Did you read what I linked?
You can only extract tannins by squeezing a bag, IF you produced tannins to begin with. Squeezing the bag doesn't produce the tannins in the grain. It only releases them if they were there. And they are only produced in a narrow range of situations- i.e. the right (or wrong I should say) combination of PH and Heat....otherwise there's no tannins to be released.
We're not making tea, we're making beer. We're not brewing with tea which has a high level of tannins to begin with. We're using grain, and there's little if any natural tannins there to begin with....
The old tea bag analogy has been long shot down..... This discussion is mostly about how people like you misunderstand who tannins get produced, and repeat what you posted.....