# Crafting the perfect cappuccino is all about math Add to ...

If you wander into a Roman café after noon, don’t dare ask for a cappuccino. You’ll get laughed at, or at the very least, get some cut-eye. In Italy, the cappuccino is for morning consumption only and is a carefully crafted beverage of strict proportions, no more than six ounces.

“The reason it’s such a small drink is because it’s a drink of thirds,” says Sam James of the Sam James Coffee Bars in Toronto. “If the espresso is two ounces, then it’s two ounces of milk and two ounces of foam.”

The density of the foam is crucial to the makeup of the drink, which is why a cappuccino won’t be nearly as good if it is doubled – not to mention quadrupled in a paper cup such as Starbucks’ “venti,” which is a whopping 24 ounces. At that size, it is no longer a balanced drink, likely with a disproportionate amount of espresso and overaerated foam. There will be more and bigger bubbles, resulting in a chalky mouth feel, James says.

“So much about the cappuccino is about fine touch and finesse,” James says, noting that this particular combination of espresso and milk is the hardest to master. “It’s more than just making a good espresso. It’s timing, steaming milk at the right temperature and putting it all together in a timely fashion.”

Pull a shot of espresso too early and it oxidizes quickly, losing aromatics. Leave steamed milk out too long and it might separate, losing its desired homogeneous creaminess. Foam is finicky and if prepared poorly, it can be disjointed and lumpy.

The proportion of thirds, prepared by a practised barista and served in a proper tulip cup, provides a perfect cappuccino. It is a drink with a fragrant espresso, silky steamed milk and dense foam for a combined plush, slightly sweet experience.

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