Froggy and Soapsap, just went back and checked my notes. Some of the crumbliness in Soapsap's soap *may* have come from the FO although I still think the cutting time was an issue.
If you want to try brine and are concerned about crumbling, I would (a) not CPOP (I still will, 'cause I like it, but that might be an issue depending on your recipe/FO); (b) keep a careful eye on readiness for cutting; and (c) use a well-behaved FO. I think people have reported occasional ones w/the one I had a bit of a problem with (BB's Tobacco Bayleaf). I have not used Ancient Sedona, the one Soapsap did, so don't know if that was a factor.
My oil mix, again, in case that made a difference - Lard 63%, Coconut 20%, Olive 10%, Castor 7%.
Here's my notes on the three brine soaps I did w/r/t FO's (sorry for the big font, cut and pasted from my online notes, having probs reformatting.)
"Additional notes: different results w/heat/hardening on these soaps. Results for all three (CPOP'd all):
Tobacco Bayleaf got very hot and a teeny bit crumbly, though hard on the outside aft @ an hour and cut then though still hot/a bit soft on the inside. Both the Teakwood Cardamom Honey and Cuke Wasabi Cilantro/Bonsai were perfectly hard and unmolded/cut perfectly w/in an hour. FO differences? Unclear."
ETA: The honey in the Teakwood Cardomom Honey blend was a well behaved FO, not actual honey, which I might avoid here b/c of the additional sugar and resulting additional heat if that is a problem for you.