Usually, when I pose something of a question, or a problem, I do so with the ultimate aim that I reveal the answer. The purpose of a blog is nothing if not to make its writer look smart. And so I do try to have all the answers -- even the wrong ones.
But not today. Today, I wonder about goat's milk.
I'd just like to pause for a moment here, and let that last sentence sink in. *exhale* OK.
In all seriousness, goat's milk is the most consumed form of dairy in the world, favored just about everywhere but the United States. I could go on about its fatty acid profile, its high levels of calcium, or its unhomogenized fat globules -- but I won't.
Instead, I will speculate idly on how goat's milk would steam, and otherwise perform, when used with coffee. In the realm of taste, goat's milk skews a bit towards UHT treated cow's milk, in so far as it tastes rather overtly sweet. Even in its fattier incarnations, goat's milk just doesn't have the same inky thickness that whole cow's milk does.
Thus one can reasonably assume that goat's milk would taste even sweeter when steamed, as some of the sugars would caramelize. How unhomogenized milk would stretch, however, is something of a mystery to me. The fat globules are small enough (the reason why it isn't homogenized in the first place) that I don't think you'd end up with a lumpy latte. Either shake the container first, as you would with any non-dairy milks, or count on the swirling action during steaming to do the work. I imagine it probably would.
Of course, I don't actually have experience with a goat's milk/espresso combination. Nor do I have the slightest clue where one might go about finding a place to accomplish as much. But an interesting item to ponder, none the less.