Have you ever had a particularly watery, or strong cup that didn’t taste right? It wasn’t the coffee or milk, you just didn’t get your ratios of water to beans right. The perfect ratio of coffee to water is what every coffee addict strives for and if you hit it, in theory you should have the best cup every time.

But does it really matter?

The short answer is yes, it definitely does.

Getting the correct ratios might seem like a basic coffee skill, but there’s minimal room for error and even a little bit over and under could have grim consequences for your brew. It’s not just beginners who get it wrong either, you would be surprised how many long term coffee lovers make a mistake or fall into bad habits.  

WHAT’S INVOLVED IN THE RATIO?

The ratio refers to coffee in its dry, ground form and the boiling hot water we use for it. It doesn’t refer to any creamer you add for flavour, it is just the brew.

As coffee is 99% water, it’s always the larger number in the ratio. Don’t get this the wrong way round or you could have one strange cup of coffee on your hands.

Only when you have the correct ratio of coffee to water do you achieve the optimal extraction of flavour from the bean. This is why most coffee aficionados will use scales when making their brew to avoid any mistakes.

THE 1:18 RATIO

For a standard brew, most coffee experts agree the perfect ratio lies between 1 gram of coffee to somewhere between 15 and 20 grams of water. This is the usual ratio recommended by roasters and used in coffee shops. Some refer to 1:18 as the “golden ratio” but it’s really down to preference, so feel free to play around to match your taste.

If you’re working in spoons rather than grams, the ratio is 1 tablespoon of coffee for every 4 ounces of water. For something stronger, the ratio drops down to around 1:5 so 1 gram of coffee to 5 grams of water. For weaker, you’ve guessed it, try 1:30 ratio.

NUMBERS TO REMEMBER

Water is listed as grams but the metric is actually milliliters. So when a ratio calls for ‘20’, it means 20 milliliters. A standard cup of coffee is usually between 8 – 12oz/ 240-360 ml, so applying the ratio 1:17 you will need:

8oz/240ml cup – 13 grams of coffee to 227ml of water

12oz/360ml cup – 20 grams of coffee to 340ml of water

EXPERIMENT

While 1:17 is recommended as the ideal ratio, everyone’s pallet is different. The strength and taste of your coffee will change depending on what beans you use and the extras you add for flavour. Don’t be scared to experiment with ratios before settling on your favourite one.