I used to pour hot coffee over ice and call it iced coffee. By the time it cooled down, it was brown water. Then I learned the coffee ice cube trick, and that helped — but the real game changer was switching to a completely different brewing method that produces concentrated coffee meant to be diluted.

The coffee ice cube trick (do this regardless)

Pour leftover coffee into an ice cube tray and freeze it. Use those cubes instead of regular ice in your iced coffee. As they melt, they release more coffee instead of water. This fixes the last 20 percent of the dilution problem. It does not fix the first 80 percent — for that, you need to change how you brew.

The method: Japanese-style iced coffee

Instead of brewing hot coffee and cooling it down, you brew directly onto ice. You use half the water as hot water for brewing, and the other half as ice in the carafe. The hot coffee drips onto the ice, flash-chills, and locks in flavors that disappear when coffee cools slowly.

Here is the ratio: for one serving, use 20 grams of coffee, 160 grams of hot water, and 160 grams of ice. That is about a cup of ice in the carafe. Brew the coffee directly onto it. The ice melts instantly from the heat, and what you get is perfectly chilled coffee with zero waiting.

You can do this with a pour-over cone, an AeroPress, or a drip machine with a thermal carafe. Just put the ice in the carafe instead of in your cup.

Cold brew (the overnight method)

If you want the smoothest possible iced coffee with zero bitterness, go with cold brew. Coarse-ground coffee steeped in cold water for 12 to 18 hours. The ratio: one cup of coffee grounds to four cups of cold water. Combine in a jar or French press, stir, cover, and leave on the counter overnight. Strain through a paper filter or fine mesh strainer the next morning.

What you get is a concentrate. Dilute it 50/50 with water or milk over ice. Cold brew concentrate keeps in the fridge for up to two weeks. I make a batch every Sunday and have iced coffee ready in 30 seconds all week.

One more trick: sweeten before you chill

Sugar does not dissolve well in cold liquid. If you like sweetened iced coffee, stir in your sugar or simple syrup while the coffee is still warm, before it hits the ice. Otherwise you get gritty sugar sludge at the bottom of your cup.