Bitter Moka Pot Coffee: Causes And Solutions


Moka pots can produce a wonderfully strong and thick coffee that’s almost like espresso. But sometimes it can also produce a super bitter, burnt tasting cup that’s undrinkable. What’s going on and how can you prevent this? Here’s what you want to know. 

If the coffee from a moka pot is too bitter, there are a few things that can cause this: Type of coffee used, ratio, grind size and excessive heat. Moka pots will always produce more bitterness than some other brewing methods like pour over or French press. 

Let’s dive into what excessive bitterness actually is, what went wrong and how to improve in detail. 

Is Your Moka Pot Coffee Too Bitter? 

If your coffee is too bitter is completely up to your personal taste. Many people like a bit of bitterness in their coffee and others don’t like anything at all. I personally like my bitterness to be quite mild and while it doesn’t have to be completely absent, I don’t like the harsh bitter, burnt notes though. 


If you think the coffee is too bitter, then it is too bitter. It’s completely up to you and your taste. Moka pot coffee is always going to be more bitter than a pour over or French press. There are things you can do to reduce bitterness however. 

There are things you can do to make your moka pot coffee less bitter but there will always be some in this brewing method. There is only so much you can do to reduce it. If you like the level of bitterness of pour over coffee but not more than that, you’re going to have a hard time making moka pot coffee tasting good for you. 

A moka pot makes coffee that’s close to espresso (but not completely). You use a lot of coffee grounds for the amount of water and extract it with very hot water under pressure which means it’s very strong. Coffee always has some bitter notes in it. If you make coffee very strong, you get more of the bitter notes as well.

The type of coffee, roast level and some specific actions during the brew process can strongly impact the level of bitterness though. Some thing you can impact before and during the brewing process can really crank up the bitterness to unpleasant levels. 

So knowing that a moka pot is always going to be a little bit more bitter than brewing methods like a pour over or French press, what are the things that make moka pot coffee excessively bitter? And what can you do about it? 

What Makes Moka Pot Coffee Bitter?

So let’s take a look at the factors that can actually cause this excessive bitterness. These are the things outside of the moka pot so these are factors you can control.

Coffee Choice

The biggest thing that causes a moka pot to brew excessively bitter coffee is the type of coffee beans and how they’re roasted. The bean that brews good coffee with one brew method doesn’t necessarily produce good results with another. So even if you’re using the same coffee you like to drink with another brew method, it’s possible that it just doesn’t taste good with a moka pot. 

The choice of coffee is where everything starts. If you use bad coffee, you’re going to get bad results. The specifics of brewing only have a relatively small impact on the taste compared to the beans used. 

There are a few different things that you should know about coffee to get the best results;

Roast level

The most important to understand is the roast level. There is a lot that goes on during the roasting process and it’s quite complicated. Roast level has a large impact on taste and how a coffee brews. One dark roast is not the other dark roast but we can find some generalities in taste with the different roast levels. 

The lighter a coffee bean is roasted, the more of the origin characteristics you can taste. Light roasts have quite a bit of acidity and very little bitterness. The body and mouthfeel are also a bit thinner. 

Darker roasted beans lose more of the origin characteristics, and gain more dark, bitter tastes. There is very little acidity in dark roasted beans. The liquid it produces is also darker and feels a bit thicker in your mouth. It’s almost like caramel. The darker, the more bitterness. Most people are used to drinking dark roasted coffee and that’s what they expect from their cup. However, if you feel you have too much bitterness, going one roast level lighter is a good idea. 

Besides the beans developing more bitterness with darker roasts, the darker beans are more porous and therefore easier to extract. The bitter tastes are usually the last to be extracted out of the coffee so more extraction equals more bitterness. So using a lighter roast has the double effect of having less bitterness to begin with but also extracting slower and therefore giving off less of those bitter notes. 

Type of beans

There are two main types of coffee beans; Arabica and Robusta. Arabica is more fruity and less bitter while Robusta is much darker and bitter tasting. However, that is a gross generalization. I’ve had Robusta coffees that are more fruity and have less bitterness than some Arabicas. However, in those cases, we’re talking about specialty coffee. There are so many types of Arabica and Robusta that’s it’s impossible to cover them all. 

Most coffee you buy in the supermarket is not the highest quality and there will be quite a bit of bitterness in both Arabica and Robusta beans there. However, Arabica will on average be significantly less bitter than Robusta. Look for coffee that mentions “100% Arabica”. If the bag doesn’t mention this, you can assume there is at least some Robusta mixed in. 

