What Happens When We Drink Coffee With Cold Water?

November 24, 2025 •

4 min read

According to the Specialty Coffee Association, cold brewed coffee is perceived as significantly less bitter and acidic than hot brewed coffee, even when chemical acidity levels are similar. So, what happens when we drink coffee with cold water? The answer lies in the slow, low-temperature extraction process that creates a uniquely smooth and less bitter beverage.

Quick Summary

Drinking coffee prepared with cold water, known as cold brew, results in a less acidic and smoother beverage due to a slow, gentle extraction process. This method produces a robust, less bitter concentrate that can be easier on the stomach than hot coffee.

Key Points

Less Acidity: Brewing coffee with cold water (cold brewing) produces a less acidic beverage, which is gentler on the stomach and a good choice for those with acid reflux.
Smoother Flavor: The slow, cold-water extraction process draws out fewer bitter compounds, resulting in a coffee that is naturally sweeter and smoother than hot-brewed coffee.
Different Extraction: Unlike iced coffee, which is cooled hot brew, cold brew is steeped entirely in cold water for an extended period, creating a distinct chemical composition and flavor profile.
Comparable Caffeine: While cold brew concentrate is high in caffeine, the final diluted drink has a caffeine content comparable to a standard hot cup of coffee.
Digestive Comfort: The lower acidity and unique extraction of cold brew can reduce stomach irritation, making it a more comfortable option for sensitive individuals.
Easy to Make Ahead: Cold brew can be prepared in a large batch and stored in the refrigerator for up to two weeks, saving time on daily coffee preparation.

The Science of Cold Extraction

When you use cold water to make coffee, you're not just creating a cold version of a hot drink; you're triggering an entirely different chemical process. In traditional hot brewing, the high temperature rapidly pulls soluble compounds, including oils and acids, from the coffee grounds. This quick extraction is responsible for the intense aromas and flavors, but it also releases bitter and harsh-tasting compounds that can be tough on the stomach.

Cold brewing, by contrast, relies on a long steeping time—typically 12 to 24 hours—to slowly and gently draw flavor from the grounds. Since cold water is less efficient at dissolving solids, it extracts a different set of compounds. It pulls desirable flavors while leaving behind many of the bitter acids and oils that heat would otherwise extract. The result is a concentrate with a different chemical makeup, and consequently, a distinct flavor profile.

Flavor and Acidity: The Smooth Advantage

The most noticeable result of drinking coffee with cold water is the taste. The low-and-slow extraction process is the key to creating a brew that is far less bitter and more naturally sweet than hot coffee. This flavor profile allows the subtle notes of the coffee beans, such as fruity or chocolatey undertones, to shine through without being masked by bitterness.

Another significant benefit is the reduced acidity. Cold brew coffee has been measured at a higher pH than hot coffee, making it significantly less acidic. For individuals with sensitive stomachs or acid reflux, this can be a game-changer. The lower acidity can reduce the digestive discomfort often associated with traditional coffee consumption, making it a gentler and more tolerable option.

Health Effects: Digestion and Beyond

Beyond its digestive benefits, drinking coffee with cold water offers other health advantages. Since the cold brew process leaves fewer compounds to irritate the digestive system, it’s a popular alternative for those who experience heartburn or indigestion. In terms of antioxidants, cold brew contains powerful compounds like chlorogenic acid that help protect the body from cell damage and inflammation, similar to its hot counterpart. Some studies even suggest that the specific extraction method might preserve certain antioxidants more effectively.

Furthermore, the caffeine content of cold brew concentrate is high, though it's typically diluted, making the final beverage's caffeine level comparable to a regular cup of hot coffee. The caffeine can help boost metabolism and improve mood and cognitive function, providing a sustained energy lift without the jitters sometimes caused by the rapid absorption of hot coffee.

