At 14 - minors are allowed to consume and possess undistilled (fermented) alcoholic beverages, such as beer and wine, as long as they are in the company by a Custodial Person. (§ 9 JuSchG (2) Sub-Clause 1, No. 2)
At 17 - minors are allowed to consume and possess undistilled (fermented) alcoholic beverages, such as beer and wine without their parents or a Custodian. (§ 9 JuSchG (1) 2.)
At 18 - having become adults, people are allowed access to distilled spirits, beverages containing distilled spirits, and food products containing non-negligible amounts of distilled spirits. (§ 9 JuSchG (1) 1.)