Why do some home espresso machines have a steam wand with a sleeve over it and a tiny hole in the side of the sleeve?

Why does a home espresso machine (even a 15 bar pressure one) often not produce the same silky micro frothing milk as a professional machine?

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    Tom, welcome! Our sister site Coffee SE is probably the better place to ask this. Usually, it would be up to you to ask wherever you like, but in this case, we have kind of a mutual agreement, so this may be migrated by our moderators. And with a bit of luck, there might already be a set of answers available over there. We'd love to keep you as active user here on Seasoned Advice nevertheless!
    – Stephie
    Apr 3, 2017 at 13:58

1 Answer 1


I was going to put this in a comment because I believe I am relying on conjecture a bit too much but I ran out of space.

Everything I have read online indicates the air holes are various ways to idiot-proof the steam wand and make it more consumer friendly. On my old Delonghi EC 155, it had 2 air holes that were used to help incorporate air into the milk. A common modification of this machine was to replace the entire steamwand with a wand from a higher end machine that lacked all the air holes / plastic contraptions.

A big hindrance to microfoam is the air holes mentioned, or simply, a poorly designed wand tip. There are videos online of people producing high quality micro foam on the Delonghi EC 155 with a modified wand.

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