The value-loss to the tanner from bacterial- activity is evident to the nose, as well as to the eyes. The origins of bacterial attack, how bacteria damage the hide, and how this can best be avoided all form part of the core experience of TFL. Check the section on soaking to find out more.
The presence of blood and dung etc. in warm soak liquors is a major source of bacteria contamination and propagation. The presence of large amounts of dung can cause discoloration of the limed pelt and limed flesh splits, very important if the splits are to be used for the sausage casing etc.. In extreme cases the amount of dung adhering to the hides can materially effect the apparent weight of the hide load.
The control of bacterial growth in soak liquors is of great importance if such problems as nubuck grain and veins are to be avoided. These bacteria will produce enzymes from their digestive processes and among these will be some with activity against collagen and elastin.
This growth in bacteria must be controlled with suitable biocides such as ARACIT grades. Establishing a stable pH between 9 and 10 helps to keep bacterial growth under control.