Please find below some ways in order to be a brewmaster :
1) The first option is to do an internship in a brewery without any background at school. You can become an operator/brewing assistant and maybe later a brewmaster.
2) The second way is to study 3 years in food industry school. You can entry directly as brewer in a brewery but not directly as a brewmaster.... (not for a big brewery).
3) There is several school allowing you to be directly a brewer after 1 or 2 years of study. Sometimes a other background is mandatary in order to be allowed to do this school (as engineer degree, biologist, chemical science...).
The most famous one is the VBL in berlin : https://www.vlb-berlin.org/en/brewmaster
It is existing other school depending the language as :
GERM Technischen Universität München : http://www.studienfakultaet.de/
NL Gent universiteit : http://www.researchinflanders.be/en/focus-on-research/the-art-and-science-of-brewing-university-college-ghent-ghent-university/
FR Meurice at brussels : http://www.meurice.heldb.be/index.php/l-institut-meurice/laboratoires-et-services/industries-biochimiques
FR UCL close to brussels : https://sites.uclouvain.be/archives-portail/ppe2013/prog-2013-bras2mc
FR Nancy unversity in France : https://www.cidj.com/metiers/brasseur-malteur
4) To open your own brewery but this is maybe the more risky way... good luck! ;)
Article en version française.