In a large bowl add in 1 quart of your sourdough starter ( I usually have 1 quart left that I keep in the fridge). Mix in salt and 3/4 cup water. Slowly stir in the 6 cups of flour. You can do a mix of different types of flours. Using all rye flour will result in a very dense bread that some love, but if you want a lighter sourdough then I suggest spelt or some stone ground wheat. Your dough will not be one that you will knead much, it will be thick but not come together in a ball. I work the dough for a bit (5-10 minutes) and then divide into about 3 loaf pans. Cover with a dish towel and let rise over night or for at least 5 hours. I like to do this right before bed and then wake up a little early to bake for breakfast. Bake at 375 for about 40-60 minutes. When you can tap on the bread and it sounds hollow- it is good to go. Let sit for 15 minutes before digging in. Now if you are like me, you won't wait that long and I can assure you it is delicious straight out of the oven. Always eat with a big slab of grass fed butter! I like to slice up 2 loaves and keep them in the freezer. The other loaf should last a week without a problem.