Reusing kitchen fat

[goji_fries]

The following links seem the most helpful:

http://skeptics.stackexchange.com/questions/8461/is-it-unhealthy-to-reuse-cooking-oil

http://whatscookingamerica.net/Q-A/CookingOil.htm

The first site has links to other sites for information while the second site (albeit old) gives an expanded view on the one source without a hyperlink. Interesting stuff imo.

I would assume that internal would be worse, but because they are fat soluble, they might be retained in skin. IDK either. That's one to read about when I have a free minute... which sadly sounds like CHristmas holiday.

Looks like rancidity starts the dangerous process. But still this is going to be used externally and not internally. Also, a person wouldn't be trying to use rancid oil (dos smell) in a new batch.

I think the soap chemist aka caveman may have soemthing on this one.

 

[dosco]

Nevada: "Ingredients: Prepared from lard and hydrogenated lard, bha, propyl gallate, and citric acid added to protect flavor."

Hydrogenated is good (at least for shave soap) because it converts some of the FFAs into stearic acid. The other stuff I will presume is hydrolyzed or otherwise destroyed by the hydroxide during saponification.

If I used leftover kitchen grease from the fryers at a local restaurant that was known for its sustainable practices, I would have a story.

What kind of oil is it? Is it suitable for soap?

Cheers-
Dave

 

[DeeAnna]

FFA = free fatty acid.

Stearic acid is a saturated fatty acid. If it's not attached to a fat molecule, it is by definition already a FFA. Hydrogenation doesn't affect saturated fatty acids, whether free or not.

What I think you might have been thinking instead is that hydrogenation is a process that converts unsaturated fatty acids in a fat to saturated fatty acids. This means the oleic and linoleic acids (mono- and poly-unsaturated fatty acids) will be converted into stearic acid (a saturated fatty acid).

 

[dosco]

What I think you might have been thinking instead is that hydrogenation is a process that converts unsaturated fatty acids in a fat to saturated fatty acids. This means the oleic and linoleic acids (mono- and poly-unsaturated fatty acids) will be converted into stearic acid (a saturated fatty acid).

Thanks for the specific and accurate clarification. Definitely what I was thinking of/meant.