Guides

What is the ultimate coffee cup or glass?

Coffee in a whiskey tumbler, enjoyed outside in the crisp Melbourne air.

I'll admit I'm jealous of the plethora of good looking, historical or just ergonomically brilliant glasses and tumblers available to wine and whiskey (and other drink) fans. But it confused me for a while. Take this tumbler. Coffee is amazing out of it, and not just because it's suddenly three dimensional and almost luminous with colour. I wondered - why is coffee more delicious out of certian receptacles? Why is glass and porcelain more effective for coffee or tea than ceramic and especially plastic, metal or paper? Apart from aesthetics, why are there so many different shapes of receptacle for wine (a far more developed culture)? What is the science to this?

There's as much art to science. But here's what I've found so far.

Whiskey tumbler

Glasses with wider mouths are better.

This is to allow your nose to absorb the aromas. A frequently cited opinion on coffee (particularly by non coffee lovers) is that the aroma is more delicious than the taste. You need to let the aroma in. A small cup is not conducive to this. In the case of espresso, a large receptacle might let the heat dissipate, so maybe it would work best to smell it before drinking it. But don't drink out of a cup with TOO wide an opening (like a bowl) as too much heat dissipation will occur.

Look for a smaller opening than the glass diameter.

This is important for aroma, which is an important part of the flavor experience. Aroma is positively correlated with the ratio of cup diameter to opening. However, it doesn't have an effect on flavor. In other words, you may be able to inhale the aromas more easily with an opening that is narrower than the body (perhaps due to a focusing effect), but this will not impact how you experience the liquid. 

Use a non-reactive, non-porous material. 

Preferred options include glass or porcelain. Metal is non-porous, and stainless steel is acceptable, but its high conductivity can cause a drink to lose its temperature very quickly (or warm up quickly, if it's a chilled drink). Paper is the worst option and so is plastic usually, though there are some exceptions. (This needs more detail, in an upcoming topic.) 

Aesthetics are important. 

It's pleasing to see the colour of the coffee. Pantone's color-of-the-year for 2015 is 'Marsala' which bears a striking resemblance to a lightly roasted pourover. Let that visual sink in! 

A round interior will allow swirling.

Square glasses may be attractive, but to allow aroma to escape the fluid, air needs to be introduced (as it does with wine). Naturally this will cool the coffee, but a good coffee should improve as it cools.