Definitions of foamy:

• adjective:   relating to or containing gas bubbles
• adjective:   producing or covered with lathery sweat or saliva from exhaustion or disease
• adjective:   covered with or resembling small bubbles as from being agitated by beating or heating
• adjective:   emitting or filled with bubbles as from carbonation or fermentation

  Example: "Foamy (or frothy) beer"