indistinguishable from dishwasher water.

[shadowfax]

I want my demitasse with an insulated lid and a skinny coffee straw! yeah, that'd give me heat retention!

[HB]

Abe,

If you're referring to preheated cups in both cases, it doesn't surprise me that you wouldn't measure a difference in the liquid temperature over a minute or two. Besides, who lingers for several minutes over an espresso? But I suspect there's a perceived difference of thin-versus-thick due to the greater surface area the thicker cup presents to the drinker's lips.

(Re-reading the above paragraph, I'm wondering if I'm taking this espresso thing too seriously -- pondering the surface area of the lip of a cup, where does it end?!?)

[Abe Carmeli]

(Re-reading the above paragraph, I'm wondering if I'm taking this espresso thing too seriously -- pondering the surface area of the lip of a cup, where does it end?!?)

Dan,

This could have been a perfect opportunity to welcome you to the nuts jar. But I know that you had been there long before I pitched my tent.

[NewEnglandCliff]

OK, Abe, I'll set myself up.

Yes, heat rises. But doesn't a heavier cup act as a larger heat sink? And doesn't the heat from those cups rise into the espresso?

[NewEnglandCliff]

Could it be that while heat does tend to rise, that it will also be conducted into anything cooler regardless of the juxtaposition? In other words, since even a warmed cup will always be cooler than the espresso, the cup will actually draw heat from it (until there is an equilibrium).

If cold liquid were put into a warmed cup, the liquid would draw the heat and warm up. The more massive the cup, the warmer the liquid would get.

OK, so a thicker cup could draw more heat. But any cup will also radiate (ie. lose) that heat to the outside air. So wouldn't a thicker cup, being a larger heat sink, take longer to lose its heat than a thinner cup?

Does a thinner cup draw less from the espresso heat but radiate it more rapidly, while a thicker cup draws more heat while taking longer to deplete it? Is this a wash?

Still, as Dan says, that espresso will be in my belly before any real heat loss occurs. Interesting though.

[Abe Carmeli]

Cliff,

The physics behind it may be interesting. But the key to understanding why it does not work as we think it should, is the small amount of liquid in the cup and the short period of time in question. 1.5 -2oz of liquid exposed to such a large opening for 120 seconds. It is true that thick walls retain heat longer. And this is why after 3 minutes they are able to radiate heat back into the liquid, while the thin walls ran out of heat. But as we all know, espresso is not espresso after 3 minutes, and by that time it is so cold in both cups, that it makes no difference.

Once I started getting the test results I needed some higher authority to verify them. So we got a Physics professor from Australia into the thread. He ran the tests in his lab and came back with the same results.

Now, as to you talking to yourself on HB, I do it a lot. It usually involves me talking to my espresso machine, and in some extreme cases, to the coffee beans.

[NewEnglandCliff]

Abe,

Now, as to you talking to yourself on HB, I do it a lot. It usually involves me talking to my espresso machine, and in some extreme cases, to the coffee beans.

Well my girlfriend won't listen - she hates coffee. I'm often found wandering around the house muttering. At least here I have some understanding.

[luca]

Yeah, I think that you're on the money, Dan. Whenever I get people asking for "hot" coffees, my preference is to fill the mug, for it is always a mug, with water from the americano jet and let it sit until it's almost too hot to touch. Then I just make a normal large (ugh) latte/cap into it and the customer is invariably happy with it.

[espressobsessed]

Most espresso cups do come with a lid (aka: saucer).

If the customer is chatting and not ready to have his or her espresso, I put the saucer on top. It helps a little. If they don't get the espresso in 30 or so seconds, I'll bring it right to them, or else I'll have to redo.

And I don't like redoing a drink that is already perfect (ie: used a shot to calibrate the grinder and stabilize the group)