CHAPTER IV. 

 THE MOULD-FUNGI. 



lyrOULD-FUNGI usually affect the fermentation industries in 

 a somewhat different manner from bacteria. Whilst the 

 latter (regularly in distilleries, only exceptionally in breweries) 

 make their appearance in great force during the fermentation, 

 and are therefore able to bring about important changes in 

 its course, and in the resulting products, mould-fungi, on the 

 contrary, usually occur outside the true field of fermentation, 

 selecting as their habitat the vessels, tools, rooms, the green 

 malt, and the quiescent masses of yeast, especially top- 

 fermentation yeast. The mould-fungi, therefore, while possess- 

 ing vital importance, usually act a subordinate part. If we 

 closely examine a growth of mould which has developed on the 

 ceiling or walls of a fermenting room, or on the sides of a 

 vessel, it will soon be found that we have scarcely ever to do 

 with a mould growth alone ; in nearly every case bacteria and 

 yeast-like cells are found among the mould filaments. These 

 filaments extend upwards, lifting up foreign bodies which in 

 this exposed position are more readily carried away, partly by 

 workmen, and partly by the air. 



During malting, all sorts of micro-organisms are present 

 on the raw materials. The mould-fungi are usually regarded 

 as the most dangerous enemies, but this is certainly due 

 to the fact that they are visible to the naked eye during 

 development, and thus obtrude themselves upon our notice 

 in an unmistakable manner. If, however, mere numbers 

 are taken into account, bacteria, which are always present in 



