I think Aeropress is great overall, but I am puzzled why they made holes on the side of the plastic cap where coffee (liquid AND grounds) can come out sideways with no paper filtration. I often get a small amount of silt because of this. I thought the AP founder was a big champion of paper filtration. I also have to be careful not to press too hard because coffee can shoot out through the spout of the metal pitcher it is on and make a mess.

The holes are (obviously) deliberate. They're meant to be a sign that you are pressing too hard, and to prevent clogging by over-zealous users or too-fine a grind.

In the past, aftermarket gaskets were sold to seal the holes for zero bypass. Now people wanting clarity use Aesir filters or three Aeropress filters - not zero bypass, but close.

Not sure how Aesir filter or three AP filters get you closer to zero bypass. It seems to me they offer more resistance, thus more bypass through the side holes, no?

Also, most folks probably won't be able to tell it's leaking sideways because (I think) people typically use a mug and they can't see how it flows. Besides, I think substantial amount (30%?) of coffee is always flowing through the side holes even if you don't press too hard because that's the path of the least resistance. I always get some oil that I don't see with v60. I am not sure I buy their claim that AP filters out the coffee oil (that can increase your cholesterol) as much as they claim to do.

It's hard to tell for sure, but it seems the new flow control filter may be the solution for me.

https://aeropress.com/products/aeropres ... filter-cap

Or https://fellowproducts.com/products/prismo which has a seal.

Thanks. Fellow Prismo and AP Flow Control cap both seem to have a seal. As far as I can tell, another major difference is AP FC allows a straight paper filter while Prismo needs the included metal filter PLUS paper filter if I seek paper filtration.

I don't understand any of the foregoing responses. I have an original Aeropress, which has done hundreds of cups. It has the side holes in question. I fail to see how they serve as a safeguard against over forceful pressing an excessively fine grinds. I've pressed down on mine very hard, many times, while experimenting with different grinds and coffees. Never has any coffee or grinds come out of those side holes. The seal, with only the paper filter as a gasket, is total. Likewise with my metal filter. That said, I too have no idea why Aeropress put those side holes there.

Nunas wrote:I don't understand any of the foregoing responses. I have an original Aeropress, which has done hundreds of cups. It has the side holes in question. I fail to see how they serve as a safeguard against over forceful pressing an excessively fine grinds. I've pressed down on mine very hard, many times, while experimenting with different grinds and coffees. Never has any coffee or grinds come out of those side holes. The seal, with only the paper filter as a gasket, is total. Likewise with my metal filter. That said, I too have no idea why Aeropress put those side holes there.

Interesting. What am I doing wrong then because it's quite easy to get silt in my cup, especially if I press hard in which case coffee literally squirts out sideways and sometimes through the cup spout and make a huge mess.

Hmm...I dunno. Perhaps you don't tighten the cap as much as I do. I give it a good firm twist. The next time I use my Aeropress, I'll put the cap on with less oomph and see what happens.

What's what I initially thought, so I tried tightening really hard but to no avail.