Why Does My Coffee Taste Watery/Weak?

January 11, 2023

Watery coffee is the worst. When it tastes thin. Lifeless. Lacking in body and fullness… And the tricky part is there’s not any one fix that works.

So what I’m gonna do here is break down exactly why your coffee might taste watery. There’s 3 things you could be doing wrong. And I’ll give you a solution for each one. Read on, follow the advice, and your coffee will taste delicious and full-bodied again.

Why does my coffee taste watery/weak?

Reason #1: Your coffee water ratio is off

If you use too little coffee for the amount of water you’re using, your coffee will taste watery. Sounds obvious, right? But how do you know what is the right amount of coffee? Let’s get specific.

Let me introduce you to the “coffee to water” ratio. This is what all the pros do to make sure their coffee is perfect. Among other things, you can use it to make sure your coffee isn’t too watery. Here are the numbers:

Coffee is first and water is second, so it’s like coffee:water. Another thing is that you can’t just eyeball it. If you want to figure out the strength — and solve your watery coffee problem — you need to measure the amounts.

(By the way, we like to use grams and milliliters in the coffee world. You can use ounces, but they’re kinda big and cumbersome)

Fix: Use more coffee grounds (or less water)

Ok so you’ve got your scale out now. You’ve put your coffee grounds in a little cup and the display says 15g. Next, you weigh your water and it’s 250g. That means your coffee to water ratio is about 1:17. Let’s look at the table again.

A 1:17 ratio is “Quite weak”. So that might be the reason your coffee is coming out watery. How do we fix it?

Well, you can either up the amount of coffee grounds you’re using. So in this case 17g (with 250g water) of coffee would give us a “Medium” strength coffee.

The other thing you can do is reduce the amount of water you use. So 225g (with 15g coffee) of water would give a “Medium” strength coffee.

Want to try it strong? Both 1:13 and 1:11 are acceptable ratios in the coffee world. Fair warning, though. Any higher and it’s going to be a bit unusual.

Either way, at this point you should have an idea whether this is solving your watery coffee issue. If it isn’t, then you need to look at reasons #2 and #3 to fix your weak coffee.

Reason #2: You are underextracting the brew

An underextraction in the brewing process is a classic problem, and one that will lead to watery and weak coffee. Before I tell you what the fix is, let me explain what is meant by an underextraction.

When you brew coffee, you are letting the coffee grounds interact with hot water. This causes the coffee solids to dissolve into the water and make coffee. If the brewing process is bad, then not enough solids will dissolve and the coffee will taste weak.

For example, if you brew a French Press for only 30 seconds then that’s not enough time for a proper extraction (probably). The thing is… it’s not just brew time. There’s lots of variables that can cause an underextraction.

A sign that you’re underextracting your coffee is sour or acidic flavors in your drink. This is because the more acidic compounds in coffee extract first.

Sound complicated? This is a reality of brewing coffee. It’s not like tea, where you can let it sit for a while and know that a minute or two either way is gonna make any difference. Coffee is a finicky little substance. If it wasn’t, you probably wouldn’t be on this website looking for advice!

Fix #1: Brew for longer

If you’re using an immersion brewer like a French Press or an Aeropress, you can simply brew for more time. The more exposure the ground coffee has with the water, the more solids will dissolve into your coffee and therefore make your coffee taste less weak.

Fix #2: Use a finer grind

A finer grind size for your coffee grounds — basically smaller coffee grounds — can speed up the extraction. Larger coffee grounds take longer to extract. It’s a surface area thing. This is particularly an issue with percolation brews like Pour Over or anything where you don’t control the brew time. The fix is quite simply, and that’s to go a couple of notches down on your grinder. The finer coffee grounds should lead to less watery coffee.

Fix #3: Use hotter water

The speed of your extraction is also dictated by the termperature of the water you are using. Cool water will take longer to extract, and give you weak coffee. So try using hotter water. Water that is straight off the boil is fine and is usually about the recommended temperature. Try it for hotter water which may solve your weak coffee problem.

Fix #4: Expose the coffee grounds to the water

The last problem with the brewing process might be that you have some coffee grounds that aren’t being exposed to water and so can’t extract. The solution to this is different for every method. For French Press, trying mixing the grounds into the water with a spoon. For Pour Over, you need to use a clean grind and spread the water out (with a spiral pour?) to prevent channeling. However you do it, make sure all the coffee grounds get a chance to extract into the water may lead to stronger, less watery coffee,

Reason #3: There’s not enough caffeine

This last problem is when the taste of your coffee is ok, but it’s lacking a bit of a “buzz”.

If your coffee doesn’t taste watery or weak, that means you’re brewing it fine. So you can ignore reasons 1 and 2. But to get more of a buzz you simply need to use more coffee.

Fix: Make more coffee

A normal amount of ground coffee is between 12 and 30g for a single drink. The average caffeine content for a gram of coffee is 13.5mg, so take a look at this table to see how much caffeine you get in a drink.

To put this into context, a decent sized coffee is considered to be about 150-200mg. The largest size (grande) at Starbucks has 310mg of caffeine. And the RDA states here that up to 400mg per day seems to be healthy in adults.

So choose your poison, basically. If you use 30g of ground coffee, that’s a high amount of caffeine but might be what you need personally for your coffee to taste stronger.

Do bear in mind you build up a tolerance to caffeine. Over time, you’ll find you need more and more to still keep the same “rush”.

P.S. Espresso works a little differently, but you can find out the caffeine per espresso shot in my article here.


One last thing. Your choice of brew method does make a difference when it comes to how full bodied your coffee is.

Before I say how, I should point out that watery coffee is a problem. And one of the above three reasons should fix it, however you brew your coffee.

But if you want the strongest, most full bodied coffee possible… your best bet is an immersion brew that doesn’t use a filter. A French Press, basically. If you don’t have one, check out my review article here.

Long story short. The French Press is known for its full bodied brews (just watch out for the sediment!)

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