And the API itself seems quite simple and easy to use - so it looks like good access to important data.
Before people start iterating every code variation to hit the API and fill their DBs, I think you can download the data from here: http://www.bls.gov/data/
That said their phone support is pretty excellent, and you'll likely get a direct line to the researcher preparing the data.
Clicking on 'Top Picks' (its a badge but its also a link) got me to here: http://data.bls.gov/cgi-bin/surveymost?cu with some series indicators in it.
Clicked on Food and Beverage, selected some years, added a graph and got back the CPI for food and beverages between 1990 to present.