Why is my coffee bitter, sour or burnt?

Why is my coffee bitter, sour or burnt?

Sometimes in the morning it’s hard enough to find your wallet, keys and phone, let alone try to troubleshoot a coffee that just tastes off. We’ve all experienced a brew tasting bitter, sour or burnt, but it doesn’t have to ruin your day. These problems can often be fixed with a quick adjustment and re-brew, provided that the problem is not the coffee beans themselves.

Espresso coffee tastes best when made with medium-roast beans. Beans that are too fresh can taste sour, as they haven’t had time to degas. From about a week after roasting your coffee will have settled in and will be beautiful for espresso based coffees.

Coffee roasting green to light to dark.

Assuming you have great quality coffee beans and they aren’t too fresh, this guide will help you solve some issues with the coffee extraction.




Words to understand

Extraction = This refers to the pour of the coffee from your espresso machine. It’s extracting the coffee oils from the beans.

Blonding = When the coffee pour is a pale yellow colour

Basket = The basket holds the coffee grinds which the water flows through

Crema = The light brown oils that sit atop the coffee shot.

Puck = The coffee grinds that remain in your basket after you have run a shot. The make a shape like a hockey puck when you empty the basket out.



Why does my coffee taste bitter?

What to look for:  Your puck will be super soggy and sloppy. A thin white/pale yellow watery pour and spirals at the end. Big patches of white on your crema


Coffee Blonding


Diagnosis: When your espresso comes out tasting bitter, it usually means that the extraction or pour time is too long. Commonly, you’ll see a pale yellow/white stream of coffee that wobbles and spirals towards the end of the shot.

Remedy: Adjust your brew time. A good pour will be somewhere between 25 – 35 secs. Keep watch on the shot as it comes through and as soon as you see the coffee coming out in a light “blonde” colour, stop the shot immediately. This is almost pure caffeine and caffeine tastes very bitter so you want to avoid this and stop the shot as soon as you see it start blonding. Most people make the mistake of trying to extract too much coffee out of a single coffee dose. If you want a strong coffee, get a bigger basket (22g – 28g) and keep the shot time within the ideal range. Don’t worry, you’ll still get your caffeine fix, it just won’t be as bitter.


Why does my coffee taste sour?

What to look for:  The coffee GUSHES out under 15 seconds and is wide, pale yellow and bubbly. Your puck will be really dry and powdery.


Coffee Under-extraction


Diagnosis: A sour espresso shot is one that is under-extracted; meaning the water has run through the coffee too quickly and hasn’t extracted the delicious tasting oils. You are either not putting enough coffee in your basket or you are tamping too lightly and your coffee is too coarse. If your shot pours in under 15 seconds, you are getting under-extracted coffee. The coffee will appear blonde and pale and bubbly. The coffee crema will also dissipate rapidly and the taste will appear thin and sour.

Remedy: To fix a sour espresso shot,  adjust your grind to be finer. This will mean that when you tamp the grinds you’ll create more resistance for the water to pass through allowing it to pick up more oils along the way.


Why does my coffee taste burnt?

What to look for: Slow dripping for almost the entirety of the shot. Dark/black pours. You only get a small volume of coffee liquid even after a 45 second extraction. Your puck will look soggy and sloppy again.

Coffee Over-Extraction


Diagnosis: Burnt tasting espresso has been over extracted, meaning the hot water is flowing through the grinds too slowly creating harsh and burnt tasting espresso. You coffee grind is too fine or you are over filling the basket and tamping the coffee too much.

Remedy: To remedy a burnt tasting espresso shot, adjust your grinder to a slightly coarser grind. This will help the water to seep through the grind more evenly without too much resistance, and it won’t overcook the coffee.


If you try out any of these fixes and they don’t work, leave us a reply and we’ll try and give you specific and detailed help! No one has time for dodgy tasting coffee.

22 comments on "Why is my coffee bitter, sour or burnt?"

  1. Lidia says:

    Fantastic post, very useful, thank you!

  2. Alice says:

    Very helpful, thank you! A coarser grind did fix the burnt flavour.

  3. Jessica Simmons says:

    Can the bitter taste come from the origin of beans you are using?

    1. Ryadan Jeavons says:

      It generally isn’t the origin of the bean but can come from the species of coffee as there are some bitter tasting varietals. It can also be how it is roasted, if it’s a darker roast then it can often be quite bitter too.

  4. Alexis says:

    Over the last two days at work, the coffee has been extremely bitter, almost undrinkable.
    I’ve tested it by adjusting the grind both course & fine, no noticeable difference.
    Is there a chance that it’s the coffee machine itself? The water temperature is at 95°C from last check.
    Even the grinder has an extremely bitter smell to it now though.
    I’m coming in after the previous barrister left, so I’m unsure when they last cleaned the grinder itself… However the coffee was fine last Friday and Sunday.

