Q: A few weeks ago you were talking with a guest about how to recognize high-quality espresso. I worked for many years as a barista (an Italian term for the person who makes espresso in a coffee bar) and it made me very critical of the milk used in coffee drinks. The quality of the milk used and the way it's handled makes a big difference. My advice when buying at a coffee bar or cart is to stop, look, and listen. Milk is a perishable substance that we tend to take for granted. It should be kept refrigerated and look for a clean pitcher. If you see caked milk residue along the top edge of the pitcher you should suspect that it may not be handled properly.

Lynne: Should they discard any unused milk from the pitcher and start fresh for each coffee drink ordered?

Q: In an ideal situation, yes. I was trained rigorously to rinse the pitcher with cold water between orders and wash the pitchers thoroughly each hour. Those are the details that get overlooked when it's busy or high standards aren't employed in an establishment.

Lynne: You said stop, look, and listen. We've stopped and looked. What about listening?

Q: If you go into a coffee bar and hear them steaming the milk it means they're not handling it in a gentle enough fashion and the steam wand is just on the surface of the milk, not submerged in it. When milk is being properly steamed you don't hear it much - maybe just a small gurgling sound, not a loud whoosh.

Lynne: Thank you - this stuff is really high art. Will any of us watch someone make an espresso coffee drink in the same way again?