Milk in place of water What would happen if one were to substitute milk in place of water for the following brewing methods:


Percolating/Moka pot; 
Pour over; 
Aeropress; 
French Press


Would it extract anything from the coffee grounds? Would it create something passable?
Attempt 1

For the first attempt, I brewed it exactly like I brew my normal (water-based) coffee. I used a French Press with a light/medium roast, heating the milk in Pyrex in a microwave. The milk heated unevenly, curdling in places. Luckily, the curdled bits stuck to the Pyrex and I was able to make a passable cup. The thickness of the milk meant that it didn't want to pass through the mesh when pouring.

The predominant flavor was that of the milk. I could barely tell it was coffee, though it definitely absorbed some flavor. The texture was about what you'd expect--very smooth and rich. It was the kind of drink that makes you feel all warm and fuzzy inside.

Attempt 2

From my first attempt, I learned that milk is able to absorb and mask coffee's flavor incredibly well (after all, it's what people use to tone down overly strong coffee). This time, I heated the milk in a saucepan over low heat, stirring frequently (a rather long and annoying process for a single cup of coffee). I probably could have gotten it a bit hotter, but it worked well enough. I nearly doubled the amount of grounds and brew time.

This time, it came out with a distinct coffee smell, and about the same texture. Again, the initial flavor was that of the milk, but it had a smooth, subtle, and quite pleasant coffee aftertaste. I never got that bad taste you sometimes get a while after a normal cup of coffee--instead, the residual flavor was like you had just taken a sip.

Conclusions

I wouldn't want milk-brewed coffee for my morning cup. It feels more like a drinkable dessert.

If anyone else wants to try this, I recommend using some stronger/darker coffee. I didn't have any dark roast on hand, or I would have tried it. Give it time to brew--more than you would with water. Be patient when heating the milk, or you'll end up curdling it and ruining the whole thing.

This could probably work as a dessert drink if brewed with some spices in addition to the coffee. If nothing else, I'd say it looks pretty cool as you can see in the attached image.

UPDATE

I tried this again today with espresso coffee (Cafe Bustelo), and it turned out great. The end result was like a latte but more... dull, or smooth. I don't know how exactly to compare it. Espresso grind is definitely the right choice when brewing with milk--it's the only thing strong enough and with the right flavor profile to stand out in the milk and complement the milk's flavor.

Be warned, though, that the fine grind of espresso coffee means you will need to use a paper filter at some point along the way. Sticking a paper filter in a French Press doesn't work because of how resistant the milk is to going through the filter. It seems to jet around the sides, allowing the espresso to slip through.