Coffee is one of the most popular beverages in the world, with over 2.25 billion cups consumed per day. Many factors go into brewing a great cup of coffee, from the bean variety and roast, to the grind size and brewing method. One factor that is often overlooked is the temperature of the water used for brewing. While most people use hot or boiling water out of habit, there are some compelling reasons why using cold water can actually result in a better tasting cup of coffee.
What happens when you use cold water to brew coffee?
Brewing coffee with cold water, ideally around 200F to 205F, results in lower extraction from the coffee grounds compared to hotter water. This means that less caffeine and fewer bitter, acidic compounds are extracted into the final brew. Here’s a closer look at the science behind cold brew coffee:
Slows down extraction
Colder water doesn’t extract as efficiently as hot water. Compounds in coffee beans dissolve faster in hot water, so colder water results in a slower brewing process. This gives the barista or coffee drinker more control over extraction.
Extracts different flavors
Hot water tends to extract more bitter, harsh tasting compounds. Colder water extracts more floral, fruity notes that are typically masked by the bitter notes in hot coffee. Cold brews tend to taste sweeter and fruitier.
Results in lower acidity
Cold brew coffees are up to 70% less acidic than hot coffee. Acidity is desirable up to a point, but lower acidity makes cold brew easier to drink black and easier on sensitive stomachs.
Reduces oils and fats
The colder water also extracts fewer oils and fats from the coffee beans, meaning the final product has a cleaner mouthfeel. The lack of oil also means cold brew coffee has a longer shelf life compared to hot coffee.
Other benefits of using cold water
Aside from changing the extraction and flavor profile, using cold water has other benefits:
Easier preparation
With hot coffee, it’s important to precisely control water temperature for optimal extraction. Cold water requires less precision, making preparation easier. Simply mix the coffee grounds and water and let steep for 12-24 hours.
No need for fancy equipment
Cold brew can be made with just a mason jar or other common kitchen tools. No need for kettles, pour over cones, French presses, or other expensive brewing gear. All that’s required is a way to filter the coffee after steeping.
Better coffee concentrate
The cold extraction makes cold brew an excellent coffee concentrate. Simply dilute with water or milk over ice for cold coffee drinks. The concentrate stores well in the fridge for weeks.
Lower caffeine content
The cold water extracts less caffeine from the beans compared to hot water. Cold brew contains about 30-50% less caffeine per serving compared to hot coffee.
Easier on your stomach
Thanks to the lower acidity and slower extraction, cold brew tends to cause less stomach irritation or discomfort compared to regular iced coffee or hot coffee in those prone to digestive issues.
Ideal water temperature for cold brew
The “ideal” temperature range can vary based on factors like brew time, grind size, bean variety, and filtration method. However, most coffee experts recommend using water between 200F and 205F to brew cold coffee concentrate. Key considerations:
Water straight from the tap is too warm
Tap water is usually 110F to 120F, too warm for proper cold brew. Use chilled water instead.
Some extraction is needed
Water that is too cold, like straight from the fridge 40F water, will extract even more slowly and result in weak, under-extracted coffee.
The 200F – 205F goldilocks zone
Water at 200-205F allows for extraction of sweeter, fruitier flavors while limiting bitterness and acidity. For most cold brew methods, this results in optimum flavor.
Room temperature works too
If precise temperature measurement isn’t practical, room temperature water 68F-72F can work too. The extraction will be slower, so allow for a longer brew time.
| Water Temperature | Resulting Flavor |
|---|---|
| Around 205F | Balanced, optimum extraction |
| 120F or hotter | Over-extracted, bitter, acidic |
| 40F or colder | Under-extracted, weak flavor |
How to brew cold coffee
Now that we’ve covered why you should use cold water, let’s look at some cold brew methods to try at home:
Cold brew mason jar
Add coarse ground coffee and cold water to a quart-sized mason jar. Let steep at room temperature or in the fridge for 12-24 hours. Strain through a coffee filter.
Cold drip tower
Water drips slowly through coffee grounds into a carafe. Produces a delicate, tea-like concentrate. Requires special equipment.
Immersion brew
Coarse ground coffee is fully immersed in cold water for an extended period then filtered. Larger batches are possible.
Japanese-style slow drip
A hybrid of cold drip and immersion brewing. Water is added slowly over coffee grounds over 6+ hours then filtered.
Cold press
Ground coffee is steeped in a French Press or other vessel then pushed through a fine mesh filter. No electricity required.
Toddy cold brew system
Commercial-grade cold brew system using a mix of countercurrent and immersion techniques. Produces consistent results.
Cold brew coffee ratio
The recommended coffee-to-water ratio for cold brew is between 1:4 to 1:8 (1 part ground coffee for every 4 to 8 parts water, by weight). Here are some tips:
Start with a 1:4 or 1:5 ratio
Use 1 part ground coffee to 4 or 5 parts cold water. This produces a concentrate for diluting later. Add more water upon serving.
Go coarser at higher ratios
At ratios above 1:5, use a coarser grind size like sea salt or sugar. This prevents over-extraction.
Stronger flavor? Use less water
For bolder cold brew, use ratios like 1:3 or 1:4. Shorten the brew time to avoid over-extracting.
Weaker flavor? Use more water
For milder cold brew, use ratios from 1:6 to 1:8. Extend brewing time to extract fully.
