Perhaps you should try vegetable shortening instead of lard? Crisco.
It would keep your soaps vegan, and the soaps last a lot longer - and don't end up with a grease smell eventually.
I have alot of soaps both all vegetable based, and with animal oils. . . I have seen DOS in both, and have some of each that are well over 2 years old that have not gotten DOS. . .
So it really does not matter if soaps are made with animal oils or not, DOS can be evident to either. . .
The only formula I have made that did not get Dos was one with animal oil, however I Did add vitamin E to the batch.
I do believe that how soaps are stored, really has a big part in the developement of DOS. . . . All the soaps I made in the winter & spring, were stored in a room that had no air vents (no heat, no a/c) All were fine. The same thing when I made soaps near summer - where the temp in this room would reach about 90. . . still no Dos. . .
It wasnt until I moved my production & storage to another place, where the humidity nearly destroyed 1/2 of my stock. It was months of having it covered (stacked separately) with cotton sheets that it finally dryed out enough that I could label & shrink wrap it.
I have read that there is no real determination as to what actually causes DOS. . . . but as I said... I do believe it really has to do with storage. . . as well as how hot you soap. . . I have soaped too hot on 2 batches, which traced rather quickly, and both developed DOS. . . LOL that was when I was a newbie. . . I learned my lesson--- I soap alot cooler now!
Bright Blessings!
Angel:wave: