People like to argue about the Brining Question a lot this time of year. Here's my usual response. If you're working with a run-of-the-mill commercial bird, absolutely brine and brine with something flavorful. If you have a heritage bird, still brine, but don't over-do it on the add-ins like herbs and spices. You've paid a pretty penny for a bird whose flavor is part of its heritage: don't cover it up with too many fussy flavors.
But first, for those of you asking "what is brining?" here's a quick definition:
A brine is a solution of salt and water used to pickle or preserve foods. In the case of meats, the solution can help increasing the amount of liquid inside the meat cells; basically it's a way to make the meat juicier.
There are two issues with brining: what to brine with and what to hold the bringing bird in.
First, the vessel. If you have a stockpot large enough to hold the bird with a few inches to spare on all sides, great. Giant enamel lobster pots are great for this. So are coolers and big plastic storage boxes. You can also use a plastic bag. Some use trash bags, but this is risky - one little poke from the turkey's wing and you'll have a huge mess on your hands, and floor and produce drawer and everything else. Ziploc makes a line of large bags meant for storing toys and off-season clothing. The XXL size will pretty much hold any size bird except perhaps an ostrich.
Fire & Flavor makes a bag specifically meant for brining called the Turkey Perfect Brine Bag, which means it talks more about food than sweaters and soccer balls on the packaging. It has just one bag per package, which I appreciate. Less waste. They also make a brining mix, which I'll get to below.
Shirley recommends after you've removed the innards and cleaned the bird, to rub it all over with about 2 cups of salt. Set it in a container large enough to hold it with at least a few inches on all sides, including the top. Fill the vessel with cold water, covering the top of of the bird. You may have to weigh it down with another pot of water; I've even seen a brick wrapped in a plastic bag used as a weight. Store it in the refrigerator overnight, at least 12 hours. While you're setting yourself up for this project, make sure you have room in the refrigerator and that the shelf you're using (presumably the bottom one) is strong enough to hold the heavy load.
Some people get fancier with their brines and add sugar, herbs and spices. There are many recipes floating around for this but my advice is to go by instinct. What flavors do you like? Add them thoughtfully taking care not to overload your bird with too many different notes. Peppercorns, star anise, whole cloves, dried fruit, and lemon and orange peels are often used. If you're making a more involved recipe, mix everything together with about half of the water you think you might need. Pour it over the turkey, then add enough water to cover the bird.
You can also buy a brining mix. Fire & Flavor also makes some nice brining mixes that are conveniently shelved near their brining bags in the butcher section of Whole Foods and other markets.
One final note: Make sure your turkey isn't already brined: kosher turkeys and some brands (Butterball is one) are already brined, so brining yourself at home will make for an inedibly salty bird. In this case, a dry rub might be nice. Another option for adding flavor is to stuff herbs like thyme sprigs, sage leaves or chopped rosemary under the skin before roasting.
• Buy the Ziploc XXL Heavy Duty Big Bags at Amazon ($7.06 for three)