Ideal Coffee to Water Ratio – Bun Brewing Basics

As much as we like to imagine that achieving the perfect cup of coffee starts and ends when you click the order button with Bun Coffee, we know that there is more to the equation.

Achieving the perfect brew comes down to more than just the quality of the beans; it’s about how they are brewed. In this simple guide, we’ll look at the perfect coffee-to-water ratio when brewing coffee, how you can achieve a consistent brewing outcome, and the variables that you need to control for the ideal espresso, filter, pour over – or however else you choose to make your coffee.  

Table of Contents

Understanding Coffee to Water Ratio

Coffee to water ratio, or your brew ratio, refers to the amount of coffee and water that is used when making your brew. Irrespective of whether you’re making espresso, pour-over, French press, AeroPress, or whatever else – the principles for brew ratio apply.

The ratio of water to coffee is determined by weight and helps to ensure a consistent cup of coffee. A brew ratio affects the strength of the coffee, with a lower ratio (higher water to coffee) producing a less concentrated, lighter brew than a higher coffee-to-water ratio.

Why Coffee to Water Ratio Is Important

 Coffee to water ratio is one of the most important factors in achieving consistency – particularly in commercial environments where patrons expect consistency in each cup of coffee.

Brew ratio influences the coffee strength, the flavour, and the mouthfeel in each cup of coffee that we make. Ratios can drastically change the way that coffee tastes and how it is enjoyed, so it’s important to properly understand the golden ratio for your chosen brewing method.

The Golden Brew Ratio

 So, what is the ideal brew ratio, and how can you achieve a consistent cup of coffee every time?

The universally recognised ‘golden ratio’ for coffee to water is 1:18 – this means 1-gram of coffee to every 18-grams (mL) of water. For a standard cup of coffee (150mL) this means applying a formula of 150/18 to give you a coffee ground amount of 8.3g or 1.6 tablespoons of coffee.

Cups Brewed Coffee Grounds (g) Tablespoons
1 8.3 1.6
2 16.6 3.2
3 24.9 4.8
4 33.2 6.4
5 41.5 8
6 49.8 9.6
7 58.1 11.2
8 66.4 12.8
9 74.7 14.4
10 83 16


150mL is the universally accepted size for a ‘standard’ cup of coffee, but for most of us home brewers, we know that 150mL may be the smaller size – so adjust accordingly. If you’re brewing coffee in a commercial environment such as a café or restaurant, make sure that your hardware (cups, mugs, glasses) is measured and accounted for in your water-to-coffee ratio calculation – consistency is key in your hardware to avoid inconsistencies for your patrons.

Can Coffee to Water Ratio Change?

 Yes, of course!

The water ratio can change based on how you’re brewing coffee, the types of beans that you’re using, and a whole host of other factors that are subject to change based on your environment and desired brewing outcome.

Remember, these ratios are completely subjective. The ‘golden ratio’ of coffee to water isn’t a guiding universal principle, it’s just something that we, as a coffee community, have clung to over the years. The amount of coffee grounds that you use to water is completely up to you and will come down to how you like to drink your coffee, your beans, and your equipment.

Other Factors that Impact Coffee Strength

 Coffee to water ratio isn’t the only variable that affects the ‘strength’ of coffee. Other factors that influence strength include:

  • Types of beans
  • Brewing method
  • Extraction time
  • Grind size
  • Water temperature

Recommended Coffee to Water Ratio by Brew Method

One of, if not the biggest factors to consider when it comes to nailing the right coffee to water ratio is how you brew. Everyone is different and ultimately, the way that you choose to brew your coffee will come down to personal taste, but here’s a simple coffee to water ratio guide for popular brewing methods.


In brewing terms, a 1:1 coffee to water ratio is considered a ristretto. For espresso, this ideal brewing ratio is approximately 2:1 – but this will depend on a myriad of other variables, including hardware, to determine the right setup.

French Press

The most common coffee to water ratio for French press is between 1:15 and 1:17 – depending on preferred taste. A lower ratio (higher amount of coffee to water) is recommended for those looking for a ‘stronger’ cup of coffee.

Pour Over

Like the French press, pour over brewing ratios typically range between 1:15 and 1:17 and can be adjusted according to beans and desired taste. 


The recommended golden brewing ratio for AeroPress is 1:16. This means 16mL for each gram of coffee that is used. Your AeroPress can hold a maximum of 240mL of water which means that you’ll want to use 15-16g of coffee grounds in your brew.

Cold Brew

For a full-bodied cold brew, a brewing ratio of 1:5 – 1:6 is the sweet spot. For a lighter brew, this can be extended all the way out to 1:8. Of course, the higher ratio of coffee to water means that you’ll need to adjust your normal pour over/drip coffee consumption accordingly in the warmer months so that you don’t overdo it.

Drip Coffee

For drip coffee, a brewing ratio of 1:17 is recommended for a ‘normal’ strength. Drip coffee is an extremely efficient brewing method which, depending on your hardware, will require less coffee than other brewing methods. Depending on your hardware, there is a good chance that you’ll find a loyal online following that discuss the perfect brewing ratio for your chosen drip coffee model – so start with an online search.

Brewing Method Recommended Ratio
Espresso 2:1
French Press 1:15 to 1:17
Pour Over 1:15 to 1:17
AeroPress 1:16
Cold Brew 1:5 to 1:8
Drip Coffee 1:17