Please help me, how much brine is needed for an 18-lb turkey?

Enough to cover it.

Yes, you don't like that answer, I can tell already.

But we can not be more exact because we have no idea what you're brining it in and how you'll keep it chilled for the brining period. If you had a sturdy tight fitting water tight sleeve, a couple of quarts would do it. If you're like me and doing it in an ice chest, I need a couple of gallons.

Look, brine ingredients are cheap. So just keep mixing up more as needed until you've got it covered.

When I brine a big turkey, I have to do it in an ice chest. I just don't have room in my refrigerator for a BIG pot or bucket full of turkey and brine. I mix up the brine a bit strong and add ice to keep it cold for the brining period, knowing that the brine will thin out from the melting ice. Then the ice chest lives in the garage overnight where temps will be a bit above freezing usually at that time of year.

Good luck.

Oh yeah- and if you're gonna follow Phil's ice chest strategy maybe wipe it (the chest, not the turkey) out with a little bleach/water solution first. Not nuclear strength- maybe 1 tbsp. in a quart of water would be plenty.

Put turkey in whatever you are going to use as a brine container. Add water to cover. Remove turkey and mark liquid line on the container. Use fresh water in the same amount it took to cover the bird to make the brine. I have a food grade 5 gallon bucket that is used only for brining. I have several lines on it for different sized turkeys, another set of lines for chickens(when I smoke chicken I do a lot at one time), and another set of lines for brining fresh pork hams for cured ham.

As a rough rule of thumb, you want at least as much brining solution by weight as the meat you're going to brine. In the case of an 18 lb turkey, 2 gallons of water (16 pounds) is about right for a minimum. As already said, you need enough brine to fully cover the bird.

1 cup of table salt, to 1 cup of distilled vinegar, to 1 cup of sugar, to 1 gallon of water, is a "standard" brine. The trend in home brining is to use weaker brines, but for brining an 18 lb turkey in 15 hours the standard brine should be just fine.

There's no reason to use kosher salt, although you can if you like. However, kosher salts have different densities from table salt. Here's how to convert: 1 cup of table salt = 1-1/2 cup of Morton kosher salt = 2 cups of Diamond kosher salt. Any time you're brining for more than 8 hours, you want to use un-iodized salt. The iodized kind tends to leave a purple stain.

I find that heating the brining water until the salt and sugar are fully dissolved is well worthwhile. In fact, plan on it.

Don't feel constrained by the vinegar and sugar ratios I gave you. Feel free to substitute wines, fruit juices in amounts that give you the rough levels of sweetness and acidity you'd imagine the standard recipe would give you. For instance, you might want to dissolve 2 cups of salt in 1 gallon of water, remove it from the stove, then add 2 quarts of lemonade, a bottle of wine, and a lot of ice to get the brine cold and ready to go.

If you're brining in a cooler, remember to keep the temperature safe by adding ice now and then.

Any questions, don't be shy. And remember: This stuff is easy.

BDL