Can You Heat Up Cold Brew Coffee?
Cold brew coffee is prepared by steeping ground coffee in room temperature water or cold water for 12-24 hours. The AeroPress provides the quickest way to make cold brew coffee in a process that takes less than three minutes.
Despite the numerous advantages of cold brew coffee, some cold coffee lovers prefer to brew their coffee hot and cool it rapidly with ice. But what happens when you want a hot drink from a cold brew?
Can you heat up cold brew coffee?
Yes, you can heat up cold brew coffee and, although the flavor will change, with a few tips you can yield a heated cold brew that tastes nearly as good as before. Cold-brew coffee can be a concentrate or ready to drink.
Cold brew coffee is hailed for its smoothness, natural sweetness, and lack of bitterness and is recommended for coffee beginners who may be put off by the inherent bitterness that is more pronounced in hot coffee.
Dark roast cold brew coffee is less acidic and rich with chocolatey notes. When heating up cold brew coffee, avoid extending the heating period or boiling the coffee as it can lead to sour flavors due to the breakdown of the volatile flavor and aroma compounds.
If the cold brew coffee is in the fridge, you can heat it up immediately without prewarming to room temperature.
You may want to consume the warmed cold brew and avoid storing it as the more you expose and change the temperature of the cold brew coffee the more you interfere with the volatile compounds hence reducing its freshness.
4 Ways to Heat up Your Cold Brew Coffee
Usually, cold brew is prepared as a concentrate and then diluted to drink. However, some people prefer to make a cold brew that is ready to drink. Store-bought cold brews are also available as concentrates as well as ready-to-drink.
Cold brew concentrate is highly caffeinated per fluid ounce. Here are the four ways to heat up cold brew coffee
1. Heating Cold Brew Coffee on the Stove
- Add cold brew coffee in a saucepan and heat it on medium heat on a stove
- Continue heating until the coffee has reached a drinkable temperature. Avoid boiling the coffee as it will break down the volatile compounds and the coffee will be more sour or bitter
2. Adding Hot Water to Cold Brew Concentrate (How to Make Hot Cold-Brew Coffee)
Adding hot water will dilute and warm the cold brew coffee concentrate to the desired strength and temperature respectively. The coffee is smoother and with natural sweetness.
- Heat hot water on a stove or kettle
- Preheat a mug by rinsing with hot water
- Add cold coffee concentrate to about a third of the mug
- Add hot water to fill the mug. You may adjust the ratio to your preferred strength
You can also add hot milk or frothed milk to the cold brew concentrate for a richer flavor. Milk substitutes such as creamer and heavy cream also go well with cold brew coffee.
3. Microwaving Cold-Brew Coffee
- Add the cold brew to a microwave-safe mug and place it in the microwave
- Turn the microwave on to medium heat to avoid rapid heating that can scorch the coffee and degrade its chemical composition
- Heat the coffee in intervals of 10-20 seconds until the desired temperature is achieved. 2-3 intervals will do the trick for a regular sized mug of coffee
4. Double-Boiler Method
This method takes time and is probably not worth the trouble but some coffee snobs will not heat coffee any other way. Most of them will not even consider heating cold-brew coffee.
The slow heating in a double-boiler can reduce the breakdown of flavor compounds unlike applying direct heat to the coffee
- Add water to a medium-sized saucepan to just below the halfway line and warm it on a stove on medium heat
- Rinse a mug with hot water to preheat it
- Add cold brew coffee to the mug and immerse the mug in the hot water and bring the water to a boil
- Turn the stove off and leave the coffee mug in the saucepan to continue heating to the desired temperature
- Use a towel to remove the mug from the saucepan without scalding your hands. Enjoy the hot-cold brew coffee
Can You Heat Up Frozen Cold Brew Coffee?
You can heat up frozen cold brew coffee by dunking the cold brew ice cubes in warm water or hot coffee. Adding ice cubes of cold brew concentrate in warm water will yield a ready-to-drink coffee.