Fresh beans

If coffee is very old, the taste can go off. Coffee is well past it’s peak after the bag has been open for 6 weeks or more. Pre-ground coffee goes stale even faster. Old coffee can taste flat but some other unpleasant tastes can become stronger. So buying a fresh bag could improve your coffee quite a bit. 

Of course grinding your own coffee is going to be best. Because whole beans have less surface area exposed to the air which is what ages coffee. Ground coffee has much more surface area which is why you can brew coffee with it but that also means it goes stale quickly. 

Quality

Higher quality coffee tends to have a little less of the really harsh bitterness than lower quality coffee. Higher quality coffee is usually more expensive but that’s not a guarantee of course. A good way to get higher quality coffee is to go to a local coffee shop that sells coffee they roast themselves. They’ll be able to provide you with something that’s right for you and the quality of the beans will likely be higher than what you get in the supermarket. 

Heat

Heat is a part of the brewing process you have some influence over and does impact the taste of the final brew. 

If there is too much heat or it takes too long for the water to boil, it gives more time for the grounds to get hot and burn. They basically get roasted again which means more bitterness. 

On high heat, you build pressure faster. But higher pressure means a higher boiling point and so the water that hits the coffee is even hotter. Higher pressure and higher water temperature means the grounds are extracted more. Too much extraction creates excessive bitterness.  So too much heat is a double whammy of bitterness. 

A moka pot brews coffee by creating steam and therefore pressure that pushes the water through the bed of coffee. To create pressure, the water has to boil and steam. That means you need a significant amount of heat. That’s unavoidable but the heat should be managed.

It’s best to start with hot water in the moka pot. Boil it in a kettle and pour it in the boiler of the moka pot. That way, you dramatically reduce the time it takes to boil the water and this limits heat exposure. 

It’s also a good idea to use a medium-high heat setting. Avoid the highest setting to limit pressure build up. This does mean it takes a little longer but starting with hot water more than offsets this. 

Grind Size

If the coffee is ground too fine, there are a few things that can happen and make your coffee really bitter. 

The finer coffee is ground, the more surface area there is. More surface area means that the water touches more at the same time and more is extracted at the same time. The last compounds you extract from the beans is very harshly bitter. Extraction is a balance, too fine and your coffee will be too bitter, too coarse and it’ll be weak and sour. 

Also, very fine coffee can clog up the holes in the filter. This could lead to more pressure being built. More pressure means higher temperatures. More pressure and higher temperatures lead to excessive extraction. 

In extreme cases, the filter can get completely clogged and no coffee is coming out at all. 

The best grind size for a moka pot is medium-fine, slightly coarser than espresso grounds. Comparable to table salt is a good starting point. If you don’t grind your own coffee, you sadly don’t have a lot of control over this. Different brands can have slightly different grind sizes so experiment with different bags of coffee. 

To be able to set the grind size, you have to grind your own coffee of course. Getting a hand grinder allows you to use fresh beans which is a massive improvement in itself but also allows you to change the grind size. The TimeMore C2 (Amazon) is a good hand grinder that works fast, gives good grind quality and has plenty of adjustability for a moka pot and many other brew methods.

Suggested: What’s the best grind size for a moka pot?

Ratio

The ratio of grounds to water does have an impact on bitterness and taste overall. You might think that reducing the amount of grounds will result in less bitter coffee. It might seem counterintuitive but less grounds will actually increase the bitterness. 

In general, filling a moka pot boiler to the safety valve and the filter basket to the rim is going to give you decent results. Weighing both the amount of water and grounds is going to be much more accurate and consistent. Especially if you have issues with your coffee being good one day and bad another day, weighing will get you better consistency. 

Aim for a 1:8 ratio of grounds to water. That’s a starting point, feel free to adjust from there. Make small changes in the amount of grounds you use and see if you’re going in the right direction taste-wise.

The way to know exactly how much coffee and water you put in your moka pot is by using a scale. A coffee scale can really bring your coffee to the next level. You can get a simple one for not much money on Amazon.

Suggested: How much coffee grounds goes in a moka pot?

How To Make Moka Pot Coffee Less Bitter

Above you can read the most common causes for excessively bitter coffee from a moka pot. There are some solutions in there as well. But here is a quick summary of the things you can try to make your moka pot produce less bitter coffee. 

  • Use Arabica coffee of good quality
  • Try a lighter roast level
  • Fresh coffee produces better balanced coffee
  • Use more grounds if there’s space left in the filter basket
  • Start with hot water in the boiler
  • Use a medium-high heat setting
  • Use a slightly coarser grind size

Recent Posts