A master barista's guide to everything from caffe fredo to cold steeping and cold brewing—with an emphasis on proper technique and how to preserve true coffee flavor
With seemingly little thought, or plan, our beverage choices naturally evolve with the seasons. Full-bodied cabernets give way to light-hearted spritzers. Dark, malty ales yield to blonder lagers. For coffee, the iced kind takes a supporting role, if not a leading one.
Iced coffee is a global phenomenon with some good local color. In Greece, where per capita coffee consumption ranks among the world's highest, one-third of coffee is consumed as the iced coffee Greeks call frappe. Simple and refreshing: just combine ice, espresso, and simple syrup in a blender until it thickens like a smoothie, then pour over ice from your freezer. (Ice from a freezer tray is better to use than ice from a refrigerator's ice machine, which is usually less dense and therefore less effective at keeping frosty beverages cool.)
Why hot shots and not espresso cooled to room temperature? Because the nearly instantaneous cooling of the hot liquid preserves aromatic integrity—and aroma is the gateway to taste.
Moving along the Mediterranean, we land in Italy, where the trend now is cooling a single or double espresso in a cocktail shaker, with a lot of ice and maybe a little simple syrup (50 percent sugar, 50 percent water, boiled for five minutes and then cooled). Milk, Baileys, and coffee or vanilla liqueur are often added to create coffee cocktails. The Italians strain out the ice for a smooth coffee drink. This method yields far better results than the old-style caffe freddo, a cold coffee drink still served in many bars across Italy—a lot of espresso shots mixed with water and sugar, refrigerated for a couple of hours, then served straight in the glass.
Among the country's traditional cold coffee preparations are the Sicilian granita al caffe, espresso with sugar, quick-frozen until semi solid, and mixed several times during the freezing (for a recipe, see Corby's The Joy of Coffee); espressino, originally from Puglia, with one shot of espresso poured over three ice cubes in a glass; and Northern Italy's affogato ("drowned"), a shot of espresso poured over a scoop of vanilla ice cream. Simple and delicious. To the east, Germany's Eiskaffe is considered the inspiration for affogato: espresso with milk, over a scoop of vanilla ice cream, topped by whipped cream and shaved chocolate.
Whereby Israel's café kar gets down to basics—coffee, milk, and ice—South America's café helado is complex. Chile's version mixes no less than espresso, Chantilly cream, sugar, cinnamon, vanilla, chocolate ice cream, dulce de leche, and ground almonds.
Japan's aisu kohi is a mix of coffee, gum syrup, and milk, commonly found in cans. Ready-to-drink coffee and tea are Japanese staples, found in about every corner store and vending machine. Thailand's iced coffee contains cardamom, and in the Philippines, condensed milk lightens and sweetens things up.
Purist that I am, I stick with the hot stuff year round, for the aroma, the taste, the elixir-like qualities that only a freshly pulled espresso provides. And while iced may be the natural summertime call, hot beverages do a better job governing temperature perception under sultry conditions—in effect, producing a better cooling effect. The African Tuareg tribe, for one, travels camel-top across the Sahara sipping tea for mile upon sand-swept mile.
But the people have spoken. The time is right. Let's talk iced coffee technique.
Pour hot coffee over ice and you get diluted coffee. So logically, the idea is to melt as little ice as possible, making espresso ideal for iced coffee, owing to its relatively low volume and higher concentration. Rapid cooling is your goal, so pour just-pulled shots right over ice in a cocktail shaker (the glass and metal kind, not all metal), shake, and strain.
Why hot shots and not espresso cooled to room temperature? Because the nearly instantaneous cooling of the hot liquid preserves aromatic integrity—and aroma is the gateway to taste. Bottom line, you get the most "coffee-like" iced coffee experience with espresso. Sweeten and lighten to suit your taste. Use simple syrup or a liquid sugar substitute like blue agave instead of granulated sweeteners, which don't dissolve well in cold beverages.
Brewing coffee in high volume and then cooling in the fridge to satisfy a café's rush hour demands, or a week's worth of commuter travel mugs, is not the way to go. Refrigerating coffee promotes rapid and prolonged oxidation over time, doing irreparable harm to coffee's essential, aroma-harboring oils, accompanied by fast-escalating acidity. Two recipes for disaster.
The longer the cooling time, the greater the breakdown of harder-to-detect complex acids into simpler acids our taste buds perceive more readily. Darker roasts can help counter this breakdown to a degree. But the espresso-based rapid cooling method is the best way to maintain balance and fight sourness.
There is another way. Though not new, it's being newly rediscovered, and becoming something of a movement. Actually, make that two closely related ways: cold brewing and cold steeping. Each can produce stellar results.
Cold brewing and cold steeping rely on time rather then heat to transfer coffee's substances into water—a completely different kind of extraction from hot water. There are tradeoffs, because numerous substances in coffee can't be fully extracted without heat—most notably oils and certain aromas. But cold methods also giveth, by extracting fewer acids than heat-based infusions. The result is somewhat less aromatic but very clean—an almost sweet concentrate, neither acidic nor bitter. As with hot infusion, major variables impacting taste are the coffee's contact time with water, fineness of grind, and amount of ground coffee used.
As in hot coffee preparation, there are two "families" of cold extraction: infusion and percolation, which is also called transfusion. Cold steeping is extraction by infusion. Simply mix cold water and ground coffee, steep in the fridge for up to 12 hours, then strain and filter. It's quite similar to the traditional French press, and indeed a press pot serves cold infusion well. Remember to gently stir the coffee before placing in the fridge, and don't press down until the cooling is complete. Use a coarser grind—more readily trapped by the filter in a French press pot—and don't be stingy: you'll need about six times the usual one gram of coffee per one ounce water of recommended for hot French press preparation. Gear lovers can also find dedicated cold infusion devices, like the Toddy coffee maker, which has been around since the '60s.
Cold brewing is filter coffee's stone-cold brother, requiring special gear ranging in price from $45 into the hundreds of dollars. (Some adventurous types rig up their own cold brewers and spend nothing.) Picture a tall glass tower with multiple chambers and filters. Ice-cooled water drips from the upper part of the tower, where a special valve and a spiral-shaped pipe regulate the speed of the drops, ideally one per second. The drops run over ground coffee housed in a clear cylinder covered by thin tissue or a paper filter. Underneath, another filter prevents ground coffee from entering the next section of spiral pipe, from which finished, brewed coffee drips and collects in the tower's base. Cold brewing takes time—about 12 hours—so it's best done overnight. You might save a little time by using a coarser grind, and be willing to tolerate a less aromatic coffee.
With beautifully balanced, aromatic, chilled coffee as foundation, the power to create iced coffee perfectly suited to your tastes, and summertime whims, is all yours. Take inspiration from your favorite stop along the world tour we took earlier. Experiment with your shaker, with ice cream, liqueurs, sweeteners. Or, with nothing at all. Prepared correctly, starting with high quality, properly stored beans, your coffee will hold its own—even on the rocks.
Images (top to bottom): thebittenword.com/flickr, INeedCoffee / CoffeeHero