Need help dialing in - 40+ shots and everything is still unbearably sour [Fellow Espresso Series 1 + Opus Gen 2]
Hey everyone, I’m hoping some experienced espresso folks can help me figure out whether this is user error, my grinder, the machine, the beans, or some combination of everything.
I’m new-ish to dialing in espresso, but I’ve now pulled around 40 shots and I’m completely stuck. Almost everything I make is extremely sour, sometimes sour with a bitter/harsh aftertaste. I’m still within my return window for the equipment, so I’m trying to figure out whether I should keep troubleshooting or return/exchange something and go with a different setup.
Equipment
Espresso machine: Fellow Espresso Series 1
Grinder: Fellow Opus Gen 2
Current beans: Bodhi Zen from Bodhi Leaf
Bean notes: chocolate, raspberry jam, honey
Roast: medium, listed as 3/5 darkness
Freshness: beans are fresh from this week
Prep / accessories
I originally started using an IMS Competition Convex 20g basket because I thought it would help, but I’ve since switched back to the stock Fellow basket to simplify troubleshooting. I’ve also been using an IMS Big Bang puck screen, WDT tool, level/firm tamp, 18g dose, and a scale under the cup.
Fellow Series 1 profiles I’ve tried
Medium profile
- 18g dose
- 1:2 ratio
- 92°C
- 5 sec pre-infusion at 3 bar
- 25 sec infusion at 9 bar
Light profile
- 18g dose
- 1:2.5 ratio
- 94°C
- 5 sec pre-infusion at 3 bar
- 20 sec infusion at 9 bar
- 5 sec ramp down
Classic 9 Bar profile
- 18g dose
- 1:2 ratio
- 93°C
- No real pre-infusion
- 28 sec infusion at 9 bar
Volumetric offset changes
The Fellow Series 1 was originally stopping shots way short, often around 19–24g out, even when using an 18g dose.
I contacted Fellow support and they suggested adding 20ml to each volumetric offset:
- 1st Offset: 48ml → 68ml
- 2nd Offset: 44ml → 64ml
- Nth Offset: 44ml → 64ml
After doing this, the machine started producing more normal output amounts, but the shots were still extremely sour.
For my latest attempt, I dialed the volumetric offsets back slightly to:
- 1st Offset: 63ml
- 2nd Offset: 59ml
- Nth Offset: 59ml
Shot results / timeline
Here are some of the notable shots I’ve tried.
IMS basket + puck screen, Medium profile
Grind 1.0
Output: about 25g
Time: about 21 sec
Taste: slightly sour, but this was one of the more promising shots early on
Grind 1.1
Output: about 20.4g
Time: about 18 sec
Taste: very sour
This confused me because going coarser gave less output and a shorter shot.
Grind 0.8
Output: 19.3g
Time: 26 sec total, 5 sec pre-infusion + 21 sec infusion
Taste: extremely sour
Grind 1.0 again
Output: 20.4g
Time: 19 sec total, 5 sec pre-infusion + 14 sec infusion
Taste: extremely sour with very bitter aftertaste
At this point, the machine seemed to be stopping way too early.
Manual stop test
I manually stopped a shot at 36g out to test whether the machine was just ending the shot too early.
Grind 1.0
Output: 36g
Taste: still very sour
So the issue does not seem to be only the machine stopping at 20g.
Light profile tests before offset change
Grind 0.8, Light profile
Output: about 31g
Time: around 22–25 sec
Taste: still way too sour
Then the machine suggested grinding finer.
Grind 0.4, Light profile
Output: about 24g
Time: around 18–19 sec
Taste: still way too sour
This was confusing because grinding finer seemed to make the shot shorter and produce less espresso.
Grind 0.0
Result: basically choked the machine
No water/espresso made it out
Clearly too fine
After Fellow’s volumetric offset changes
After changing the offsets to 68 / 64 / 64:
Grind 0.5
Result: slower flow
Output: about 40g
Machine suggested going coarser
Taste: still very sour
Grind 0.8
Output: about 36g
Time: 44 sec
Taste: still super sour
Machine suggested going coarser
This was also confusing because I expected 0.8 to flow faster than 0.5, but it took 44 seconds and was still sour.
Stock basket tests
To simplify things, I switched back to the stock basket.
Stock basket
18g dose
Grind 1.0
WDT
Tamp
IMS Big Bang puck screen
Medium profile
Output: about 41g
Time: about 26 sec
Taste: extremely and unbearably sour
Then I tried the Light profile because it runs hotter at 94°C.
Stock basket
18g dose
Grind 1.0
WDT
Tamp
IMS Big Bang puck screen
Light profile
Output: almost 44g
Time: about 26 sec
Taste: still very, very sour
For the latest attempt, I dialed back the volumetric offsets to:
- 1st Offset: 63ml
- 2nd Offset: 59ml
- Nth Offset: 59ml
Then I tried:
Stock basket
18g dose
Grind 1.0
Light profile
Output: about 44g
Time: about 26 sec
Taste: still very sour
Where I’m stuck
At this point, I don’t know what the main problem is.
Some things point toward needing a finer grind because the shots are sour and the beans are a fresh medium roast. But other things point away from going finer: 0.0 completely choked the system, 0.4 produced less output and still tasted sour, 0.8 after offset changes took 44 seconds and was still sour, and the machine started suggesting going coarser.
With the stock basket, 1.0 grind, and Light profile, I got about 44g out in around 26 seconds, which seems like it should be at least somewhat drinkable, but it was still extremely sour.
I’m honestly pretty frustrated because I’ve tried around 40 shots and feel like the grind changes are not leading to clear improvements. I’m not expecting perfect café-quality espresso right away, but I’m surprised I can’t get even one balanced, drinkable shot.
I’d really appreciate open feedback on what you would do next. I’m trying to figure out if this sounds like a grinder issue, a machine issue, a coffee/bean issue, a puck prep issue, or if I should return anything while I’m still inside the return window and move to a more beginner-friendly setup.