Guide · Espresso machines
Why is my espresso bitter? Over-extraction, dirty kit and dark roasts
Bitter espresso usually means over-extraction, a dirty machine or a very dark roast. Here's how to tell which, and the fixes Sage and De'Longhi give.
If you’re wondering why is my espresso bitter, there are three usual suspects: over-extraction (the shot ran too slowly and pulled out too much), a machine that needs cleaning, or beans roasted very dark. Over-extraction is the most common, and it’s usually a grind that’s too fine. We haven’t tested this in person. This guide is based on the extraction guides and troubleshooting tables in Sage’s Barista Express and Bambino manuals and De’Longhi’s Dedica manual. Read how we compare.
Why is my espresso bitter? Spotting over-extraction
Sage’s Barista Express manual describes an over-extracted shot like this:
- Flow doesn’t start until after 8 seconds, then drips or barely comes at all.
- The crema is dark and spotty.
- The espresso is very dark brown.
- It tastes bitter and burnt. Sage’s chart labels this end “bitter, astringent”.
Sage’s chart puts the bitter zone at shots running over 40 seconds, against a target of 25 to 35 seconds. Its Bambino manual gives a simpler test: if the shot starts to drip but doesn’t flow after 12 seconds, the grind is too fine.
The fix, in order
Change one thing at a time, then pull another shot.
- Grind coarser. Sage’s first fix for a slow, bitter shot is to turn the grind size coarser and re-test. Its Bambino manual says a grind that looks like powder and feels like flour between your fingers is too fine.
- Use less coffee. Sage’s optimum dose is 8 to 11g for a single basket and 16 to 19g for a double. An overfilled basket slows the water down. The Barista Express comes with Sage’s Razor tool for trimming the dose level after tamping.
- Don’t over-tamp. Sage suggests 15 to 20kg of pressure. Leaning on the tamper with your full weight can choke the shot.
- Unblock the basket. Sage says a blocked filter basket can also stop espresso flowing. Its fix is to clear the holes with the pin on its cleaning tool, or soak the basket and portafilter in a cleaning tablet solution for about 20 minutes, then rinse well.
- Think about the roast. Very dark roasts taste more bitter by nature. If your shot timing is right and it’s still too bitter for you, try a medium roast before changing anything else.
Who it isn’t for: anyone using pre-ground coffee in a pressurised basket. You can’t change the grind, so focus on dose, cleaning and the beans you buy.
Clean the machine: oils and scale both cause bitterness
Old coffee oils in the group head and basket go stale and add a burnt edge to every shot. Scale inside the machine slows the flow. Both are easy to rule out.
- Rinse after every shot. Sage says to rinse the filter baskets and portafilter under hot water straight after use, and to run water through the empty basket to keep the holes clear.
- Run the cleaning cycle. On the Barista Express, Sage’s cleaning cycle uses the supplied cleaning disc and one cleaning tablet in the single basket. You switch the machine off, then hold 1 CUP, 2 CUP and POWER together for about 10 seconds, and it runs for about five minutes. On the Barista Express Impress, Sage says to hold the same three buttons for 3 seconds.
- Watch for the prompt. The Bambino Plus flashes its 1 CUP and 2 CUP buttons alternately after 200 shots to say a cleaning cycle is due.
- Descale. Sage lists “machine needs to be descaled” as a cause when espresso only drips. Our guides to descaling a Sage Barista Express, a Sage Bambino and a De’Longhi Dedica take you through it.
Who it isn’t for: anyone who’s just bought a new machine. If it’s only a few days old, look at grind and dose first.
Machine-specific notes
Sage Bambino and Bambino Plus
Sage says the shot should start after 8 to 12 seconds of infusion and pour like dripping honey. Later than 12 seconds and dripping means too fine. See our Sage Bambino review.
Sage Barista Express
Its troubleshooting table lists the causes of a slow or dripping shot as coffee ground too finely, too much coffee in the basket, tamping too hard, or a blocked basket. Go one step coarser on the dial at a time.
De’Longhi Dedica EC685
De’Longhi’s table covers coffee that comes out too slowly with dark froth. The causes it gives are coffee pressed down too firmly, too much coffee, a blocked boiler outlet or filter, coffee ground too fine or damp, and limescale. Its fixes include pressing less firmly, using less coffee and using only pre-ground coffee meant for espresso machines. See our Dedica EC685 review.
Who it isn’t for: owners of bean-to-cup machines. They grind and dose automatically, so look at the grind setting and the machine’s own cleaning programmes instead.
Where to go next
If your shots run fast and sharp rather than slow and bitter, read our guide to sour espresso. Our guide to making espresso at home covers the full routine, and you can compare machines on our espresso machines page.
FAQ
Is bitter espresso over-extracted? Usually. A slow shot, often from a grind that’s too fine or too much coffee, pulls out too many harsh compounds.
How long should a shot take so it isn’t bitter? Sage’s Barista Express guide aims for 25 to 35 seconds. Its chart puts the bitter zone at over 40 seconds.
Can a dirty machine make espresso bitter? Yes. Stale coffee oils and blocked baskets add bitterness, so rinse after every shot and run the cleaning cycle when the machine asks.
Does dark roast coffee always taste bitter? Dark roasts are more bitter by nature. Getting the shot time right helps, but a medium roast may suit you better.