Cooking For Engineers

[R. Gee]

Why do unglazed stoneware (e.g., Pampered Chef) and iron cookware require oiling and heating before use? Alton Brown in "I'm Just Here for the Food" says that cooking oil steadily degrades past the smoking point, about 140 degrees.

If the unglazed stoneware or iron pan is oiled and repeatedly heated for cooking periods, wouldn't the oil degrade (i.e., turn rancid?)

Wouldn't this condition be unhealthy?

I couldn't pry an answer out of Pampered Chef representatives, so really hope that you can investigate and offer a scientifically-based conclusion.

Thank you.

[GaryProtein]

Oil does degrade rapidly after it reaches its smoke point. Depending on the oil, the smoke point can be anywhere from 225F for unrefined canola oil to 520F for avocado oil, so your cooking temperature makes a big difference.

http://www.cookingforengineers.com/forums/viewtopic.php?t=216&start=0

It would seem that unglazed stoneware would be close to sterilized each time you cook with it followed by a soap and water washing. Unglazed ceramics do not absorb a significant amount of oil or water into their surfaces, they are just unglazed. I'm NOT including clay garden pots Alton uses for a couple of dishes I saw him make, which obviously become quite saturated with oil or water. Unglazed ceramics made for cooking do not seem to hold on to enough oil after a good washing, to go rancid. I don't see it as a health hazard.

[DrBiggles]

[R. Gee]

I checked the Pampered Chef website, and gathered that you are supposed to impregnate the stoneware with some kind of fat (not highly flavored), not use soap so as not to add that flavor to the stoneware, and just scrape, rinse, and dry to store between uses. The company does assume that the fat will remain (and therefore permanently "season" the stoneware so it will easily release food).
I still don't understand how the fat doesn't turn rancid. I was given a piece, costing about $40, and would like to use it with assurance.
Ideas? Excepts are provided below from the website:

"Preparing Your Stoneware
"* To season your Stoneware, lightly spray the unglazed, interior surface with nonstick cooking spray and/or bake high fat foods (i.e., refrigerated crescent rolls or cookie dough) for the first several bakings. After these bakings, your Stoneware will begin to season and greasing may not be required.
"As soap can flavor foods that are baked in Stoneware, it is important that you do not use soap or detergents to clean your Stoneware or wash in an automatic dishwasher using dishwasher detergent. Follow these steps for general and deep cleaning:

"General Cleaning
* Allow Stoneware to cool to room temperature before cleaning.
* Soak Stoneware in clear, hot water to loosen baked-on foods.
* Scrape off excess food on both glazed and unglazed surfaces of "Stoneware using the Nylon Pan Scraper (provided with Stoneware) or the Easy Clean™ Kitchen Brush.
* Rinse and dry thoroughly before storing."

Where is Alton Brown when you need him? Thank heavens for you!

Thank you.

[Dilbert]

the fat doesn't turn rancid because it's not fat, anymore.

after heating it essentially turns to coke within the porous clay structure.

[Watt]

[Guest]

Okay, but let's say someone didn't know he wasn't supposed to put these in the dishwasher and has washed them in there ... repeatedly?

A) Do they need to be re-seasoned? Like, before every use/after being washed in the dishwasher?
Do they need to be treated in some particular way before re-seasoning? It's not like they're rusty like an iron skillet would become (THAT was the cleaning girl's fault, not mine!).
C) Does it really matter one way or the other? Is there a danger here I'm not seeing?
D) Do they need to be thrown away and replacements purchased? (I'm guessing that's the preferred Pampered Chef perspective, so I'm not asking them, I'm asking engineers.)

[Guest]

The stoneware is somewhat porous and will retain soap as well as fat. I was advised, by Pampered Chef, that I could sanitize mine in the dishwasher as long as I didn't use soap. Since you have washed yours in the dishwasher with soap, I would suggest running it through the dishwasher with no soap to try to get the soap out of it. Run it through more than once if you want to be sure. Then re-season as if it were new.

[Tuscan Chef]

Good soap are made of fat. After burning they would be very similar to oil.
So if you want to use soap, use soap made by oil and you would not take the risk of getting something different.

[Guest]

Soap is made from fat, but does not contain much fat. Fat is changed from fat to soap in a chemical process. The amount of fat left in the soap is a result of not reacting. It is similar in nature to cooking, which also causes chemical reactions to happen. I have used bacon fat for years to season my iron skillets. The thin coating left after rinsing with hot water has no danger of turning rancid enough to flavor your food. Besides, you should apply new oil after drying anyway, refreshing the oil source for the dish or pan.

[bella23]