I had a Swiss Gold coffee filter a few years ago, and I used it several times w/ regular grind coffee. I always had grounds/sludge in the bottom of the pot.
I gave away the Swiss Gold and went back to paper filters, but I'm trying to economize and "go green," so I thought I would try one of these again and just learn to live with the grounds in the pot, or maybe strain them out with a tea strainer when I poured from the carafe or something.
So, I ordered this Frieling Gold Coffee Filter last week, and the holes in it are smaller than on the Swiss Gold. Guess what: NO GROUNDS IN THE POT! NO SLUDGE!
If you use a fine grind, I would guess you MIGHT have some grounds get through, but with a regular, commercial grind, no problems. In the morning, I just want my coffee quick, and I either use commercially prepared regular grind coffee or grind my own on medium.
I have a Krups coffee / espresso "combo" machine.
Submitted by "Mrs. Neighbor John"