How To Make Iced Coffee Out Of Hot Coffee

It’s a hot summer day but you still need your caffeine. Here’s how to turn that pot of freshly brewed joe into cool iced coffee.

Glass of iced coffee on a table

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Last Updated on December 6, 2023

You’ve taken the trouble to brew a pot of coffee. You’d think you’d be happy. Instead, you find yourself wistful for a glass of something cooler. Maybe it’s a hot summer day and you want something cold and icy instead of your normal pot of black, hot coffee. What can you do?

You can make iced coffee from hot coffee, that’s what. We’re here to show you how.

Iced coffee vs. cold brew

First, let’s be clear: Iced coffee is not the same as cold brew. They are both popular kinds of cold coffee, but there are important differences.

Making cold brew is a time-intensive process. Cold brew is more about the method of preparing the coffee than the serving temperature of the coffee itself. (Some people even drink it hot.) For cold brew, you grind beans and steep them at room temperature for an extended period, typically between 12 and 16 hours. This produces a cool pot of coffee with an even, smooth taste.

Cold brew coffee doesn’t come into contact with ice until you drink. It’s brewed cold the whole way through.
Cold brew coffee doesn’t come into contact with ice until you drink. It’s brewed cold the whole way through. (© Katherine Lim | Creative Commons)

Iced coffee is what we’re talking about. You take a hot cuppa and you turn it cold. You can brew the coffee as you normally would, using your favorite brewing method, and then you introduce it to ice via methods described below, to slightly dilute the flavor without eliminating it.

Espresso drinks can be made as iced drinks, too. See our post on cold brew vs. iced Americano, which goes into detail about the differences between these types of beverages.

What are the ingredients in iced coffee?

The essential ingredients in iced coffee are simply brewed coffee and ice. You can add things to iced coffee much the same as you would with regular coffee. Sugar and milk or cream are typical additions. If adding sugar, though, consider adding it to your hot brewed coffee before you cool it because it will dissolve more easily.

So, iced coffee is just hot coffee with ice?

Yes, iced coffee is just hot coffee with ice. That’s the most basic definition, although as mentioned earlier you can certainly dress up iced coffee with sugar, milk or cream, or even flavored syrups.

How do you make hot coffee cold fast?

The best way to cool your hot coffee quickly is to brew it directly onto ice. This is know as flash brewed iced coffee.

Flash brewed iced coffee

Also known as Japanese iced coffee, flash brewed iced coffee involves brewing coffee directly onto ice. The coffee cools immediately, locking up the best aromas and flavors right in the cup.

Flash brewed iced coffee is usually brewed twice as strong as regular hot coffee, which makes it easily enjoyable even after the ice has diluted it.

The Japanese almost always make this type of brew using a pour-over cone.

Making iced coffee from hot coffee

Now that we have that important distinction out of the way, let’s take a closer look at how to turn that hot pot into nice iced coffee.

1. Brew the coffee

Brewing that pot of coffee, or a double shot of espresso, is your first step.
Brewing that pot of coffee, or a double shot of espresso, is your first step. (© Bean Poet)

First, brew a pot of hot coffee.

Follow all the steps necessary for your favorite brew, but make it strong! Use more coffee grounds and/or less water than you typically would. See the section on iced coffee ratio below.

2. Prepare your ice

Don’t skimp on the ice because you’ll need to cool your coffee quickly.
Don’t skimp on the ice because you’ll need to cool your coffee quickly. (© Bean Poet)

Pour between one and two cups of ice into a thick glass or a stainless steel mixing container. A one-pint glass measuring cup or steel milk frothing pitcher will work great.

Set aside some cream or milk, and possibly some syrup or sugar for later.

3. Pour the coffee

Make sure you don’t use a thin glass container, because hot coffee could crack it.
Make sure you don’t use a thin glass container, because hot coffee could crack it. (© Bean Poet)

Pour the hot coffee quickly onto the ice in the mixing vessel. The ice will start to melt, but that’s OK. That’s why you made your coffee extra strong. 

4. Stir

Stir only until the coffee has cooled, and then move on quickly.
Stir only until the coffee has cooled, and then move on quickly. (© Bean Poet)

Stir immediately. The coffee will chill as the ice gradually melts. You want it to cool it as quickly as possible. Keep stirring until the outside of your container is cooler than lukewarm, then move quickly to the next step.

5. Transfer to your drinking mug

It’s always good to have a few new, full-size ice cubes in your drinking mug.
It’s always good to have a few new, full-size ice cubes in your drinking mug. (© Bean Poet)

Stack a few ice cubes into a drinking mug and pour the newly-iced mixture into it, including whatever ice remains.

6. Add dairy and/or sugar

Here’s how it looks with your milk and sugar added. Experiment with cream, too.
Here’s how it looks with your milk and sugar added. Experiment with cream, too. (© Bean Poet)

Add milk or cream, and syrup or sugar. These are optional. You can vary the ratios to your taste. 

Stir well and enjoy.

Iced coffee ratio

The ideal coffee-to-water ratio when brewing for iced coffee is 1-to-12, or one part coffee to 12 parts water (by weight). This is considerably stronger than our recommended brew ratio for regular coffee, which is 1-to-17. We recommend it because cooling hot coffee with ice inevitably results in dilution of the coffee as the ice melts.

