Coffee Brewing Ratio: The Perfect Cup Guide

Ever made a coffee that tastes incredible one morning and completely different the next? Your coffee brewing ratio might be the culprit.

Getting the right balance of coffee and water is one of the easiest ways to improve your brew. And no, you don't need to be a professional barista or have a kitchen full of fancy equipment.

Here's how to get it right, every time.

What is a coffee brewing ratio?

A coffee brewing ratio is simply the amount of ground coffee you use compared to the amount of water. Nothing too complicated. You'll usually see it written as 1:15, 1:16 or 1:18. The first number is your coffee, the second is your water. So, a 1:15 ratio means 1g of coffee for every 15g of water. Brewing with 20g of coffee? You'll need 300g of water.

And here's a handy little shortcut: 1ml of water weighs approximately 1g. So, 300ml of water is roughly 300g.

That's the maths sorted. Now for the good stuff…

The Golden Ratio: A reliable starting point

So, is there a magic number for making the perfect cup of coffee? Well, sort of.

The Specialty Coffee Association (SCA) recommends around 55g of coffee per litre of water (roughly 1:18). But for most filter brewing methods, anywhere between 1:15 and 1:18 is a great range to experiment with.

The difference? It's all about how you like your coffee.

• - 1:15: A stronger, fuller-bodied brew with more punch.
• - 1:16: A good middle ground, balancing strength and flavour.
• - 1:18: A lighter, more delicate cup that lets subtle flavours shine.

At Rave, we often recommend starting around 1:18 and adjusting from there. Different brewing methods call for different approaches, though, so it's worth checking the recommended ratio for your favourite bit of kit.

Think of the golden ratio as a starting point, not a rulebook. Your taste buds get the final say.

Why the ratio matters: strength & extraction 

Too much coffee, too little water (or vice versa), and your brew might not taste quite how you'd hoped.

There are two things at play here: strength and extraction.

Strength is how concentrated your finished coffee is, while extraction is how much flavour you've managed to draw out of the grounds. Get the extraction wrong and your coffee might taste:

• - Under-extracted: Sour, sharp or lacking sweetness. Not enough flavour has been extracted from the coffee.

• - Over-extracted: Bitter, dry or unpleasantly astringent. Too much has been extracted from the grounds.

Your coffee-to-water ratio influences both, but it's not the whole story. Grind size, water temperature and brewing time all have a part to play.

So, before throwing more coffee at a disappointing brew, it might be worth checking your brewing method too.

Recommended Brewing Ratios By Method

Not all brewing methods are created equal. What works for an espresso won't necessarily work for a cafetière, and cold brew is a whole different ball game.

So, how much coffee should you actually be using? Here's a handy cheat sheet.

A couple of things worth keeping in mind:

• - Espresso works a little differently. The 1:2 ratio refers to the weight of your finished shot, rather than the water going into the machine.

• - Cold brew can be made as a concentrate. Our 1:5 recipe makes a stronger brew that's designed to be diluted with an equal amount of cold water before drinking.

Fancy getting a little more technical? We've got step-by-step guides for filter coffee, pour-over, AeroPress, espresso and cold brew.

How to measure: scales vs spoons

We're all for keeping coffee simple, but if there's one bit of kit worth investing in, it's a decent set of scales.

Why? Because tablespoons aren't particularly precise. The amount of coffee in a scoop can vary depending on the grind size, roast and how generously you've filled it. Not ideal when you're trying to recreate that perfect cup.

A tablespoon of ground coffee typically weighs around 5–7g. So, if you're brewing a 300ml cup at a 1:18 ratio, you'll need roughly 17g of coffee, or around three level tablespoons.

It's not an exact science, but it'll get you started.

For a little more consistency, we'd recommend digital coffee scales. They'll help you measure both your coffee and water accurately, making it much easier to repeat a great brew.

How to adjust the ratio to your taste

Here's where things get interesting. Once you've nailed your starting ratio, it's time to experiment a little.

• - Fancy a stronger coffee? Try using slightly more coffee for the same amount of water. For example, move from 1:18 to 1:16.

• - Prefer something lighter? Use a little less coffee, moving towards 1:18 or even 1:20.

But don't forget, your coffee-to-water ratio is only part of the equation. Grind size makes a big difference too. If your coffee tastes sour or sharp, try grinding a little finer. Too bitter? A coarser grind might help.

The coffee itself matters as well. Lighter roasts can benefit from a finer grind or longer extraction, while darker roasts often need a gentler approach to avoid unwanted bitterness.

And if you're chasing a serious caffeine kick, it's worth remembering that strong coffee and highly caffeinated coffee aren't necessarily the same thing.

Our advice? Change one thing at a time. That way, you'll know exactly what's making your coffee taste better (or worse).

Common brewing ratio mistakes to avoid

Even with the best coffee beans, a few little mistakes can throw your brew off balance. Here are some common culprits to watch out for:

•  - Eyeballing your measurements: A little guesswork is fine, but consistency makes a good brew easier to repeat.

• - Assuming stronger means better: More coffee doesn't automatically mean more flavour.

• - One ratio fits all: Different brewing methods need different approaches. Espresso and cafetière are hardly interchangeable.

• - Changing everything at once: Adjust one variable at a time, or you'll never know what made the difference.

Recommended beans & kit to nail your ratio

Got your ratios sorted? Now for the fun part.

Start with some freshly roasted Rave coffee beans. Whether you're into bold, chocolatey blends or bright, fruity single origins, there's plenty to experiment with. Can't decide? Our coffee taster packs are a great way to try a few different coffees and find your favourites.

And if you're looking to take things up a notch, a good coffee grinder lets you fine-tune your grind for different brewing methods. Freshly ground beans? Even better.

Good beans, a little precision and a willingness to experiment. That's a pretty solid recipe for a great cup of coffee.

Frequently Asked Questions

What is the best coffee-to-water ratio?

There's no one-size-fits-all answer, but for most filter brewing methods, 1:15 to 1:18 is a great starting point. Other methods, like espresso and cold brew, use very different ratios, so it's worth checking the recommendations for your chosen brewing method. From there, it's all about finding what tastes best to you.

What does a 1:15 coffee ratio mean?

It means using 1g of ground coffee for every 15g of water. So, if you're brewing with 20g of coffee, you'll need 300g of water. Simple as that.

How much coffee do I use per cup of water?

That depends on your brewing method and cup size. For a standard 250ml filter coffee, around 14–17g is a good starting point. Espresso uses much less water, while a cafetière or cold brew calls for different proportions. Check our brewing ratio table above for the full breakdown.

Is the brewing ratio different for French press and espresso?

Absolutely. A cafetière typically uses around 1:13 to 1:17, while espresso usually starts at 1:2. The important difference? Espresso ratios measure ground coffee against the weight of the finished shot, rather than the water added.

Can I measure my coffee ratio without scales?

Yes, sort of. A tablespoon of ground coffee typically weighs around 5–7g, so you can use spoons as a rough guide. Just bear in mind that grind and roast can affect how much fits on a spoon. For more consistent results, we'd always recommend scales.