can only recommend the part sufficiently large drain hole ensures brisk filters. That this process towards the end of the brewing process is slower, is normal, since the ground coffee is by then completely swollen and slows the passage of a little, and both with a drain hole as with three drain holes (such a for I have also, and no difference noted) , - There is a difference ... the coffee tastes - so prepared - many times better than the conventional coffee from my (brand device). Janice-Jacquetta
