So, I had to stop by my office today, and thought that I'd get the Aeropress, that I'd bought for use there, back home, since we've been closed for 8 months or whatever it is now, and my home one is starting to wear a bit. I got it out of the drawer, where it has been untouched, as far as I know, for eight months and I saw that the rubbery bit was wet, with droplets on it - hm, someone has been using it, like, 10 minutes ago, I thought to myself, in that incisive way that I have. I picked it up - the droplets were goo. Evidently, plasticizer leaching out??

Makes you think. Does every cup of Aeropress contain just a bit of plasticizer then? Kind of puts me off.

Here it is after rolling around in the back of the car on the way home. Beats vacuuming I guess:

pGolay wrote:Evidently, plasticizer leaching out??

This has come up before. The thought was that it is coffee oil. I had a seal that oozed the stuff. I didn't do a chemical analysis but the goo was consistent with coffee oil in terms of color, viscosity, and freezing point.

So maybe not plasticizer but still kind of gross. My seal never got better so I replaced it. They're inexpensive. The Aeropress is wonderful but the plastic and especially the rubber seal (which seems to always smell like an old car tire) makes it less than ideal. A better solution is possible I suspect.

Aeropresses now use a seal made of silicone. The seal's composition was changed from thermoplastic elastomer to silicone around when the Aeropress Go was announced.

I prefer the new seal. The newer seal seems to have less friction against the Aeropress cylinder. However, I haven't used the new seal long enough to say that there will be no goo.

That's good to know they finally got around to switching to silicone. What took them so long?? It sounds like they are backward compatible to older Aeropresses. I'm going to order one. My current Aeropress seal is so stiff that it takes more strength to use than my Robot.


Here's (one of) my gooey seals. I'd wash it clean and then the stuff would reappear over time, even without use.




I took some of the goo and refrigerated it and it became very stiff at refrigerator temperature (approximately 5°C in this poorly focused photo). That's the goo standing up on its own on the end of a toothpick. The freezing point of coffee oil is approximately 6°C.

I know that it is supposed to be coffee oils, but I still don't like it!

jpender wrote:... It sounds like they are backward compatible to older Aeropresses. ...

Yes, definitely compatible - when I got my Go, I took the silicone seal off and checked it on my old Aeropress.

The first time I got the goo a few years back, I also had scratching in the cylinder and Aerobie kindly sent replacements. (I was told that the scratching was caused by coffee grounds stuck between the seal and the cylinder - so a user error that Alan Adler decided to cover anyway .) With the replacements, I stopped using the inverted method and the goo didn't come back. (I only use the Aeropress when travelling - about 50 cups a year - although not this year.)

My old seal did get harder to press over time. Alan Adler's suggestion was to use a bit of Chapstick on the (pre-silicone) seal. That helped a lot.

baldheadracing wrote:(I only use the Aeropress when travelling - about 50 cups a year - although not this year.)

My old seal did get harder to press over time. Alan Adler's suggestion was to use a bit of Chapstick on the (pre-silicone) seal. That helped a lot.

Me too, it's almost exclusively for travel, something I hope to do again before the end of 2021.

I also don't like the idea of the goo because it could also contain dissolved elements of the stinky seal. Probably not a huge health risk but unnecessarily gross. I'm not sure I want Chapstick in my coffee either though!

I was a bit taken aback at the suggestion of Chapstick initially.

However, it is already on my lips every winter so I am already consuming/absorbing Chapstick (or similar).

I also found that it is a very little amount of Chapstick - just enough to cover the edge of the seal. I had to put it on every third-fourth cup.

So far, I haven't felt any need to use Chapstick with the silicone seal.

Thanks y'all. Seems unlikely to me that it would be coffee oil, but I was wrong about coffee stuff once before.... colorless from what I could see, the press was only used once a day for a few months before the shutdown, washed every time, and the biggest concentration was on the back surface of the seal. Anyway, I've ordered a new silicone one...

Well, who knows? But Alan Adler, the AP inventor, had some "goo" analyzed and reported that it was mostly coffee oil.

https://www.coffeegeek.com/forums/coffe ... 058#662058