Bialetti Moka Pot foam differences

Coffee preparation techniques besides espresso like pourover.

#1: Post by Smithereen »

Hi coffee drinkers,

I have a 3 cup aluminum Moka Express and 6 cup stainless steel Musa. Both make great coffee and have been in service for 10 and 5 years respectively. I have a question that perhaps coffee people smarter than me know the answer to...

When I brew in the smaller aluminum maker, the coffee flows out of the spout very slowly, steadily, with a ton of bubbles (foam) - almost espresso-like. With the larger steel Musa, the coffee flows pretty steadily, but sputters a little more, and has hardly any bubbles (which dissipate quickly). Why the difference? I'm guessing something to do with water volume to pressure ratio? Or perhaps the heat conductivity of aluminum and steel?

My recipe for each is the same and pretty standard: near boiling water in the reservoir, slightly coarser than espresso grind, no tamping, just level off the full basket, medium heat on the gas range, coffee is ready in similar times in both pots - about 30-60 seconds... now that think of it, I don't know why this brewing time isn't different given the different sizes...

And just to be clear, the coffee tastes similar and to my liking in both - I don't actually want to change my brewing method - I am just curious as to the difference of foam from each (and I now why the brewing time is more or less the same)