Stronger brewing methods for iced coffee

You can vary your recipe depending on your equipment. Nespresso, moka pots and AeroPress are all capable of making a nice strong coffee that will hold up even after the ice and cream are added. The most important thing, regardless of your brewing method, is that you pour and ice the coffee fast.

By following these quick and easy steps you can turn your hot coffee into iced coffee on a hot summer’s day and enjoy a cafe-style beverage of your own making.

Iced coffee vs. hot coffee

The most obvious difference between iced coffee and hot coffee will always be the temperature, but there are a few other things you may notice if you try a taste test.

Iced coffee can be watery. We always try to brew the coffee strong enough to account for the dilution that’s coming when ice is added, but it can be tricky to get right. Slightly watery iced coffee is a common thing, especially if you haven’t practiced making it very much.

Iced coffee can taste bitter. Even though it’s the same coffee that you brewed hot, iced coffee sometimes seems to carry a slightly bitter taste. We don’t think this is really bitterness, but rather the absence of that nice acidity that comes out when coffee is served hot.

As for the caffeine and antioxidants, they should be comparable whether you’re drinking your coffee iced or hot. The differences arise only with cold brew, which tends to decrease the antioxidants but increase the concentration of caffeine.

Tips for making better iced coffee

Even if you’re not normally a fan of milk or dairy products in your coffee, you might want to make an exception for your iced coffee. Allowing coffee to cool before drinking it gives it a level of bitterness that it doesn’t have when it’s hot. We find that the addition of a little milk can add just enough fatty flavor to offset the bitterness. It’s quite nice.

After that, the biggest culprit in most subpar iced coffee is the excess water.

How do you make iced coffee from hot coffee without watering it down?

We can share three great ways to make iced coffee from hot coffee without watering it down.

1. Make it stronger

Brew your coffee with a much higher ratio of coffee to water than you normally would. By cutting out a portion of water during the brewing process, you allow for that water to be replenished by melting ice during the cooling process. The end result is coffee that comes out at approximately the same ratio that it would have if you had just brewed it normally.

2. Let the coffee cool first

This is a simple solution, but it won’t work if you’re in a rush. You can cool the coffee for a couple of hours in the refrigerator, and you’ll get very little dilution when you add ice cubes at that point. Even letting the coffee cool for 20 minutes on the counter before you add the ice can make a big difference. The ice melts much more slowly and causes less dilution.

3. Coffee ice cubes

We love this solution. If you become a frequent iced coffee drinker, keep an ice cube tray of coffee ice cubes in your freezer. Fill it up with hot coffee once a week. Then, when you’re ready for some iced coffee, you can brew right on top of those cubes and you’ll have great flash-brewed coffee without any watering down at all.

Iced coffee makers

Several familiar coffee and kitchenware brands sell dedicated iced coffee makers. These work just fine for making iced coffee, but don’t let their names fool you—they aren’t doing anything that you couldn’t do at home with your existing coffee-brewing equipment.

Here is one example from Mr. Coffee:

It’s essentially just a regular, single-serve coffee maker that brews like any other. The ‘innovation’ is including a tall plastic cup with a straw for you to put your ice in before brewing. Some brands will mark the appropriate ice level on this cup to guide you.

Honestly, we think you could figure this all out using your existing coffee maker, and then you wouldn’t be limited to a single-cup serving.

Iced coffee FAQ

How hot is coffee?

Hot coffee is typically served between 160 F and 185 F. It is ideally brewed between 195 F and 205 F, so there is usually some natural cooling that occurs between brewing and serving. If you flash brew your iced coffee, you’ll be starting the cooling process from at least 195 F.

How do you cool down hot coffee for iced coffee?

Ice cubes directly in the coffee are the best way to cool down hot coffee for iced coffee. But they aren’t the only way, as we explain below.

Can you put hot coffee in the fridge to make iced coffee?

Cooling hot coffee in the fridge is a perfectly acceptable way to make iced coffee. Keep in mind that this may take an hour or two, so you will lose some of your coffee’s freshness while you wait for it to cool. And if you want it really iced, you’ll still want to toss some ice cubes in at the end.

If you intend to mix in sugar or milk, consider doing that before it goes into the fridge. It will dissolve more easily when the coffee is still hot.

Can I used leftover coffee for iced coffee?

You can use leftover coffee for iced coffee, and this is a common practice among many restaurants and diners. We don’t recommend it, for the simple reason that you will essentially be drinking stale coffee. We like our coffee fresh! It won’t hurt you, but it is an inferior drink.

Can you drink day old coffee?

Yes, you can drink day old coffee that has been cooled overnight for iced coffee. You may even be served it when you order iced coffee in a restaurant. But it’s not ideal. Coffee begins to slowly decline in quality as soon as it’s brewed. If it’s been sitting for a day, it is quite stale. Not harmful, just lifeless.

There once was a coffee so hot,
Which on summer days mattered a lot.
When ice came to play,
It cooled in a way,
That made it the best of the lot.

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