hey there, nothing wrong on your end. I've tried a few different cold brew makers with the mesh filter immersion method and i also get tiny grinds sneaking through as well. If you're picky (like me) and want the cold brew to be clean and crisp, try spending an extra 5-10 min to pour your coffee through a wet napkin. This will catch a lot of the tiny grinds and its much quicker than pouring the coffee through a paper filter.

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I use the takeya cold brew pitcher, and after brew time is done I'll pour the coffee out into a couple plastic containers, then soak small napkins and place it on top of a funnel and pour the coffee back into the large container. Get any funnel out there, it'll also help when you pour coffee grinds into the mesh filter.

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