Why does water remain in the bottom chamber after brewing with a moka pot? We are new owners of a Espress Nero four cup Moka Pot by Vev-Vigano.  We have followed instructions from print sources, on-line articles, and YouTube videos and have yet to see reference as to why the pouring pot is only half full while the boiler still has water in it when the pot starts to gurgle.

Why does some water remain in the bottom chamber of the moka pot after brewing?
This is deliberate.

In a moka pot, the downward spout of the funnel does not reach all the way to the bottom of the pot. Brewing will stop once the level of water in the pot falls below the bottom of the funnel (if you carry on brewing after this point, you'll be making coffee with the superheated steam, which will be burnt and bitter).

I'm not sure why this is how it works, but I guess it's to prevent the pot from boiling dry, and retaining a thermal mass in the bottom pot to help it cool down again.



Original image from Wikipedia article on moka pot, thanks to user Alborzagros!