Does Adding Water To Coffee Reduce Caffeine?

Has your morning “pick-me-up” ever turned into the jitters after a too-strong cup of coffee? Coffee jitters are caused by too much caffeine, a stimulant that blocks your receptors responsible for drowsiness. Can adding water to coffee reduce caffeine and keep the jitter at bay?

Adding water to already brewed coffee does not reduce caffeine. Additional water will dilute the coffee, providing less caffeine per ounce. Still, it won’t impact the overall caffeine in the cup. Reduce caffeine by using darker roasts, less or coarser grounds, or switching to cold brew or decaf.

We will discuss why adding water to coffee does not reduce caffeine. But more importantly, how to limit caffeine intake, be it for a milder caffeine experience or health reasons.  

Does Adding Water To Coffee Reduce Caffeine?

Additional water does not reduce caffeine in coffee.

Adding additional water to your cup of coffee dilutes the caffeine. Still, it has zero effect on the overall caffeine content. Instead, you will simply have less caffeine per sip.

You can add fewer coffee grounds to your morning brew to reduce the amount of caffeine. However, adding more water to already-brewed coffee won’t reduce the caffeine. So, yes, you will have less caffeine when compared to an ounce by ounce, but your cup of coffee already contains the entire dose of caffeine.

Can You Reduce Caffeine In Coffee?

While extra water won’t have any effect on reducing caffeine in coffee, several straightforward methods can help naturally reduce the caffeine content.

Switch To A Darker Roast (Arabica)

Switching to a darker roast like Arabica instead of Robusta beans can help reduce your morning coffee’s caffeine content.

It might sound counterintuitive, but despite the rich flavor of darker roasts, they contain less caffeine than light coffee roasts. Light roasts can have up to double the caffeine content.  

Arabica Coffee Beans vs. Robusta Coffee Beans

Arabica coffee beans are at the top of the popularity list, equating to over 60% of coffee drank. This darker roast variety typically has about 1.5% caffeine.

Arabica typically has a higher acidity and softer, sweeter flavor, with notes of nuts, chocolate, fruit, and berries. It also ranges in a higher price spectrum.

In comparison, Robusta coffee beans are light-roast African coffee beans. Although less expensive, they contain up to 2.7% caffeine content.

Like its name, Robusta coffee beans generally boast a more robust, more intense, bitter-tasting cup of coffee with grain-like and rubbery overtones.

Use Coarser Coffee Grounds

Your coffee beans’ grind size impacts the amount of dissolving soluble material during the brew time.

The finer the coffee grounds, the larger the surface area and the faster the coffee and caffeine are extracted. This results in a more robust, highly caffeinated cup of coffee.

A slightly coarser grind will help reduce the extraction speed and caffeine content. However, avoid grinding the beans too coarsely as it may result in under-extraction and a bitter and sour-tasting brew.

Downscale On The Coffee Grounds

You can add fewer coffee grounds to your morning brew to enjoy a cup of coffee with less caffeine.

The golden brew ratio is generally 1:18, which consists of 1 part coffee and 18 parts water. Use a greater ratio to produce a lighter, less concentrated brew.

Reducing the coffee grounds in your brew will reduce the caffeine and result in a weaker-tasting cup of joe.

Note that adding more water to an already-brewed cup of coffee will only increase the volume of the drink. It won’t reduce the caffeine content.

Reduce The Brewing Time

You can reduce the brewing time for a less-potent cup of coffee.

The longer you brew coffee, the more concentrated the caffeine levels will be in your cup of joe. For example, brewing coffee grounds in water for five minutes will naturally extract more caffeine and produce a stronger cup of coffee than grounds brewed for three minutes.

Over-reducing the brewing time can result in an under-extracted, sour brew. So, reduce your usual brewing time by 10 to 20% for a less caffeinated cup of coffee.

Switch To Cold Brew Coffee

Cold brew is a drink made by brewing ground coffee with cold or room-temperature water for 12 to 18 hours, sometimes longer. Then, the grounds are strained, chilled, and diluted with milk, water, or cream or served over ice.

At cooler temperatures, the caffeine is extracted from the coffee grounds slower. So, despite using more coffee beans, cold brew cold brews contain up to 30% less caffeine.

Cold brew aficionados mention that cold brew coffee tastes milder and smoother and lacks the sharp acidity of ordinary brewed coffee. Who knows, it may become your new favorite summer drink.

Sip On A Smaller Serving Size

A giant cup of coffee sounds tempting, especially after a light night. However, drinking smaller cups of coffee helps to limit your caffeine intake. 

According to the FDA, an average healthy adult should limit their caffeine intake to approximately 400mg daily, which is 4 to 5 cups of coffee. An average 8oz cup of black coffee contains around 70 to 140 mg of caffeine. A 1oz shot of espresso contains 40 to 63mg of caffeine, less than half the caffeine content.

Switch to smaller cups of coffee to keep your caffeine intake moderate. 

Switch To Decaf

If all else fails, switch to decaf. Decaf coffee undergoes a process of first removing the caffeine from the coffee beans. The beans are then roasted and brewed into a delicious cup of coffee – without the kick, obviously.

Decaf coffee isn’t completely caffeine-free. An 8oz cup of decaf coffee contains around 2mg of caffeine compared to 70 to 140 mg in regular coffee.

You can also mix half and half of decaf and regular beans if you aren’t convinced about drinking full-blown decaf. This will ensure coffee with less caffeine and zero compromises on taste.


Adding water to already-brewed coffee does not reduce the caffeine content. So, if you love coffee but hate the jitters, consider testing darker Arabica roasts, playing around with the coarseness of coffee grounds, changing your brewing method, or switching to decaf.

Either way, happy caffeinating!


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