Yeah, that part about letting it sit too long rings true. My friend Sam had a similar thing happen last week. He was making pour-over and got a phone call, so the bloom went on for like five minutes. When he finally poured the rest, the coffee tasted super sour and kind of empty, just like you said. He couldn't figure out why his usual beans tasted off until I mentioned the bloom time. Now he sets a timer on his phone every time, and it's made a HUGE difference.

A mixing drill is a total game changer.

Always pack extra clips too, just in case.