Months ago, I participated in a taste test comparing pourover "bloom or no bloom" as the local expert (?!). Admittedly, I'm not a regular Chemex drinker, opting 28 days out of 30 for espresso. But why not? So here's the video:
Somewhat predictably, I didn't correctly identify the outlier while Martin, a pourover fan, nailed it. Last week he mentioned that the other taste test where the outcomes were reversed (i.e., Dan nailed it, Martin whiffed) would publish it this week. Of course, I need to share that result immediately.
Kidding aside, my real point for posting these two videos is simple: If you want to assert X is true, test it blinded. It's fun, and honestly, a little humbling.

Martin was just surprised enough at nailing it to make me think it wasn't a stark difference. So even though blind it could be dumb luck that he got it right.

Do it twenty times!

Haha yes indeed. I'll often perform the triangle test 5 times just to see if it was dumb luck (or bad luck) the first time. These triangle tests are hard!

I did a series of blind tests one time to compare coffee stored in ziplock freezer bags versus coffee stored in vacuum sealed bags. Every test was a close call but (to my surprise) I consistently picked the freezer bag coffee over the vac sealed coffee. When I calculated the odds of this it was 1 in 144.

I repeated the same test and there was no consistency in which one I picked. The first time was just a statistical fluke. The odds of 1 in 144 is equivalent to rolling two dice and getting snake eyes followed by flipping two coins and getting both heads. Unlikely but not amazing.

So I came to realize that blinding isn't enough by itself.

On a related note, see A note on comparison tests for an explanation of the odds of X, Y, or Z.