When Should You Add Dressing to a Salad?

A leaf is made of cells filled with water, and it gets its crispness from this internal pressure. Salt and acid in the dressing make the environment outside the leaf more concentrated; water moves out of the cells toward the more concentrated side. As the pressure drops, the leaf relaxes and droops. This process begins within minutes; lettuce salad dressed half an hour earlier is no longer crisp. That is why the salad bowl is prepared close to serving time and is not left on the counter for long. For the same reason, once salad is plated, it should not sit for long either; serve it right away.

Oil has a separate effect. The film of oil coating a leaf makes it look glossy but also weighs it down; a salad with too much oil feels sticky on the plate. Also, the water and oil that collect at the bottom of the bowl separate, and the dressing no longer clings to the leaves. So add the dressing a little at a time; toss the leaves and check them each time, adding a little more if needed. The dressing can be made ahead and kept in a jar; there is no problem when the only thing waiting is the dressing itself.

The rule is not the same for every salad. Cabbage, carrot, celery, grain, and legume salads are already sturdy; they are better after sitting with the dressing for half an hour or even a few hours, because the flavors meld and firm textures soften. The same is true of piyaz with onions. Dressing these early is not a flaw; it is part of the recipe. Add a little more dressing to these salads because the firm ingredients absorb some of the liquid.

The way you toss also affects the result. Mix the salad in a wide bowl, not a narrow, deep one, so the dressing reaches each leaf with less movement. Do not press down with a spoon; toss from the bottom upward with your hands or two tongs. Lift the leaves without crushing them. Dry washed leaves thoroughly first; otherwise, the dressing will sit on top and run to the bottom. If you chill the bowl beforehand, the leaves will not warm up while being tossed and will stay crisp longer. You can use two spoons instead of tongs, but they need to be long enough to reach the bottom of the bowl.

For a large gathering, there is a practical approach. Prepare the salad without dressing and put it in a bowl; serve the dressing in a separate container so everyone can pour it over their own plate. That way, latecomers still get crisp salad, and leftovers stay unsoggy until the next day. For the same reason, add watery ingredients such as tomatoes and cucumbers at the very end, and do not chop and hold them separately. Undressed leftover salad will keep in a sealed container in the refrigerator for 1 more day and can be dressed again the next day. Shake separately served dressing before each use, too, because the oil and acid separate while it sits.