Benedict sipped the beer alongside his brother, Mgr Georg Ratzinger, and received a gift basket that included pretzels.
The retired pontiff was born on April 16, 1927, in southern Germany. But since the birthday coincided this year with Easter Sunday, the occasion was celebrated on Monday.
On a sunny, mild day, guests sat outside the monastery on Vatican City grounds where Benedict has lived since he became the first pope to resign in 600 years.