    The beans themselves are currently being tested by the roaster.

    I’m at a loss here.

    1. Ryadan Jeavons says:

      Hi Alexis,
      Best approach is to do a process of elimination. Grab some good quality beans from somewhere else and try them through the machine. If they are bitter as well then you know it’s something to do with the machine or the way they are pouring.
      Most likely case is that the beans are the cause of the bitterness. What does the coffee look like? Is it dark roasted?
      If you think it’s not the beans there is a chance that the machine is very dirty and probably hasn’t been cleaned with chemical to remove the old oil and grinds that build up in the machine. This can cause a dirty bitter flavour. Remove the screens from the group head (you’ll need a screwdriver or Allen key) and see if they are caked in old coffee. If so, soak them overnight in chemical. Probably also need to soak the portafilters too as this could also be affecting it.
      Good luck!
      Let us know how you go!

  5. Natalia says:

    I have had the issue of fast extraction (~20sec) but the pour comes out quite thin, long and dark. Have been tried adusting the grind to be coarser and having more in the basket, but this doesn’t seem to have much of an effect. What do you suggest is the problem? (I am told the beans we are using like a fast, bubbly pour over 27-30sec).
    Please help!

    1. Ryadan Jeavons says:

      Hi Natalia!

      Most likely, when the coffee is thin and dark and is coming out quickly, that is a sign of old coffee. They have completely degassed and so there is no oils left in there to create resistance so the water rushes through and only causes a thin extraction.

      Even if they are not old but have been left open and exposed to the elements they will still cause a thin and dark coffee extraction.

      Hope this helps!

  6. Jean Luc Tin Sive says:

    Hi I’m pulling shots of 1:2 brew ratio in 25-30sec. Everything looks good but the shot tastes sour. Coffee roast date for about a week. What could be wrong?

    1. Ryadan Jeavons says:

      In this case, I actually think your coffee is TOO fresh. 😄
      There is a common misconception that espresso coffee needs to be freshly roasted. It has so many gasses after roasting that these give off a sour flavour and so you’ll need to give your beans time to degass.
      When you’re in winter months you’ll need a lot more time to degass (about 2-3 weeks is when it settles in). In summertime it will be quicker so you can almost start using it after one week.
      If you can’t wait that long, you can kinda cheat it by grinding your coffee dose a few minutes ahead of putting it in the group basket.

  7. Jean Luc Tin Sive says:

    Thanks for the quick reply! I was using the bag of beans for about 2 weeks after and it was still sour about 3 weeks past the roast date. Maybe I’m confusing the sour and bitter? It kind of feels “salty” which is closer to sour to me.

  8. Ryadan Jeavons says:

    And you’ve had this coffee before and it hasn’t been salty/sour?

    The other possibility is that the machine needs cleaning and that taste is coming from left over grinds and oils that have built up over time. When was the last time you cleaned the machine with chemical? Is it a new machine or old?

    Also, have you tried other coffees to compare.

    If you’re getting a nice slow thick pour in about 25-30secs and getting a 2:1 in/out ratio and it’s degassed, then I’m left to believe it has to be the roast or varietal characteristics.

  9. Jean Luc Tin Sive says:

    I’ve never had a perfect non salty shot 🙁

    The machine is 2 months old and I backflush every month.

    Single origin/light roast coffees seem to less salty than blends.

  10. Sam says:

    Hi, my coffee comes out sour and quite cold even though the extraction is near perfection. I can not seem to fix this with any meathods that are online.(I have the rancilio silvila M) What am I doing wrong.

    1. Ryadan Jeavons says:

      Hi Sam,

      When you say it comes out cold is it because the water is cold? Run the water from the machine and feel how hot the temperature is. If the water is only lukewarm, you may have an element issue. The water should be almost boiling (approx 93C or 199F) so make sure you test that first.

      If the water is hot but the shots are coming through cool still, check that the portafilter (group handle) is definitely hot on the metal part. If this is cold, it’s going to dramatically absorb all the heat from the water passing through the coffee grinds and won’t extract the coffee oils properly.

      If your coffee is still sour tasting and the coffee isn’t too fresh (eg: 2-3 weeks after roasting) you may need to post a link to a video of you pulling a shot (film it up close) and we can assess it.

      Good luck!

  11. Thomas says:

    Hi, I’m a little lost and hope you can help me. Most of my shots are in the range of sour to undrinkable sour.
    I’m using a Profitec T64 grinder and a Profitec Pro 600. In a first step, I’ve tried all possible grind sizes leading to extraction in 15s up to +1min with pretty much the same result. Even when over extracted it seems sour.

    Temp. is set to 92C and pressure is ~10bar. With a in/out of ~1:2 (18g in / 40g out) it’s sour. Tamping is consistent with a pressure-regulating tramper.

