I felt the need to report this more out of novelty than pure savoriness, but I think it deserves a mention. Today at Huarches Azteca (5225 York Blvd), among the half dozen homemade, and out of this world, aguas frescas was one I hadn't seen before which was a really beautiful yellow color with reddish brown sediment which was of course stirred well before serving. The waitress told me that it was fermented pineapple, so of course I had to try one (they have regular pineapple as well).
From wikipedia: The tepache is a drink made out of pineapple cortex, some piloncillo or brown sugar and sometimes beer.
It is a drink known since prehispanic times in Mexico [...] Tepache doesn't have a high quantity of alcohol, since it is left to ferment around three days. The alcohol in it comes mostly from the addition of beer, being this the most common way of serving it in Mexico."
And the taste? Well, a lot like you'd imagine slightly fermented pineapple to taste, I can't think of a better description. I didn't detect any alchohol, but maybe if you had 4 or 5... It was good, though not exactly to my taste, I think I'll stick with the melon and regular pineapple, but I still score it a win for Huaraches Azteca, for my money the best antojitos in LA by a longshot (this place drips with unpretentious authenticicity).