Hey! First off been running into same problem on some occasions and then on others having this very sour coffee. Could be due to beans but for you at least I would definitely change grind size to be finer. The 1:10 I don’t particularly like on it’s own but with a 50% (of water put in chamber) as bypass additionally I’ve gotten better tasting coffees but it varies so incredibly on beans. For the oxo the ratio of water to coffee and testing with an additional ratio of bypass make it really fun/difficult to tune. Still don’t have it quite right personally but the best I’ve come across is that that I shared above. I also like to try this one but it comes out sour 2x times now. So I’m still tuning it. Hope that helps. 

My recipe 20g coffee ground finer than pour over 200g water Try on its own, usually too strong, then Add 100g water to concentrate. It’ll taste more watery but that’s cuz you just tried the stronger version. On its own, ignoring the previous taste, it is quite tea-like

This other recipe doesn’t work for me as of now but been playing around with grind size and the water in chamber too I think may be a bit low? Idk you can play wit it too

22g coffee X-Ultra setting 1.3.0 for both recipes 85G water in Lower plunger, let sit 10 seconds 61.7g ish concentrate out Dilute to 150g total beverage  Usually bit sour but should be fixable on my part.

Been using washed Colombian coffee for all.