What causes sticking and what can I do to reduce food sticking to my cast-iron skillet?

The first rule to keeping food from sticking to cast-iron is to keep it well primed - it sounds like you're doing that already. Beyond that, read these tips for cooking with stainless steel - they'll also apply to cast iron.

To summarize:

• Food sticks when chemical bonds form between the food molecules and the metal.
• Very hot oil helps to reduce sticking by instantly and continuously heating the food until it's surrounded by a layer of steam from its natural moisture content boiling. Let the oil get nice and hot before adding food.
• Very hot oil also binds with the pan, so food can't. This is the principle behind priming the pan in the first place.

I have some theories regarding particular problem foods:

• Most of the molecular bonding occurs from proteins. Egg whites are mostly protein.
• Frying potatoes creates surfactants in the oil, which cause oil and water to mix. This reduces the effect of the protective layer of steam. (Some people save and re-use cooking oil -- though it can impart a delicious flavor to later meals, it will also build up surfactants if the same oil is used too many times.)
• Also, keep in mind that acidic foods like tomatoes will break down the protective patina and may make foods stick more readily.

Placing the pan in a hot oven until the carbon starts to burn up is a good start. In professional kitchens chefs never let the pan touch soap and do not wash it in water. They will pure a few cups of coarse kosher salt in the pan, heat it on a hot stove for several minutes until it starts to smoke and then use a towel to move the salt around the pan to scrub the pan as the salt is very abrasive. After the salt is emptied a small amount of oil is spread around the pan evenly. The pan is then put on the burner until the oil burns off. When this happens the pan is usually very non-stick. Some chefs will go through the oiling of pan a couple times to build layers of the oil.

Soap is the worst since it will leave a residue that negatively flavors the food.

Seasonning the pan properly helps a lot. Thin coat of oil. Bake at 550 for 20 minutes. Cool down. Repeat 3 to 5 times.

Then when using it, make sure you give it plenty of pre-heat time before putting the ingredients in it.

I also have problems with eggs especially sticking to my cast iron. I have found that making sure there is enough hot oil in the pan before putting the eggs in helps, as does cooking the eggs at a lower heat.

If you are going to cook something "sticky" like eggs or potato, you need to double-oil the pan. While the pan is cold, spray it with cooking spray. Then, after you heat it up, put another coat of oil in the pan. The cold-oil and the hot-oil should make separate layers that will keep your food from sticking.

I have had this issue to going to recondition as it never did this before. The best method I find it to oil it warm it let it cool completely then turn it back on and cook the eggs. I just cant stand this method as it takes a lot longer to get breakfast on the table.