Freshness, color, and shape are the points generally considered in buying mushroom. The best quality mushrooms are clean, fresh in appearance, white, creamy white or tan, free from open caps, pitting, discoloration, wilting, or injury.  Sizes should range from3/4 inch to3 inches in diameter.  If the caps are open, the gills should be light in color. Avoid mushrooms that are withered or have open veils around the base of the cap, as these are signs of old age. Gills that are brown or black indicate over age mushrooms and should be avoided.  The size of the mushroom is not a reliable indicator of tenderness.