Place wheatberries in a strainer and rinse under cold water. In a large pot, combine wheatberries with 2 1/2 quarts salted water, and cook until al dente, about 50 minutes. Drain, and set aside.
Heat olive oil in a medium saute pan over medium heat. Add onions, and cook until translucent, about 3 minutes. Stir in mushrooms, and add white wine. Simmer until wine has evaporated, about 7 minutes. Add onions and mushrooms to wheatberries in a medium bowl. Toss with parsley and sage, and season with salt and pepper to taste; serve warm.