Schweigt stille, plaudert nicht (Be still, stop chattering)
I’ve read that Bach owned a few coffee makers and was a big coffee lover Himself. The consumption of this beverage was apparently illegal during Bach’s time, since the profits for its sales went to foreign hands, as opposed to the profits for beer sales, which would stay in Germany, so the King was rightfully upset about people drinking coffee. This cantata would be Bach’s funny take on the situation I guess, in the form of parody. (From one of the YouTube comments)
From Wikipedia: The Coffee Cantata (BWV 211) is a secular cantata written by Johann Sebastian Bach between 1732 and 1734. Although classified as a cantata, it is essentially a miniature comic opera.
In a satirical commentary, the cantata amusingly tells of an addiction to coffee, a pressing social problem in eighteenth century Leipzig, where this work was premiered.
The cantata's libretto (written by Christian Friedrich Henrici) features lines such as “If I can’t drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat” — a sentiment that would likely have been appreciated by the patrons of Zimmerman’s Coffee House in Leipzig, where Bach’s Collegium Musicum, founded by Georg Philipp Telemann in 1702, would have originally performed the work.
Bach wrote no operas: the cantata was written for concert performance, but is frequently performed today fully staged with costumes.