Espresso both sour and bitter?
My first post so hope it's in the right section and abiding by all the rules.
My question relates to a new batch of Tanzanian coffe I got from my local specialty roaster.
The colour was city/dark city roast but only by eye and coffee is 10 days old, so should be in the sweet spot.
My problem is when trying to dial in the shot I could only get a sour start, mild/medium body but a lingering bitterness. Changing grind or brew ratio doesn't help either way results in under extracted sourness or bitter astringency.
Commercial Astoria lever machine
Ceado E37S grinder
91 degrees temp
19 gram vst basket
1:2.5 Brew ratio
5 sec pre infusion
Any thoughts on the both sour and bitter at the same time?