I usually bring my soon to be vegetable stock to a boil and then let it simmer for about an hour. One of my favourite ingredients is dried Shiitake, which I tend to buy whole and in bulk. Should I go with the common wisdom of increasing the surface area by cutting the dried mushrooms into smaller pieces to extract the most flavour, or does it not really matter under the conditions of making the vegetable stock? Perhaps dried Shiitake, at that temperature, already gives me complete extraction from the interior, and I get to indulge in keeping them whole and pretty. 
 Are whole dried Shiitake sufficient for complete flavour extraction in my stock  Of course! Don't bother cutting them up, as that would make them prone to releasing too much of their flavor long before the stock is ready. 