Sour Espresso

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by David6FL »

I am at a loss. I am getting sour undrinkable shots. I have not changed anything that I can identify. I am using the usual beans I purchase from a local Italian market and 18 grams of coffee in a VST 20-gram filter. I pull 1.5 oz in 26-28 seconds. I am also getting wet pucks that I never had before. My machine is a Quick Mill Andreja Premium. Could it be time to replace my grinder burrs? I have a Rossi RR-45. I grind about 1.5 lb of beans a month, I know it's been at least 5 years since I changed burrs.

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Team HB

#2: Post by Jeff »

Grinder burrs dulling seem like they would be a slow process under home use, not a "few weeks" kind of thing. As I recall, the Rossi RR-45 uses 64 mm burrs, so they probably last "years" under home use. The similar-size Mazzer Super Jolly burrs are said to have a 440 kg expected life. At 1 kg/month, that's decades.

Wet pucks, by themselves, aren't an issue. That things are different suggests that the way the extraction is proceeding near the end of the shot is different.

I'd try a couple things to try to narrow things down.

Deep clean the grinder. I'd use some brushes and a vacuum cleaner. Use a vacuum cleaner that is small enough so that when you discover you've sucked up something small and important, going through the bag won't be a terrible task. Try to keep grinds and dirt out of the body and collar threads. I'm not a fan of Grindz or rice for a variety of reasons.

Try a different coffee. Coffee is an agricultural product, that is then often hand processed. Every batch is a little different. Sometimes a lot different. The better blender/roasters do a good job of keeping it reasonably consistent batch after batch by varying the blend and roast profile over time, but there are still differences.


#3: Post by rapha »

Sounds like under extracted shot, your dose + timing should be good enough though. If you're getting the beans from an italian market, I guess the beans are quite dark? I don't believe the Quick Mill Andreja Premium has a PID but if it has one, I would try to get the temp higher. Have you tried beans from somewhere else to compare? I would not worry about the wet puck.


#4: Post by rapha »

Also, did you change your water by any chance? If your water is softer than before, it could underextract the coffee.

David6FL (original poster)

#5: Post by David6FL (original poster) »

For a year or more I have been using the water suggested by Whole Latte Love; Deionized water with the addition of sodium bicarbonate to neutralize the small amount of acidity in DI water and magnesium sulfate to add taste to the water.


#6: Post by rapha »

We can eliminate this factor if you didn't change your water recently.


#7: Post by emradguy »

I would think carefully about the timing of the taste change to purchase of a new batch of beans from your source. It would be the most likely culprit, especially if the taste change came about abruptly.


#8: Post by GDM528 »

David6FL wrote:I am using the usual beans I purchase from a local Italian market
Can you elaborate a bit on the roast you're using? Light/medium/dark/dry/shiny? Perhaps you've noticed a shift in the appearance of the grind? Appearance may not be conclusive, but could hint at the propensity for the roast to go off the rails.

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BaristaBoy E61

#9: Post by BaristaBoy E61 »

Might the water temperature at the puck be too low?
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"


#10: Post by Sandyr10 »

Do you use any tools to distribute grinds evenly in the basket prep?