An Etymological Dictionary of the German Language/Gischt

by Friedrich Kluge

Gischt, older Gäscht, m., ‘yeast, foam,’ formed from the equiv. MidHG. jëst, gëst, m., corresponding to E. yest, yeast, Du. gest, ‘yeast.’ Allied to gischen (MidHG. gischen), older gäschen (MidHG. geschen, a variant of jësen). See gären, a factitive of MidHG. jësen.