What is a bottomless portafilter?

Bottomless portafilters (also known as naked portafilters) look and operate similarly to spouted portafilters. They both have a filter handle, filter head, and filter basket. The difference is that the bottom of the filter head (as well as the spouts) is cut off. As a result, your espresso shot flows through your coffee grinds and filter basket directly into your cup.

Training & troubleshooting

The open bottom gives you a direct view of your espresso extraction. This will allow you to notice and remedy things such as multiple streams, off-center shots, etc. By learning what produces a good shot, you ultimately produce a better espresso coffee.

Cleaner

Not many people think to remove the filter basket and clean the inside portafilter head. If they do, it wouldn't be as often as they should. It is also not as easy to thoroughly clean the spouts and the filter head opening. With a bottomless portafilter, those hard to clean parts are not there. As a result, there is less to clean.

Why use a bottomless portafilter?

There are many benefits to using a bottomless portafilter over a spouted portafilter. The main one is to actually view the extraction from the bottom of the basket to locate channeling or grind inconsistencies.

More crema, more flavor

When pulling an espresso shot, you lose crema when it comes into contact with surfaces such as the filter head and spouts. Bottomless portafilters reduce the number of surfaces your espresso shot travels through. This helps increase the amount of crema in your cup. Typically, the naked portafilters have larger filter baskets that hold more ground espresso coffee. This can result in a better flavor profile. However, it does require a coarser grind fineness because there is more ground coffee.

Any reason not to use a naked portafilter?

There is one situation that we can think of where a bottomless portafilter will not work, which is making 2 espresso shots at the same time. In this case, using a double spouted portafilter will be a better option to use. Also, bottomless portafilters should not be used with pressurized baskets as there will be nothing to show in the extraction AND will spray everywhere.