Breville Espresso Tastes Sour (How To Fix?)

Maybe you just bought a new Breville Barista Express you’re trying out some espressos and changing the settings a bit every time. But every single one tastes a bit sour.

Luckily I’m here to tell you some simple things you can do to make your espresso taste less sour and sweeter again.

Why Does Breville Espresso Tastes Sour?

The espresso you made with your Breville espresso machine is sour because the water runs through the coffee too quickly. This can happen if you don’t use enough ground coffee, not using the right grind size or you’re not tamping the coffee. The temperature of the water can also have an effect on the taste. You also might be using coffee beans that are overdue by a few weeks.

breville espresso tastes sour

Low Pressure on Breville espresso machine

When your espresso machine is at a low-pressure level when pulling a shot. It basically means that the water is flowing through the coffee too easily, so your Breville doesn’t have to use a lot of pressure to run the water through. Which results in a sour espresso.

These are the most common things that can cause your Breville to have low pressure:

Not Using Enough Ground Coffee

Using too little ground coffee can cause the water to flow through the portafilter too quickly, resulting in a sour espresso. Using too much ground coffee can cause the water to flow through the portafilter too slowly, resulting in an espresso that is too bitter.

Luckily, Breville made a genius invention for this problem.

When you bought your Breville espresso machine it came with the “razor tool”. This tool allows you to measure out the exact amount of ground beans you need in the portafilter, which is about 18 grams.

Simply put ground beans in the portafilter. Then tamp the coffee with a fair amount of pressure and finally use the razor tool to remove the excess ground coffee.

ground coffee beans

Wrong Grind Size On Espresso Machine

The most common reason your machine isn’t reaching normal pressure is the grind size of the coffee.

If the coffee grind size is too coarse the water can run through easily, so your machine doesn’t have to use a lot of pressure and you won’t get a good shot of espresso.

When using ground size to coarse the espresso pours too fast and you get an espresso with a lot of crema on it but it won’t be a strong espresso and it will likely be very sour. 

This is usually the case when you’re using size 10 above. I like to use grind size 9 for espresso, but it could be different for you depending on the beans you use and the taste you like. You have to try out a few different grind sizes to find the one you like.

A good analogy is to think about it like sand and rocks. If you have a bucket of big rocks and you pour water on it, the water will flow right through.

But if you have a bucket of sand and you pour water on it the water will just sit on top of the sand. It would take a lot of pressure to get the water through.

Check out this full guide on what grind size to choose on your Breville Espresso machine.

Not Tamping The Coffee

Tamping your coffee to make the water run through slower, means your coffee machine has to see more pressure to get the water through

On the left side of your Breville Barista Express, there is a tamper that is held with a magnet.

Take the tamper out and press it in the portafilter. You can use quite a bit of pressure, to make sure the coffee gets dense.

I wrote an in-depth article on why your Breville espresso machine has low pressure and how to fix it here.

tamping coffee

The Temperature Is Too Low On The Breville Espresso Machine

A good rule of thumb is, that the higher the temperature of the water the more flavor it will extract from the coffee. This also means that the espresso will taste less sour.

Here is how you change the temperature on your Breville Barista Express step by step:

  1. Turn off your espresso machine
  2. Hold the program button and press the power button once
  3. Press the two-cup button to increase the temp by 4 degrees
  4. Or press the one-cup button to increase the temperature by 2 degrees
  5. Press the program button to reset the temperature to the default setting

What Is The Best Temperature To Use For An Espresso Shot?

A lot comes down to personal preference when deciding what the best temperature is for you.

Although the ratio between the amount of coffee and water used has the most impact on the flavor of espresso. Just like the water pressure in your Barista Express, the temperature in your machine also has some impact on the taste.

A good rule of thumb is, that the higher the temperature of the water the more flavor it will extract from the coffee.

Most people would therefore like an espresso that is a bit hotter, as it will be a bit stronger that way. But it could also be that the espresso will then be a bit too strong and bitter for your liking.

A lot of it also comes down to the kind of coffee bean you use. In general, if you use dark roast coffee beans you want the temperature to be anywhere from 185 to 195 degrees Fahrenheit.

For medium-roast coffee beans, I would go somewhere between 190 to 200 degrees. For lighter espresso roasts I would go up to anywhere from 195 to 205 degrees.

Of course, these are all ballpark numbers. You can only figure this out by trying out some different temperatures on your Breville Barista Express.

I wrote an in-depth article on how to get your Breville espresso machine to the right temperature here.

Your Coffee Beans Are Old

Although coffee can’t really go bad (as long as you keep it dry) like the way bread can go bad and get fungi all over it. If you use coffee beans that are older than a month, you will really notice it in the taste of your espresso, it will taste a bit flat and sour after a while. There are some differences depending on the roast you use though.

Light and medium roast coffee beans have a lot less co2 in them than darker roast coffee beans. But light and medium roast beans can also hold co2 a lot better than darker roast beans resulting in them staying fresh longer.

It’s advised you consume dark roast coffee beans within a month. Light and medium roast coffee beans can stay good for a bit longer.

If you’re buying ground coffee, it’s best to consume it within at least 2 weeks no matter what the roast is. Any longer than that and the coffee will start tasting flat and sour.

Make sure to store your coffee in a cool and dark place, It’s best to keep the temperature at or below 70 degrees.

cup of Breville espresso


There are many different aspects that can have an effect on the taste of your espresso and cause it to taste sour. To summarize, here are a few things that can cause your espresso to taste sour:

  1. Not using enough ground coffee
  2. Not using the right grind size
  3. Not tamping the coffee in the portafilter
  4. Not using the correct temperature on your machine
  5. The coffee beans are too old

I hope this article helped you with making your espresso less sour and that you can enjoy a nice sweet-bitter espresso now! If your espresso still tastes sour, there could be a technical problem. Check out this Breville troubleshooting article to find a possible solution.

Thanks for reading!