Wasabi Paste is a special ready-to-use paste, green colored, produced from stems of wasabi, a plant, member of the Brassicaceae family (which includes mustard, cabbage and horseradish), also called Japanese horseradish.
This paste is traditionally used in Eastern cuisine, especially in Japan. Wasabi has an extremely strong flavor, more similar to a hot mustard than a chili pepper. Its special hotness is mainly felt in the nose and the higher part of the throat, more than on the tongue.
On the market you can find Wasabi either as a stem, which must be very grated before use, as dried powder, or as this paste in tubes. Since it quite expensive, you can find several imitations, but the real most common varieties are wasabi mazuma, with a lighter color and hotter taste, and wasabi daruma, di colore verde intenso. Wasabi is generally sold either as a stem, which must be very finely grated before use, as dried powder in large quantities, or as a ready-to-use paste in tubes
They say Wasabi has a digestive and antibacterical function, that’s why it is usually eaten together with raw fish, like in sashimi. You can also use it to season salads and vegetables, or meat dishes, or even to make snacks. In restaurant Wasabi Paste is usually served in a small bowl, apart from the other ingredients of the dish.
Fun fact: Since it mostly grows submerged along stream beds, the part of the plant used in the kitchen as a condiment is usually referred to as a root or rhizome, but it actually is a stem.