Experiment to get your desired strength
There’s no single perfect ratio. Try different coffee-to-water ratios and brew times to dial in your preferred strength.
| Ratio | Flavor | Notes |
|---|---|---|
| 1:3 | Very strong | Lower water amount, shortest brew time |
| 1:4 to 1:5 | Strong concentrate | Standard for concentrating |
| 1:6 to 1:8 | Mild strength | Higher water amount, longer brew time |
Should you use tap, filtered, or bottled water?
The type of water used affects the taste of the final brew. Here’s a comparison:
Tap water
– Convenient and cheap
– May contain off-flavors like chlorine
– Minerals can make coffee taste unbalanced
Filtered water
– Removes chlorine and sediment
– Leaves beneficial minerals
– Allows true coffee flavor to shine
Bottled water
– Consistent results from batch to batch
– Lacks important minerals for extraction
– Adds to plastic waste
For the best tasting cold brew, filtered water is ideal. It removes sediment and off-flavors while leaving just the right mineral content to properly extract coffee solids. Tap water can work fine, just let it de-gas for a few minutes first. Avoid using distilled or purified water, as the complete lack of minerals makes it unsuitable for brewing.
Grind size for cold brew
Use a coarse grind for all cold brew methods. A fine grind over-extracts at cold temperatures. Aim for a sea salt or granulated sugar consistency. Cold water can’t penetrate dense clumps, so make sure the grounds are freshly ground with few fines. Here are ideal grind sizes for various brew methods:
Immersion cold brew
– Coarse grind
– Enables controlled extraction
– Achieves optimum flavor
Cold drip brewers
– Extra coarse grind
– Allows for slow drip filtering
– Prevents clogging or overflow
Cold press
– Medium coarse grind
– Finer than other methods
– Lets grounds form a filter “cake”
Regardless of method, avoid a powdery grind size. The increased surface area will over-extract. Dial in your grind and brew time to achieve your preferred strength.
How long to brew cold coffee?
Cold brew requires much longer brewing times than hot coffee to properly extract flavor from the grounds. Brew time can range from 4 hours to 24 hours depending on factors like grind size and coffee-to-water ratio.
12-18 hours
This is the most common timeframe for immersion cold brewing. Allow for a coarse grind.
18-24 hours
For a lighter ratio like 1:8, aim for 18-24 hours to extract fully with a coarse grind.
4-12 hours
A 1:4 ratio with a fine grind can extract fully at the lower end of this range.
24+ hours
Possible for very diluted ratios like 1:10 or cold drip towers. Ensure coffee doesn’t extract too far.
As a starting point, try steeping for 16-18 hours. Taste periodically and adjust time up or down to suit your preferences. Bottled cold brew is typically brewed for 12-36 hours.
Does cold brew taste different than iced coffee?
Cold brew and iced coffee are similar, but have some distinct differences in flavor:
Less acidic and bitter
The cold extraction creates a naturally sweeter flavor with lower acidity.
Smoother mouthfeel
Since cold brew contains less oils, it has a cleaner aftertaste.
Tea-like
Some cold brews have subtle tea flavors due to the extended brew time.
Fruity, floral
The cold water extracts different aromatic compounds.
Chocolate, caramel notes
The slower brewing can bring out more chocolaty undertones.
Overall, cold brew tends to be more mellow and nuanced compared to regular iced coffee. Try it if you want a refreshing coffee drink that’s lower in acid.
Should you refrigerate cold brew?
After brewing, cold brew coffee concentrate should always be stored in the refrigerator. Proper storage preserves freshness and prevents spoilage.
Keeps it cold
The fridge keeps finished cold brew chilled for serving over ice.
Retains flavor
Refrigeration delays staling and oxidation, preserving taste.
Inhibits microbial growth
The cold fridge temperatures inhibit mold and bacteria growth.
Allows storage
Concentrate keeps 1-2 weeks in the fridge.
The exceptions would be right before serving or if bringing to room temperature to add hot water or milk. Otherwise, transfer the finished brew to a sealed container in the fridge immediately after filtering.
Does cold brew go bad?
Like any beverage, cold brew coffee has a limited shelf life:
Lasts 1-2 weeks refrigerated
Sealed cold brew concentrate keeps fresh-tasting for up to 2 weeks in the fridge.
Can last 24 hours unrefrigerated
Brief room temperature storage is OK, but flavor deteriorates quicker.
Watch for off-flavors
Discard if bitter, overly acidic, or funky tasting.
Don’t drink spoiled cold brew
Toss if thick, slimy, or growing mold. Can make you sick.
For maximum freshness and food safety, discard any leftovers after 1-2 weeks. If storing for shorter periods near room temperature, look for changes in appearance, aroma, and taste.
Is cold brew stronger than iced coffee?
Due to differences in how it’s made, cold brew generally contains more caffeine and tastes stronger than regular iced coffee:
Higher coffee-to-water ratio
Cold brew uses more ground coffee per ounce of water.
Longer brew time
The extended brew time extracts more caffeine.
Higher total dissolved solids
More coffee solids make it into each serving.
Less dilution
It’s typically served black or with minimal milk/cream.
However, since cold brew is often served as a concentrate, the prepared cups may have less caffeine if heavily diluted with water or ice.
Conclusion
Using cold or room temperature water when brewing coffee may seem odd, but the lower temperatures actually enable better control over the extraction and flavor. Cold brew is gentler tasting, naturally sweeter, and less acidic than conventional hot coffee. While it requires more advance planning, the simplicity of preparation and unique flavor profile make cold-extracted coffee worth trying. Follow the guidance in this article on factors like ideal water temperature, coffee-to-water ratio, grind size, and steep time to experience the best tasting cold brew possible.