    I’ve tried 3 different beans:
    First one is my favorite. I’ve previously used them with a Pavoni Professional for ~4 years and never had shots this sour even when over/under extracted. I was unable to get a drinkable shot with them.
    The second one was sour no matter what I’ve tried.
    The third one did have an exception. When i got them and used them the same day, I’ve got drinkable shots without much experimenting (~1:2). I’ve used them every day now and they degraded from drinkable to undrinkable sour in just one week. I’ve only adjusted the grind size finer since the shots under extracted more each day. I’m now back to where i was before.

    Beans 1 and 3 were fresh ~2-4 weeks old. Not sure with no.2.
    Is it possible that the beans got sour that much in just one week?? I’ve never had that when i was using the the La Pavoni and a hand grinder, I’ve sometimes used beans (no1) for over one month. What can i try to do?

    Other things I’ve tried was increasing/decreasing temp and pump pressure (with same grind size) both leading to even worse shots. Last thing I’ve tried was using bottled water since it’s quite hard here, but i don’t see much difference.

    From my experience with the La Pavoni something seems off here but i have no idea what.. can you help me?

    1. Ryadan Jeavons says:

      Hi Thomas,

      Definitely seems strange that you’re getting sour shots on everything from what you told me.

      Are you in a hot climate right now? I’ve had coffee take up to 4 weeks just to degass before the shots aren’t running about anymore. It could be that they need longer to degass.

      Are the beans light roast or light medium roast? These generally taste sour when running through espresso machines.

      Are the shots bubbling when they drop? This is a sure sign they are still holding a lot of carbon dioxide which will be sour.

      Maybe also put your temp up to 95 degrees and see if that helps at all.

      You can also try doing a shot at 22-24g over 27-30secs and get about 40ml and see if that gives you any better results.

      Good luck!

    2. Ryadan Jeavons says:

      Hey Thomas, I just had a thought which might be nothing but I thought I’d ask what sort of basket you are using? From the precision equipment, you have already described I assume you are using a double shot basket with straight sides and not a single basket with tapered sides?

  12. Ákos says:


    What should I do if my coffee starts blondig at ~17 seconds, but if I keep brewing it and stop the shot at 25 seconds the brew ratio will be good (1:2-1:3)? My main problem is that the coffee tastes burnt, but if I adjust my grinder to a coarser setting, the brew ratio will be bad (>1:3) and the blonding starts sooner.

    This is a freshly roasted coffe from a local certified coffee roastery (Vienna roast, 2.5 weeks old) and it should taste like a chocolate. Instead it tastes burnt or if I keep adjusting my PID temperature, it tastes sour or bitter too, but no signs of chocolate or anything good. I think I should fix my blonding issue to solve this, but I’m not sure how. Or I miss something more important thing?

    What is your suggestion?

    1. Ryadan Jeavons says:

      Hey Akos!

      I think sometimes too much emphasis is placed on the science of coffee and not enough on the art. Whilst it’s good to get the brew ratio to 1:2 I think watching the shot fall and cutting it before it starts blonding is much more important and obviously, the taste is the MOST important part! I’m guessing the beans are a little oily looking and shiny? This is the Vienna roast process which roasts the coffee for a longer period so that the oils which are trapped inside the bean, come to the surface.

      I’m not a fan of Vienna Roast coffees, I know that coffee is very subjective and whilst SOME people still prefer the dark bitter and roasted (essentially burnt) flavors of coffee, the majority of people these days are wanting a smoother, balanced taste. Vienna roasts will never get you the smoother flavors and by the sounds of your description, you don’t like the bitter & burnt flavors either. This Vienna roast coffee will not get you the flavours you are seeking, I don’t think. Dark roasts generally degass a lot more quickly too, so that could explain the early blonding in each extraction.

      I would be looking for a Medium roasted coffee(also sometimes referred to as “American Roast”) where the essential oils are still contained inside the beans and will get picked up when you extract.

      That’s the first thing I would look at. After that, aiming to get a shot that falls perfectly for 25-30 seconds. I wouldn’t be mucking around with the temperature too much, what is your current temp set to? If it’s at 93-95 degrees celsius I’d leave it at that.

      Focus on the consistency or your tamp and how much you put in vs how much comes out.

      Good luck and let me know how you go!

  13. Tomer says:

    I stopped the extraction when it started to blond,
    It took 25 seconds and extracted in a ratio of 1:2, yet the coffee tasted burnt and very strong..
    It was roasted 13 days ago..
    Any suggestions? 😄

    1. Ryadan Jeavons says:

      Hey Tomer!

      That extraction sounds perfect from your timing, to stopping when it blonds, so the only thing that I can think of is that your beans are roasted too dark.

      It has to be the reason.

      I mean, the coffee could be a Robusta bean which isn’t as smooth and sweet as the Arabica family, but it really sounds like the roaster just took the bean too far.

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