Bento in Japan can range from something as simple as white rice with a single umeboshi in the center to extravagant special occasion meals. Bento cooking is very different from everyday cooking in many ways.
Entire books are written on the subject of professional bento cookery - this is a summary introduction to our approach to cooking bento at Hayato.
A typical bento is similar to a teishoku, it consists of a primary dish, some side dishes, rice and pickles, all served as a set. Because Hayato is a kaiseki restaurant and our job is to create elaborate multi-course meals, we need to make a bento that is very different than what a home cook would make.
Rather than thinking of components as side dishes to accompany rice, or okazu, we need to make dishes that would be good enough to be individual courses in a multi-course meal. We also need to choose items that complement and contrast each other just as they would in a multi-course meal. In Japanese cuisine this is primarily accomplished by using different cooking techniques: grilling, frying, steaming and simmering. Different techniques used on contrasting ingredients should produce enough variety to entertain the diner throughout the course of the meal, whether it’s in the restaurant or in the bento.
Unfortunately serving the meal in a takeout box presents special challenges that make bento cooking extremely difficult to do well.
The primary difficulty is that even if the bento is assembled hot, the food may fall to room temperature by the time it is eaten, and in some cases, it may sit in the box for hours. We lose the ability to alternate hot and cold dishes, which is a very important technique in Japanese cuisine. Additionally, when selecting items for a bento, we have to choose things that do not severely degrade as they cool. Foods that have more fat and sugar tend to work best in bento. Consider an American picnic basket - For picnics, we choose things like potato salad, fried chicken and strawberry shortcake. Creating bento involves a similar approach. Fried foods can be the highlight of a bento, but tempura
batter and panko are terrible when cold, so su-age (frying with no batter) works better. We choose fish like black cod because the fat protects it from becoming tough and dry when it cools. Sweet potatoes stay moist when simmered and their sweetness stimulates the palate even when they are cold. Our palates really respond to the seasoning in lukewarm foods, so bento cooking involves stronger seasoning and more sugar than kaiseki cooking. We use slightly more soy sauce, salt and sugar in bento items than we would when serving the same items in the restaurant, primarily because once everything cools the seasoning has to carry the ingredients more.
The other big hinderance in serving the meal in a box is that we cannot control the order guests eat things in.
In our tasting menus at dinner, there is a progression of increasing seasoning and richness that peaks at the end of the meal. In the bento, if one thing were extremely lightly seasoned it would taste bland if you ate it after something rich such as black cod or duck. For that reason, the average level of seasoning in bento has to be higher than it does at dinner, and the strength of each item has to be more closely matched. It doesn’t have to match exactly, but it has to be closer than it does at the beginning and end of a kaiseki meal. We don’t
necessarily need to use more sugar, fat or salt in everything, but the overall strength of flavor in an item must always be considered in relation to the other items. For lighter vegetables like winter melon that are primarily flavored by dashi, the amount of umami in the dashi has to be higher than at dinner in order to keep vegetables from tasting weak. For that reason when we make dashi for bento we use more kombu and simmer much longer than we do for our dashi at dinner.
Because seasoning takes a more prominent role in a bento, we take advantage and use more types of seasoning in order to make up for the other limitations we have to deal with. In bento the identity of each component is more defined by its seasoning.
One item will be defined by dark soy sauce, another by light soy, one with vinegar, one with sugar, one with salt, one with just dashi, etc.. By using sharply defined seasoning techniques we can try to create higher contrast in flavors between components. Those flavor contrasts are combined with textural contrast and color contrast, with the end goal of keeping the diner entertained from the time they open the lid until they finish the last bite.