The speed of the soaking process becomes an issue when a long process has to be adjusted to fit within the tannery schedule. The collagen fibres must return to the original hydrated condition, as they were before drying. The consequence of poor soaking can lead to inconsistent processing within the area of the hide, and through the hide's cross-section. This can cause loss in quality and value of the finished leather. TFL's speciality auxiliaries have evolved to meet the needs of high productivity, yet also to safeguard the quality of the leather in process.
How long should the soak take and how do we know if the soak is complete? This is a good question and it's not easy to give a precise answer as there is no quantitative test which will prove the soaking process. Certainly the stock should be evenly flaccid after soaking but this is a very subjective test. It is largely a question of experience gained from seeing limed pelt and crust leather from poorly soaked raw material. When soaking wet salted hides the salt removal can be plotted by taking Baumé checks every half an hour to check salt concentration and plotting these on a graph against time. When the curve stops increasing for at least 60 minutes one can say that at least the salt content of the hide and the float are in equilibrium and the rehydration is complete as far as salt removal is concerned.
Experience has enabled us to say that as a guide wet salted hides of 22 - 30 KG's may be well soaked using PELLVIT enzyme soaking agents in 4 - 5 hours and hides above this weight in 5 - 7 hours. Small skins wet salted usually no more than 4 hours.