Can shaving soap go Bad ?

[Masterblaster]

Among my growing shaving collection I have had a puck of Crabtree and Evelyn - Nomad shaving soap for more than a year now. It wouldn't fit directly into it's designated shaving mug so I had used a pocket knife to trim back the edge. I then stuffed everything into the shaving mug. There are some dips and holes in the soap around the edges where it fits into the mug.

I use the shaving soap perhaps every two weeks or so. But today I noticed an unusual greenish-gray crusty-like covering in the low-lying spots of the soap. The soap itself has a white or off-white color about it. If I didn't know it was soap, I would suspect that mold was growing on the soap ?

Any comments about this greenish-gray crusty stuff on my soap ?

[Don Barbiere]

Without a picture tough to say but most likely mold. Make sure to leave the bowl open so the soap can dry before you put the lid back on after each use. I would just scrape the mold and keep using it.

[Luc]

Pictures would be good yes. I would suggest to wash those bits off if you are unsure. If the soap get too much exposure to humidity, I would suspect that it can go bad yes. Look at where you store it. Could it be another product that fell on the soap? Do you have a lid?

[Aldershot]

If it's kept dry it will last for decades.

[Masterblaster]

- Just to respond.

The soap is in an open mug in the (well ventilated and not particularly humid) bathroom. It never gets covered.

If it is indeed mold - That seems very odd. How can mold grow on soap of all places ?

I can't do a picture anymore cause I took my shave brush and whipped up some suds with it. If there is still some greenish stuff it's now buried below the lather I made. I'll wait a week or two and see if the phenomenon recurs. If that's the case then I'll try and post a few pictures.

- very weird.

[cymric]

If it is indeed mold - That seems very odd. How can mold grow on soap of all places ?
Bacteria and fungi are far more resilient than people give them credit for. Bacteria have been found whose optimum environmental temperature is like that of boiling water (or even beyond), or in lakes with acidity levels exceeding those of battery acid (pH ~ 1). I once prepared a solution of 0.25 M citric acid to clean my kitchen cutting board with (more or less mimicking a squeeze of lemon juice) at a pH of about 2; when I hauled out the spray bottle a few weeks later, which I'd stored in a cool and dark place, I found large patches of fungal growth inside the bottle.

Observations like these make me far less squeamish about preservatives in products like creams where microbial growth is made far easier, and where human action can mix the surface layers with the as yet unspoilt bulk. That soap is spoilt is far less likely, true, but I certainly wouldn't put it past a lucky critter to hit the soapy food jackpot every now and then.