Nice coffee when brewed but...........

Currently struggling a little with this coffee. Last espresso shot was 20g to 45g (2.25 ratio) in 35 secs at 96°C in a VST 20g basket on the brewtus and super jolly combo, using charcoal filtered tap water (Plymouth water being pretty soft). I just can't seem to shake off the sourness. beans were roasted on 23rd by the way.

I've had some really tasty results with the aeropress doing 15g coffee to 200g water for 1 minute 30 secs off boil) and i'm really liking the coffee this way, but espresso just isn't doing it for me yet. Giàn phơi thông minh

Should I just try grinding a bit finer and extracting to the same ratio which will equal a longer extraction time or should i try a different tack? My mrs tasted one of the 20g-20g shots in 35 sec shots i was going to bin and even then she didnt think there was much bitterness so im struggling to figure out what i can do.

anyone out there have any advice for parameters I should give a crack?

cheers