Trinken vs. saufen
While both German words trinken and saufen can be translated as to drink, they carry vastly different connotations and are used in specific contexts. One is the standard, neutral term, while the other implies excessive or animalistic drinking.
Trinken
A1Trinken is the standard, neutral, and polite German word for to drink. It is the default verb used for any kind of beverage, in any situation, and can refer to both humans and animals (especially beloved pets).
Ich trinke jeden Morgen einen Kaffee.
(I drink a coffee every morning.)
Möchtest du etwas trinken?
(Would you like to drink something?)
Wir haben zum Essen ein Glas Wein getrunken.
(We drank a glass of wine with the meal.)
Es ist wichtig, bei heißem Wetter genug Wasser zu trinken.
(It is important to drink enough water in hot weather.)
Unsere Katze mag es, frische Milch zu trinken.
(Our cat likes to drink fresh milk.)
Saufen
B2Saufen describes the act of drinking alcohol excessively and often quickly, equivalent to binge-drinking or boozing. When used for people, it has a very informal, coarse, and negative connotation. It is also the standard verb for animals drinking, though trinken is often used for pets out of affection.
Die Studenten haben auf der Party die ganze Nacht gesoffen.
(The students were boozing all night at the party.)
Er säuft jedes Wochenende mit seinen Freunden in der Kneipe.
(He boozes every weekend with his friends at the pub.)
Hör auf zu saufen, du musst morgen früh aufstehen!
(Stop boozing, you have to get up early tomorrow!)
Die Kühe saufen das Wasser aus dem Trog.
(The cows are drinking the water from the trough.)
Nach dem langen Spaziergang hat der Hund die ganze Schüssel leer gesoffen.
(After the long walk, the dog guzzled the whole bowl empty.)
Summary
In essence, use trinken for the general, polite act of drinking any beverage in a normal, socially acceptable manner. Reserve saufen for talking about excessive, negative alcohol consumption (boozing) in humans. For animals, saufen is the technically correct term for drinking, but trinken is often used for pets to sound more affectionate.