I watched some videos of coffee blooming using standard Chemex, but my
coffee doesn't bloom like that. As far as I can tell, my coffee isn't
blooming at all. What's wrong?

Does course or fine grounds affect blooming?

What I do is the same as they do. After rinsing out the unbleached filter
with near boiling water, I put the freshly ground coffee into the filter and
slowly add the water as they do, but after watching a number of videos, my
coffee has never bloomed like that. Not even remotely close to that.
However, the coffee tastes better then I could even do in drip maker or
French Press.

What is the secret of this blooming technique? Does the kind of beans
matter? I use standard Columbian beans by bulk, Costco.

Thanks,
GBMT