What Is the Difference Between White Mushrooms and Portobello?

White (button) mushrooms and portobello are, surprisingly, the same species (Agaricus bisporus) at different maturity stages; the white mushroom is this species' young, unopened form, brown cremini is a middle stage, and portobello is the same mushroom fully mature, with its cap widely opened. So three different names actually describe three age stages of a single mushroom. How does maturity change the texture?As a mushroom matures, its cap opens, its gills darken and its cell structure loosens; that looser structure gives portobello a far meatier, spongier texture than white mushrooms. White mushrooms, still tight and compact, release less water when cooked and hold their shape better. Why is the flavor difference so pronounced?The maturing process concentrates the mushroom's umami compounds, particularly glutamate, which is why portobello carries a far more intense, "meaty" flavor than white mushrooms. That trait makes portobello a popular meat substitute in vegetarian burgers; its large, flat cap also happens to suit grilling whole. Portobello generally costs more than white mushrooms, since it needs longer to mature and is produced in smaller volumes. Cremini sits between the two on both price and flavor — richer-tasting than white mushrooms, but more affordable than portobello. The three stages also suit different cooking methods: white mushrooms work well thinly sliced and sautéed, or raw in a salad; brown cremini is used similarly but needs slightly less cooking time. Portobello's large, meaty cap makes it well suited to grilling whole, slicing and roasting, or stuffing and baking. Storage also shifts a little with maturity: white mushrooms generally keep a bit longer thanks to their tighter cell structure, while portobello's open cap makes it lose moisture and spoil somewhat faster, which is why it's best eaten within a few days of purchase. Gill color is also a practical way to spot maturity: white mushroom gills are a pale pink, while portobello's are a dark brown-black. When making a recipe that calls for a light-colored sauce or soup, white mushrooms are the better choice, since portobello's dark gills can tint the dish gray. Scraping out the gills under the cap is also a step specific to portobello; because those gills can release a lot of water when cooked, they're often scraped out with a spoon, especially before stuffing and baking. White mushrooms and cremini are rarely large enough for this step to matter, and their small caps don't run into the same noticeable water-release problem that portobello does.