What is it about room-temperature coffee that makes it so unappealing? As your hot coffee cools down, it loses its freshness and oxidizes, which makes it taste more bitter, and the cup you pour your coffee into can have a drastic effect on its aroma, temperature retention, and your overall drinking experience.

You need to use a sturdy, thick-walled mug to keep your coffee hot, and a wider cup also increases your coffee's "headspace" and aroma. Mark Vecchiarelli of coffee accessory company KURVE explains that "Headspace, the volume between the liquid and the top of the glass, is a huge factor in creating room for the aroma to aerate."

A 2018 study by a group of coffee experts and amateurs found that coffee served in a "tulip mug" (with sloped sides) had a more intense aroma than the coffee in a "split cup" (a classic diner mug). However, coffee in the split cup was rated as sweeter and more acidic, and was preferred by coffee experts, but not the amateurs.