Beber vs. beberse
This article explains the difference between the Spanish words beber and beberse, both of which mean to drink.
Beber
A1Beber is a general verb meaning to drink. It describes the action of drinking without emphasis on consuming the entirety of the liquid.
Quiero beber agua.
(I want to drink water.)
Voy a beber un poco de jugo.
(I am going to drink some juice.)
Ellos suelen beber café por la mañana.
(They usually drink coffee in the morning.)
¿Quieres beber algo?
(Do you want to drink something?)
Beberse
B1Beberse is a reflexive verb meaning to drink up or to drink entirely. It emphasizes that the person drinks every last drop of the liquid.
Ella se bebió toda la leche.
(She drank up all the milk.)
Nos bebimos el vino en la fiesta.
(We drank up the wine at the party.)
Él se bebió el jugo en un solo trago.
(He drank up the juice in one gulp.)
Me bebí el agua después de correr.
(I drank up the water after running.)
Summary
In summary, while beber refers to drinking without necessarily finishing everything, beberse emphasises drinking everything until it's gone. The examples make it clear that beber is used for drinking in general, whereas beberse is used when someone has drunk all of the liquid completely.