No, you don't need to use any paper filter with Soulhand cold brew dripper because it has a permanent stainless steel filter. As long as you use medium grounds, it will block most of them. If you use a grind size that's too fine, some particles will reach the cup. However, we found they settle at the bottom of the cup, so as long as you don't drink the very last bit, you won't get a chewy coffee.