“To concasse” is a technique done to vegetables that requires peeling, seeding and rough chopping. “Tomato concasse” is the most common vegetable to concasse. First one must peel the tomato. To do this we cut an”x” through the tomato skin on the bottom and then drop the tomato into boiling water for 30-50 seconds, or just until the tomato is slightly cooked under the skin and the the skin starts to recede at the “x.” Remove tomato to a ice water bath to stop the cooking and then the peel will come off easily.
To seed, for concasse, we cut the tomato horizontally, (as you might slice for sandwiches), but in the middle exposing two halves of tomato cavities where the juice and seeds are. Over a bowl to catch the juice, push the seeds and juice out from each cavity of each tomato half with your fingers. Save the juice for another purpose or just drink it! At this point the tomato is all “meat,” and can be rough chopped for your recipe.
Option: If the skin is tough it is best to remove for most raw tomato applications. However if the skins are tender and young, they may be left on and be very acceptable.