Debunk of Day: Potato Fixes Too Salty Soup
Seems like some old wive's cook's tales just won't die. Like the one about adding a potato to overly salted soup to remove salt and make it palatable. It shows up more than once twice three times four times in the first twenty of Babble's current list of how to fix food failures leading me to think that maybe people aren't actually doing the things they are suggesting.
I mean on the surface, it seems like it should work: the potato sucks up a little water and dissolved salt...why wouldn't it selectively suck all the dissolved salt out of the liquid. (Oh wait, see that's absurd on the face of it...)
Rather than calling bullshit on a crowded twitter—because that just makes people unhappy—I set out to test the theory. I wasn't sure I had a tool better than simply tasting it to check the water but it turns out that my refractometer, which lets me measure the sugar content of fruit, also measures salinity. Who knew?
Not to ruin the suspense but no, potato in oversalted soup does not work.
- Calibrate refractometer with filtered water.
- Pour 2 cups water into pot. Take control sample.
- Add 35g kosher salt and heat until salt dissolved. Take sample #1.
- Add 80g chunk of raw, peeled potato. Simmered gently until potato soft. Take sample #2.
- Control: 0 brix
- Sample #1: 9 brix
- Control: 0 brix (done to ensure clean surface)
- Sample #2: 9 brix
We also tasted the potato and it was definitely salty, perhaps a bit oversalted on the outside though the inside was just about right.
The two samples of salted water tasted about the same.
Conclusion: Adding a raw potato to over-salted liquid does NOT remove enough salt to fix it.
This was a simple thing to test and I always enjoy blowing holes in bad information being spread around so I'm looking for other Old Cook's Tales to test. Got one? Leave it in comments.