For water kefir, please check following articles: http://aem.asm.org/content/early/2014/02/10/AEM.03978-13 and http://www.microbiologyresearch.org/docserver/fulltext/ijsem/66/3/1281_ijsem000877.pdf?expires=1499412345&id=id&accname=sgid024651&checksum=1FF42F901FE0567E92029486B8434BBA