Both silken and regular tofu can be found in soft, medium, firm and extra firm consistencies. They are made from the same ingredients, but they are processed slightly differently, and are not interchangeable in a recipe.
Most recipes will let you know when silken tofu is needed. I find that there is little difference between firm and extra firm silken tofu, and for most purposes, the different kinds of silken tofu are interchangeable, so don’t worry if your grocer only stocks one kind.
Salad dressings, sauces and desserts usually use silken tofu for a thick and creamy texture. Silken tofu in an aseptic container has a shelf life of up to a year, unopened. Once opened, submerge any used portion with water in a container, cover, and refrigerate for up to a week.
Silken tofu crumbles very easily. It is not recommended that you press silken tofu; only regular or firm tofu needs to be pressed. Use a gentle hand when carefully slicing silken tofu, as it may otherwise fall apart.
Regular tofu, also called Chinese-style tofu or bean curd is more common than silken tofu and comes in a plastic container in the refrigerator or produce section of most grocery stores. Firm or extra firm regular tofu is best used in stir fries, tofu bakes or any dish where you will want the tofu to retain its shape. For recipes that call for crumbled or mashed tofu, such as mock ricotta or scrambled tofu, firm tofu will work just fine, though medium or soft tofu will have a smoother consistency.
To learn more about tofu, see also:Nutritional Value of Tofu
How to Press Tofu