Here's what I use, and its dang good. You can adjust the amounts for breasts. What I do is put the Brest in what ever I am going to brine in and cover with water. remove the breast and then measure the water, that's how much brine I make.
1 1/2 Gallon Apple Juice
5/8 Cup Kosher Salt (5 oz)
3/4 Cup Dark Brown Sugar (6 oz)
1/2 Cup Morton’s Tender Quick (4.5 oz) or 2 Tbsp DQ cure #1 (1.5 oz)
1 Tbsp Garlic Powder ( .3 oz)
1 Tbsp Onion Powder ( .3 oz)
1 Tbsp Cajun Spice ( .5 oz) (Louisiana Cajun Seasoning)
1 Tbsp Celery Seed ( .3 oz)
1 Tbsp Pickling Spice ( .4 oz)
1 1/2 tsp Ground Cloves ( .2 oz)
1. Place all spices in spice grinder and grind fine.
2. Place 4 cups of apple juice in a 4 quart sauce pan, add Salt, Sugar, cure, and spices heat and stir until completely dissolved.
3. Turn off heat, cover, and cool to room temp.
TIP do steps 1-3 ahead of time to allow chilling in refrigerator or freezer.
4. In a large stock pot, combine remaining apple juice with the concentrated brine.