How to Make Your Own Cold Brew

Making your own cold brew is a straightforward, hands-off process. Here’s a simple guide:

Grind your beans: Use a coarse grind, similar to cornmeal. A coarse grind prevents over-extraction during the long steeping process.
Combine and steep: Mix coarsely ground coffee with cold, filtered water in a large jar. A common ratio is 1 cup of grounds to 4 cups of water. Stir gently to ensure all grounds are saturated.
Wait: Cover the container and let it steep in the refrigerator for 12 to 24 hours. The longer you steep, the stronger the concentrate will be.
Strain: After steeping, strain the mixture through a cheesecloth or fine-mesh sieve. Some people strain twice for a smoother result.
Serve: Dilute the cold brew concentrate with water or milk at a 1:1 ratio, and serve over ice. Store the remaining concentrate in the fridge for up to two weeks.

Instant Coffee and Cold Water

If you need a quick caffeine fix, you can also use cold water with instant coffee. While it lacks the complex flavor profile of a proper cold brew, instant coffee powder or granules will dissolve in cold water with some stirring. This is ideal for those who prioritize convenience over the nuanced flavors of a slow-steeped brew. Some experts even claim that starting with cold water helps preserve some of the instant coffee's subtle flavor notes.

Cold Brew vs. Iced Coffee: A Key Difference

It's important to distinguish between cold brew and iced coffee, as they are not the same thing. Iced coffee is simply hot coffee that has been brewed normally and then cooled down, usually by pouring it over ice. Cold brew, on the other hand, is coffee that is specifically brewed using cold water from the start. This fundamental difference in preparation is what accounts for their different flavor profiles and acidity levels.


Criteria	Cold Brew	Iced Coffee (Hot Brew)
Acidity Level	Significantly lower, making it gentler on the stomach.	Higher, retaining the acidity of a standard brew.
Flavor Profile	Smooth, naturally sweet, less bitter, with subtle flavors preserved.	More robust, with a sharper, sometimes bitter flavor profile.
Brewing Time	12-24 hours of steeping.	A few minutes to brew hot coffee.
Caffeine	Often high in concentrate, diluted to a comparable level to hot coffee.	Standard caffeine content, comparable to a hot cup.
Preparation	Requires advanced planning and a long, slow steeping process.	Quick and easy to make on demand by cooling hot coffee.

Conclusion: Is Cold Water Coffee Right for You?

For those who find hot coffee's bitterness or acidity off-putting, a cold brew made with cold water presents a fantastic alternative. The gentle, slow extraction process produces a beverage that is naturally smoother, less bitter, and easier on the stomach. The convenience of preparing a batch in advance for a week of easy, pre-made coffee is another major benefit. While instant coffee can be made quickly with cold water, it's the true cold brew that delivers the most significant difference in flavor and acidity. Ultimately, the best method depends on your personal preferences for taste, convenience, and digestive comfort. By understanding what happens when we drink coffee with cold water, you can choose the brewing method that best fits your lifestyle and palate.

For more in-depth information on the health benefits of cold brew, you can explore resources like the comprehensive article on Healthline.

Frequently Asked Questions

Yes, it tastes significantly different. Coffee brewed with cold water (cold brew) has a smoother, less bitter, and often sweeter flavor profile compared to hot-brewed coffee, as the cold extraction process pulls out different compounds from the coffee grounds.

For many people, yes. Cold brew coffee is less acidic than hot coffee, which can lead to less stomach irritation and is often a better option for those who experience heartburn or acid reflux after drinking regular coffee.

Yes, instant coffee can be mixed with cold water. It may take a little longer to dissolve completely compared to hot water, but it is a perfectly acceptable way to prepare it for a quick, cold coffee.

The caffeine content can vary. Cold brew is typically made as a concentrate with a high coffee-to-water ratio. When diluted for drinking, the final caffeine level is generally comparable to regular hot coffee, though it can still be slightly higher.

The brewing process for cold brew takes much longer than hot coffee, typically requiring 12 to 24 hours of steeping in the refrigerator or at room temperature.

While you can use any beans, coarsely ground medium-to-dark roast coffee is often recommended for cold brew. The coarser grind prevents over-extraction, and the roast provides a balanced flavor.

For most people, there are no significant disadvantages. Some studies indicate that hot coffee may contain slightly more antioxidants, but cold brew still offers similar health benefits like a potential boost to metabolism and cognitive function.