I've never found a need to soak biots in any way but I do reinforce them as I tie. I use the tying thread to chase the biot as you wrap forward , overlapping each wind of biot with a thread wrap. The thread is covered by the next wind of biot. Works for me and do believe it provides an extra measure of durability. I believe this method is from one of A.K. Best's books but don't recall which.

-ParaHopper