As someone who makes a few drinks at home each day, there are a lot of practical advantages to the bottomless portafilter, mostly centered around the ease both of drying it before the shot and of keeping it clean. When I first got it, I noticed and posted about the difference in texture, though, particularly with Malabar Gold for some reason: the bubbles were much larger and dissipated quickly. By accident, I found the solution, at least for me. I'd been, as was my habit with a spouted portafilter, holding the cup up in the air. When I left it down on the drip tray, so the flow dropped about three or four inches into the cup, the added violence of the flow and mixing when it hit largely eliminated the difference. Simple to try, at least, for anyone who wants to.
Best,
David