Alternatively, you can thaw the frozen cold brew coffee by leaving it outside the fridge overnight and then heat it on a stove or in a microwave.
You would be prudent to avoid heating frozen coffee right from its frozen state as some parts of the coffee will melt faster than others leading to temperature disparities that cause some of the coffee to boil while the other parts are still warming.
Does Microwaving Coffee Change The Taste?
Any time you reheat coffee, you lose some of the flavors, and microwaving is not an exception. In fact, microwaving coffee poses more risks to the taste of your coffee because
- Foreign aromas and flavors. We heat up all kinds of food in the microwave, and some foods including fish, bacon, and pizza leave their aromas in the microwave. Coffee absorbs the lingering odors in the microwave and ends up smelling and tasting like food or worse. You are better off heating up the cold brew on a stove if the microwave has some residual food odors
- Duration. Microwaving coffee for a long duration (more than 30 seconds at a time) accelerates the break down of flavors and aroma and the coffee will taste burnt. Instead, microwave the coffee in 2-3 short intervals of 10-20 seconds and avoid overheating
- The vessel that you use to microwave coffee. Some containers can leach their flavors into the coffee when microwaving. You are better off microwaving your coffee in microwave-safe ceramic or glass containers as they are neutral
Does Heating Up Cold Brew Coffee Make It Acidic?
No, the acidity is pulled from the ground coffee when brewing the cold brew coffee and acid compounds do not break down when you heat the coffee.
However, your tongue may perceive the acidity or sourness when you drink a heated cold cold brew due to the chemical changes when heating as compared to a regular cold brew. Some coffee flavors may also become alive when you heat the cold brew.
Is Cold Brew Coffee Less Acidic Than Hot Brew?
Coffee enthusiasts, especially, cold brew aficionados swear by the low acidity of cold brew coffee with some suggesting that cold brew has nearly half the acidity in hot coffee. There are also numerous blogs recommending cold brew coffee for people with GERD problems.
However, there is no scientific evidence to back these claims and we advise people with acid reflux problems to consult their physicians before indulging in coffee.
On the contrary, an authoritative scientific study has proven that the acidity of cold brew coffee is nearly similar to that of hot coffee with pH values ranging between 4.85 and 5.13.
The study sampled six types of coffee beans from five different countries and compared the acidity of cold brew coffee and hot coffee brewed from the same beans. The table below shows that the difference between the pH of cold brew and hot brew coffee is negligible.
| Coffee Origin | Hot Brew pH | Cold Brew pH |
|---|---|---|
| Brazil | 5.10 | 5.04 |
| Ethiopia (Yardi) | 4.85 | 5.01 |
| Ethiopia (Yirgzi) | 4.96 | 4.96 |
| Myanmar | 4.92 | 5.13 |
| Colombia | 4.99 | 5.0 |
| Mexico | 4.95 | 5.08 |
The study also found that although the pH of cold brew and hot coffee is comparable, hot brew coffee has a higher concentration of acidic compounds due to the presence of more titratable acids than in cold brew coffee.
You may ask if cold brew has a comparable acidity to hot coffee, why is cold brew smoother than hot brewed coffee? A different study concluded that there is no correlation between the pH of coffee and the perceived acidity in the taste of the coffee.
The study also reported that most of the extractable chlorogenic acid (CGA) was pulled at steeping times of around 400 minutes.
Key Points to Remember when Heating Cold Brew Coffee
- Heat only the amount of cold brew that you intend to consume to safeguard the aroma and flavors
- Avoid extended heating times as it’s a sure way of breaking down most of the volatile compounds. The resulting drink can be very astringent
- Avoid boiling the cold brew coffee when heating. Ideally, you should warm the cold brew to a drinkable temperature as the more you heat it the more the coffee loses its flavor and aroma compounds
- Avoid leftovers from the heated cold brew as it has lost most of its desirable qualities. You may want to discard it or freeze the leftover coffee into coffee ice cubes that you can add to cold coffee in the future
- When microwaving coffee, the odor in the microwave, the duration, and the container that you use will impact the aroma and flavor of the coffee
