Conceptual image:  Cooking oil bubbles and burns in frying pan
Food - Drink
Why You Should Never Use Salt In Hot Cooking Oil
By EMILY BOYETTE
Ever wonder why cooks on television wait until after their food is done frying to salt it? You would think salting your food beforehand would infuse flavor throughout, as marinades do for so many cuts of meat — but science says otherwise.
It's preferable to stay away from salting before frying because salt reduces the oil's smoke point. Oils with lower smoke points cannot tolerate high-temperature cooking, which causes food to burn and taste bitter more rapidly when the oils decompose.
While restaurants filter their oil daily, they only change out the oil every week or two. Restaurants keep fryer oil at high temperatures for long periods of time, so it's important that salt isn't present so that, economically, they're not constantly creating impurities in their oil and having to discard it.
The bottom line is: If you're a home cook, it won't make a huge difference whether you salt your food before frying. It's best not to go too heavy on the salt if you're wanting to apply it beforehand, but overall, you'll taste the seasonings more if you salt it afterward — that's the most important part, right?