I've been slowly working my way through all the soap samples I've accumulated over the years. Recently, a couple of samples didn't perform as expected, so I'm curious to have SRP's opinion on what could be happening.

The last two soaps I tried were A&E Asian Plum and Declaration Grooming Yuzu/Rose/Patchouli. People on this forum as well as others rave about the lather for both these soaps - unfortunately I had the opposite experience.

When trying a new soap, I like to bowl lather so that I can better control the water to soap ratio. I take my time, adding a few drops of water when necessary. However, I was unable to build a stable lather with either of these soaps. Even after loading the brush for well over a minute, and barely adding any water, the lather was a thin, watery mess that dissipated almost immediately.

I had slightly better results by face lathering. I was able to build enough lather to shave, but I still needed to load the brush and build lather again between passes.

The A&E Asian Plum gave me pretty bad irritation. The DG actually had an excellent post-shave feel - despite the thin lather, my skin felt very soft and hydrated afterwards.

These shaves were about a week apart, and I hadn't shaved in between. Since this lather problem happened two shaves in a row, I thought maybe something was wrong with my brush (which has happened to me in the past). So after the DG shave I loaded up the brush with MdC Rose and built a lather in the bowl. But within just a few seconds the bowl was overflowing with rich, dense lather, so it definitely wasn't the brush that was the problem. I have enough experience lathering different soaps, including tallow soaps (aside from MdC, most of my favourite soaps are tallow) that I'm pretty certain that my lathering technique is good.

Both soaps are tallow based. Could the samples have gone bad? I only had each sample for maybe a year before trying them. The A&E sample maybe a little longer, but less than two years. But I wouldn't think this is long enough for them to go rancid. Maybe I'm wrong. Any other ideas?

Thanks for your input.