Folks, I'm brazilian and a homebrewer beginner and I can say that Choop is far form being a beer style, it is just an unpasteurized pilsner served on tap, and as far as I know the word Chopp came from a German volume unity equivalent to 300 ml.
The word chopp on the BRAHMA CHOPP brand doesn't imply that the beer in this case is unpasteurized, actually if it comes in bootle it is, although they have their chopp version as well on tap - unpasteurized pilsner.
I totally agree with the folks here pointing out that the avarage brazilian brew industry deserves no more than one star, however the craft and home brew culture is sailing and today it is possible to find much better beer on supermakes shelves not to mention the pubs and brewpubs that are sprouting in most big cities - I myself have a - dream - project to set up a brewpub.
I also have to admit Brazilians don't understand beer the way it is perceived in Europe or America, we (they) undestand beer as ice-cold pilsners, but we need to look back to history to understand that until few year ago you couldn't find almost anything else - except from few Bock or Malzbier styles.
Chopp is indeed a cheap and unspectacular beer but due its freshness it is, at least, slighlty better than the avarage shelf beer that taste sometimes recycled toilet water.
All I can say is that it is changing for good and fast. Luckly, I live close by an excellent brewpub and go there often and they serve there an excellent variety of first-class ales.
Lagom Brewpub.
I have worked in pubs both in Brazil and England and althought I'm inexperienced about brewing I know this industry from insideout from both sides.