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March 20, 2010 7:50 AM

What does soap smell like?

We all know what a clean, "soapy" smell is like, outside of lavender or any other common soap fragrances. You can find it in all kinds of plain bath soaps and detergents. But what is that smell a result of? Sodium tallowate? Saponification itself? I apologize if it's a question that can't be answered, such as "what is the flavor of bubblegum."

posted by Countess Elena to Science & Nature (10 answers total)

Very subjective, but because I'm a big fan of unscented or lightly scented bar soap, I can usually factor out the various scent additives in how I think about the "scent essence impression" I have of bar soap. Generally speaking, bar soap to me smells like the base used for its manufacture, which is some type of vegetable oil or fat ... so ... nice light frothy vegetable oil, or something along those lines, is how I would put it.

This probably grosses people out, which is why most soaps have at least some kind of scent added. (For me, however, it is a good thing because the way some people get freaked out by too much noise, I get freaked out by too much scent. I've had to leave stores that have too many scented products clashing with each other because it sometimes makes me light headed.)

This might be of interest.
posted by gudrun at 8:17 AM on March 20, 2010

Laat year, I had to do a saponification lab in Gen Chem. We made soaps out of lard, crisco, vegetable oil, etc. and I recall that none of them had much of a smell after being reacted and washed off.

I think the smells we associate with soap are just fragrances that are added in.
posted by rancidchickn at 8:21 AM on March 20, 2010

Well, not to get all Dr. Bronner or anything, but most soap is not, in fact, soap (i.e. saponified fats) but detergent (chemicals!!!! oh noes!!!!). The chemical detergents have a chemical smell. Real unscented soap just smells like oil that's gone a bit rancid.
posted by Sys Rq at 8:36 AM on March 20, 2010

Response by poster: Hm, maybe it's the smell of a common detergent I'm thinking about. I have certainly used unscented vegetal soaps, but I had believed that those were not chemically "soap," just cakes of saponified oils, and were only called soap by common usage. I thought that soap per se was a stronger, more alkaline substance. I may be wrong about that.
posted by Countess Elena at 10:50 AM on March 20, 2010

I had believed that those were not chemically "soap," just cakes of saponified oils

Nope. Soap is saponified oils. That's what saponified means: Made into soap. Entomology!

Detergent is commonly called soap because it does the same job in the same way, but it's really just a recently developed soap substitute.
posted by Sys Rq at 11:29 AM on March 20, 2010

Sys Rq is correct in this: Soap in by definition saponified oils. Detergent is commonly called soap because it does the same job in the same way, but it's really just a recently developed soap substitute. Here's a bit on lye soap and laundry in the old days. (except Sys Rq, oops, you meant etymology, not entomology in your comment.)

Countess Elena - Maybe you should be more specific in your question. Are you asking about dish detergent, laundry detergent, bar soap, or what type of "soap" are you really talking about in your question? Here's some general info..
posted by gudrun at 12:23 PM on March 20, 2010

Entomology! Um, yeah...
posted by Sys Rq at 12:25 PM on March 20, 2010

Response by poster: It's hard to articulate because I don't know what produces it. It's the "well-scrubbed" smell you get from freshly washed laundry, generic soaps, and, recently, candles with names like "Clean Linen." That makes me think it is probably a detergent smell, rather than a soap smell.
posted by Countess Elena at 2:43 PM on March 20, 2010

For what it is worth, here is a link to some "fresh linen fragrance oil", which they describe as having "back notes of powder and musk. Very similar to downy fabric softener. Notes include: jasmine, lilac, peony, Egyptian musk and French vanilla."
posted by gudrun at 4:25 PM on March 20, 2010

I used to make soap.

Unscented soap smells like shortening: an empty, barely there smell but vaguely fatty -- and not "fatty" in the buttery or beefy kind of way. It's a one-dimensional kind of smell is the best way I can describe it, rather than a full or rounded smell.

The "soapy" smell you're describing though, is an added scent. There's no one scent that produces that smell, though, and in the case of soaps scented with non-synthetic smells, the soapy smell can vary from person to person based on how their skin reacts with that specific essential oil. Certain kinds of cinnamon and almond, for example, will "turn to soap" on me but not on other people. Other people have this problem with rose smells, but it continues to smell like rose on my skin, etc.

Synthetic smells generally hold their smell regardless of what they're applied to, but not always.
posted by Nattie at 8:28 PM on March 20, 2010