Some of the strains used for the biological acidification in breweries belong to L. delbrueckii subsp. delbrueckii, L. delbrueckii subsp. lactis or L. fermentum. However, more recent studies showed that most strains isolated are physiologically different from the above mentioned species and were tentatively allocated to Lactobacillus amylovorus. Genotypic studies of 25 strains exclusively isolated from beer malts and beer worts, showed, that there were differences to the type strain of L. amylovorus concerning DNA-DNA similarities and the sequences of their 16S and 23S rRNA genes. Therefore, we propose to combine these strains in a new species of the genus Lactobacillus, namely L. amylolyticus. Strain DSM 11664 is proposed as the type strain. An rRNA targeted oligonucleotide probe was designed that allows a fast and reliable identification of Lactobacillus amylolyticus.