The Best Ways to Make Iced Coffee, Tested
Contrary to the popular idiom, there's actually only one way to skin a cat: very awkwardly. But when it comes to making iced coffee, there are plenty of different methods. Some people cold brew overnight, others try Japanese flash-brewing, and then there's the literal-minded folks who just throw caution/taste buds to the wind and dump a bunch of ice in their mug. But which method makes the best cup?
Since even the laziest of these methods has pros and cons, we enlisted coffee extraordinaire Lorenzo Perkins (owner of Fleet Coffee in Austin, TX, and member of the Barista Guild Executive Council) to do a side-by-side test to find out how the brewing technique affects the coffee, which has now transcended the "summer drink" category to become a year-round fix.
To make sure we hit both the light and dark sides of the coffee spectrum, we used two types of beans: Counter Culture's Big Trouble, a darker Guatemalan/Honduran blend described as “caramel, nutty, and round,” and Madcap's Summer Solstice, which combines two lighter Ethiopians resulting in a cup that's “fruity, creamy, tea-like, and refreshing.”
Our brew methods were as follows: cold brew (aka “toddy”), hot bloom cold brew, flash brew (aka Japanese), refrigerating hot coffee, and just putting ice in hot coffee.
For all of our hot brewing, we used a Chemex, which we choose because it's a simple pour-over method known for creating a well-balanced cup (and both Lorenzo and I are too snobby to own a drip machine). For our cold-brewed coffees, we batched them as concentrates, but tasted them at both full and diluted strength in order to get the best impression of the flavors (sleep schedules be damned!). Here's what we discovered.
Refrigerated hot coffee
Method: 45g coffee, 750mL water, left in a Chemex in the refrigerator
Dark roast: Smells like old tires. Super bitter, way flat -- the only thing that you can taste is darkness.
Light roast: The fruit flavors are completely washed out by a strange vinegar taste. Heavy notes of cardboard and tonic water. Aftertaste lingers on your jaw uncomfortably, like a goatee.
Overall: Both coffees had a strange, cloudy texture that Lorenzo offered to come up with some pseudo-science explanation for, but after racking his brain he concluded that it was just plain weird. The color, mouthfeel, and flavor were awful, and the only reason he said he would drink this is if he was on four hours of sleep and had to wake up to do manual labor.
Hot coffee poured over ice
Method: 45g coffee, 750mL water, brewed in a Chemex, then poured over ice
Dark roast: The old tire smell present in the refrigerated version made it into the taste. This was the only coffee that Lorenzo spit out.
Light roast: Tastes like weak tea. There's some coffee bitterness, but the astringency makes it undrinkable.
Overall: This method prevailed over its refrigerated cousin because it tasted more like actual coffee, albeit a weak, flat, and lazy version.
Hot-bloom cold brew
Method: 45g coffee, 400mL water. Boiling water was poured over the grounds in a Chemex, then the grounds and water were left to steep overnight.
Dark roast: Smells nicer than normal cold brew, and is very nutty. The milk-chocolate flavors come out, and it's not nearly as bitter as the hot-brewed methods. There's still a dry finish, but it makes for an interesting, full-bodied cup.
Light roast: Smells fantastic. The plum and apricot flavors aren't kidding around -- it's like actually biting into a piece of fruit. And even though it's highly concentrated, there's still great sweetness.
Overall: Initially, the hot-bloomed Madcap was the most exciting coffee on the table. Lorenzo, as well as our hosts at Figure 8 Coffee Purveyors, expressed serious interest in chugging the whole jar. But as it cooled, the fruit flavors began to sour and it became too intense. This is the coffee equivalent of a sour beer: it's a wild ride, but would overwhelm many people's palates.
Traditional cold brew
Method: 45g coffee, 400mL water, left to steep overnight
Dark roast: More bitter, darker chocolate flavors than the hot-bloom method. Low acidity, medium bitterness, a little tobacco finish.
Light roast: If the hot bloom is tea with a fresh squeeze of peach, this is a tea that's been mellowing out for a while. It's a bit staler and mustier, higher in acidity, and with some nutty nougat on the tail end.
Overall: This is the most drinkable of the bunch. It goes down easy, isn't as in your face, and the Counter Culture would be especially killer with cream and sugar.
Flash brewed (Japanese)
Method: 45g coffee, 500mL water. Chemex filled with 250g of ice, coffee brewed directly onto the ice (instructions right here!).
Dark roast: Everything's mellowed out. The roast characteristics don't dominate anymore, and the aromas are subtler, but the acidity has increased, making this taste more like actual coffee (in a good way).
Light roast: The fruit flavors are still there, but instead of a sharper-tasting fruit that you might find on a low bush, this is a higher-hanging fruit (literally and figuratively).
Overall: While some of the other brewing methods resulted in great-tasting coffees, the flash method was the only one that really let the beans shine. The chocolate and fruit flavors in the coffees weren't overly powerful like in the cold brews, and the astringency and sourness weren't present at all. Even after warming up for an hour, they still tasted excellent.
After experimenting with these five brewing methods, there was one clear takeaway: if you don't want your cold coffee to taste like a used Goodyear, you need to do more than just pour coffee over ice or throw it in the fridge. The two low-rent methods had terrible results, which is frightening considering the high quality of the beans involved. Lower-quality, pre-ground beans wouldn't stand a chance.
Of the three more-nuanced methods, each had their pros and cons. If you value a stronger cup, either of the overnight cold-brew methods is a better move than the flash-brewed Japanese style. We found that the traditional cold-brew method has subtler, more drinkable results, but hot bloom is the way to go if you're into more intense flavors.
Although both cold-brew methods made great coffee, the flash-brewed Japanese style resulted in a cup that most accurately emulated the characteristics that make hot coffee enjoyable. Since it's less batchable and has a shorter shelf life, this style takes a little more effort, but trust us, you're worth it.
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