Regarding "What Should I Use Instead," hear, hear! I routinely save the fats from whatever meats I cook. I am a big proponent of keeping a big jar of bacon fat in the fridge to cook with, for example. Bacony goodness. Works great for sauteing veggies. Oh, and mushrooms, those wonderful little sponges that just love to soak up flavor. Put a bunch of sliced mushrooms in a pan with bacon fat and a lot of fresh minced garlic and a touch of oregano, then serve them over steak. Absolute heaven.

And to me it is the height of silliness to skim the fat from the drippings of whatever I cooked, and then replace it with butter to make gravy. Turkey gravy tastes a lot more like turkey if you use the turkey fat, for instance, and butter is expensive. The fat from the critter is free, but most people just throw it out. And, whenever I can get to my butcher, I get pork fat to render into lard for deep frying. That stuff you get in tubs in the grocery store is not real lard. I also make schmaltz, for when chickeny goodness is better.

I find it terribly sad that so many of us have been conditioned to say "Eww, fat!" The funny thing is that my relatives, although most of them believe in the low fat thing, still love to come to my house for holiday meals. As long as they don't see how much fat I use, they don't care. My stuff has flavor🙂

I do most of my cooking using pastured ghee in a cast-iron skillet. I'm curious what you think about what happens with the omega-3 content of the grass fed butter both in the process of converting it to ghee and in the process of using the ghee to sautee food in cast-iron.

According to this post on seasoning cast iron iron catalyzes radical polymerization of omga-3 fatty acids. She claims that the best way to season cast iron pans is using flax oil to maximize the creation of a polymerized fatty acid coating -- which is the same process that happens in when the linseed oil in oil-based paint or varnish "dries".

The question is: when cooking with ghee in the cast iron pan, to what extent would the radical polymerization happen at sauteeing temperatures, and to the extent it happens to what extent would the damaged PUFA be safely sequestered away from the food by adding it to the surface of the cast iron vs. leaving damaged fats in your food (either polymerized, trans-isomerized, oxidized)? I do notice that habitual use of ghee does lead to a consistently happy non-stick surface in that skillet!

Thanks,
Anne

I'd be very interested in that experiment, since I do re-use my tallow. I've kind of gone with the idea that, since it's mostly saturated, my metabolism can probably handle what damage occurs from multiple uses, but it'd be nice to have something on which to base the idea (or refute it, as the case may be).

it is impossible to make a trans fat from a monounsaturated fat

Source?

It's impossible to make a trans fat from a monounsaturated fat by hydrogenation: I thought that was clear from the context.

It was clear from the context. You were then asked for a source for that claim. You responded by repeating the claim, again without giving a source. Does simply making a claim make it true?

Let's see what Google says:

Replacements for Trans Fats—Will There Be an Oil Shortage?by DC Klonoff - 2007 -
During hydrogenation of monounsaturated [...] fatty acids in vegetable and fish oils, far more trans than cis double bonds are formed.

Clinical Manual of Total Cardiovascular Risk - Google Books ResultNeil R. Poulter - 2008 - Medical - 88 pages
Trans-fatty acids are usually derived from industrial hydrogenation of monounsaturated [...] fats

Trans Fat, Fat caused by "hydrogenation" of monounsaturated [...] fats

Displacement of the double bonds during hydrogenation of ...by C Boelhouwer- springerlink.com
- 1953
The displacement of the double bond of several unsaturated fatty acid methyl esters during hydrogenation with a nickel-kieselguhr catalyst at 180°C. was investigated. The analysis of the dicarboxylic acids (obtained by oxidation of the reaction products with KMnO4 in acetic acid solution) by means of partition chromatography enabled a reliable semiquantitative determination of the position isomers formed.
During hydrogenation of methyl esters of oleic [...] acid formation of large amounts of position isomers was proved to occur. Migration of the double bonds in both directions took place but was in all cases strongly pronounced in a direction opposite the ester group. [...] It follows that hydrogenation of fatty acid esters leads to products which are far more complicated, as is generally known.

MERCK
Trans fatty acids are usually derived from industrial hydrogenation of monounsaturated [...] fats

[...] they don’t oxidize or polymerize during cooking the way that seed oilsdo, they don’t contain hidden trans fats, and they have low to zero omega-6 fat content. I discourage lard unless it’s from pastured [...]

Wow! Michael Pollan was right once again. In a lecture I attended, he predicted that omega-6 would be the next "bad fat" of fad, which is rather bizarre considering that it is an essential fat.