In cooking, the word dredge means to coat an item of food in flour or breadcrumbs before cooking it.
Dredging with flour is often one of the steps in the standard breading procedure, which is a preliminary to sautéeing or deep-frying.
For example, dredging chicken in flour is one of the steps when preparing chicken piccata (likewise veal piccata). Croquettes or cutlets are also usually dredged with flour before cooking.
Dredging in flour requires the item to have some moisture about it, which is the case with most food items. It's a good idea to shake off any excess flour so that the coating doesn't turn pasty or gummy.
The standard breading technique involves first dredging the item with flour, then dipping it in egg wash, and then finally coating it with breadcrumbs. This works because the flour sticks to the food, the egg sticks to the flour, and the breadcrumbs stick to the egg.
In the photo above you can see that the sliced tomatoes will go into the flour first, then the egg wash, and finally the cornmeal, before going into the pan of hot oil.
Basic Dredging Technique
You'd usually add some seasoning to the flour and breadcrumbs. Salt and pepper are pretty much a given, and paprika, chili powder, garlic powder, and dried or fresh herbs are also good candidates.
When you do this, you'll want to prepare three containers, one with the seasoned flour, one with the beaten egg, and one with the breadcrumbs. You'll also need a dish or pan for the completed items, as well as whatever dish or pan you're pulling your un-dredged items from. Arrange them from left to right in the following order: un-dredged items, flour, egg, breadcrumbs, pan for dredged items.
Now, pay attention to which hand you use for each step. The goal is to use your left hand only for handling the items when they're dry (i.e., before they go into the egg), and your right hand will be your "wet" hand, i.e., for transferring egged items into breadcrumbs and then onto the finished tray. If you get the hands switched around, you'll end up with a gummy mess.
Left hand: Pick up the fresh item and drop it into the flour. Toss it around to coat, then shake off excess flour. Carefully transfer it to the egg bowl without getting an egg on your left hand.
Right hand: Flip the item around as necessary to allow it to be fully coated with egg, then lift it out and let any extra egg drip back into the bowl. Now transfer to the breadcrumbs and, still using your right hand, toss in the crumbs to fully coat, then move it over to your finished tray.
Keep repeating until done. Of course, you can reverse the direction if you're lefthanded, or because of the configuration of your kitchen, or if you're simply more comfortable going the other way. Just keep the be sure to keep the order the same.