Use this stock to make soups, sauces, and risottos. To shave kernels, cut off tip of cob and stand the ear in a wide bowl to catch the kernels. Then with a very sharp knife, slice downward.
Place vegetables in large pot; add 10 cups water, parsley, thyme, and peppercorns.
Simmer, uncovered, 20 minutes; strain liquid; discard solids. Use immediately or freeze in airtight containers up to 3 months.