A Loud Steamer Wand Is A Huge Café Red Flag

Imagine walking into a café and hearing an ear-piercing, shrieking sound that seems a lot like nails being dragged down a chalkboard, sending a wave of goosebumps through your body. That's your red flag — a sign that you should turn around and walk back out of the doors because there is likely no good coffee to be found inside. The source of the screaming sound is the steam wand of an espresso machine that's being used to foam milk for thick cappuccinos and silky cortados topped with creative latte art, and not being used correctly by the sound of it.

The sound of a steam wand is one of the best ways to preempt the quality of java that you're going to get from a café because steaming milk is a work of art that's easier said than done. While the steam wand is used to heat milk, it's also what gives milk texture and creates microfoam, which is a type of dense foam that's responsible for giving milk its smooth, velvety texture. Ideally, the steam wand should sound like paper being gently torn for about eight seconds, after which all you should hear is a soft shushing. If what you hear is a shrill scream instead, it's a sign that your coffee is going to be flat, burned, and a far cry from the thick and creamy that well-steamed and aerated milk should give it.

Why does a steam wand scream?

There are several reasons why the gentle paper-tearing sound of a steam wand can turn into the scream of a banshee. A steam wand essentially does two things: It heats the milk in the pitcher and uses air to create tiny bubbles inside the milk, which is what makes the liquid thick, frothy, and flavorful. While the heating part is relatively straightforward, it's the aeration bit that requires more skill because even something as simple as not putting the steam wand at the right angle inside the pitcher of milk can cause loud screaming.

Ideally, dairy milk should be steamed gradually and aerated using a rolling current that slowly mixes the milk with air. If the steam wand is placed too deep inside the milk (where it can't be aerated), the steam will get trapped beneath the surface. Eventually, the pressure of the heat will explode and leave a screeching sound in its wake. Another culprit could be the reusing and reheating of milk, which can both cause the piercing sound, as can the quantity of milk. A pitcher should typically be filled at least one-third of the way with milk for the steam wand to have enough liquid to work with — any less and you may very well hear the loud scream from the steam wand before you even enter the establishment. This can lead to burned milk, which won't taste nice in your stepped-up coffee order.

Other café red flags to watch out for

While a loud steam wand is a telltale sign that you're about to be served a mediocre cup of coffee, it's not the only café red flag to be on the lookout for. There's a lot that you can tell about a café by simply looking behind the counter: Is milk being left on the counter instead of being put back in the cold temperatures of the refrigerator? Are the steam wands yellow with the crusty residue of hot milk? Is the condiment bar splattered and trashed? Are the pitchers not being cleaned each time they are used to steam milk? If so, it's best to lower your expectations for the coffee you're about to get inside.

You can also weed out an excellent café from a subpar one by seeing whether they grind their own beans. Coffee tastes best when the beans are ground fresh, so the presence of a grinder can be an excellent way to gauge how much the café cares about coffee. If you'd really like to get into the details of things, you should also observe the hopper on top of the coffee grinder that holds the coffee beans. If you see oily residue on it, the hopper likely hasn't been cleaned in ages — which makes the café's cleaning standards questionable. And if the establishment doesn't care much for cleanliness, who's to say that they care much about the coffee that you're about to be drinking?