Fermentesco, fermentéscis, fe rmentéscere. Idem quod Fermentari. Plin. To puffe or rise vp by leauening.Fermente scere, etiam tellus dicitur. Plin. To be light and not cogither.
Lewis and Short: Latin dictionary
fermentesco, ĕre, v. inch. n. [fermentum] (lit., to ferment, to rise in fermenting; transf., of the earth), to swell, rise, become loose (Plinian): tellus quoque illo modo (i. e. ab nive diutius sedente) fermentescit, Plin. 17, 2, 2, 15; 28, 8, 28, 109.