But, if you add too much or too little, problems occur. Using water that potatoes have been cooked in produces a higher loaf of bread. My mother taught me to use the left-over water from boiled potatoes, as the liquid in bread recipes. The cooked potato starch in the water gives a boost to the yeast, making it rise faster and also adds sweetness. Store your potato water tightly covered in a refrigerator and it will keep for 3 - 4 days.
Milk gives bread a more tender crust than water.
You can use instant dry milk powder or dry buttermilk powder found in the dry and canned milk area of your grocery store. I like to fresh milk and buttermilk, the higher the fat content the better, such as whole milk for better flavor. In my bread machine, I use powdered because it won't spoil. You may have to add in additional oil to compensate. Some recipes call for adding the sugar to the yeast and liquid mixture, or others call for adding the sugar in with the dry ingredients.