QUESTION

May one roll sushi on Shabbat? May one chop vegetables for sushi?

ANSWER

Why should chopping vegetables be a problem? Tochein? It’s fine if you plan to eat it right away – see Shulchan Arukh OC 321:12,

המחתך הירק דק דק, חייב משום טוחן… וכל זה לא מיירי אלא בחותך ומניח, אבל אם לאכלו מיד, הכל שרי מידי דהוי אבורר לאכול מיד, דשרי

Regarding the roll, I have to tell you that in the past I had doubts that it might be forbidden. Some people feel strongly that it is no different than a sandwich or making any concoction without cooking in the kitchen, but I wondered if it is a type of boneh (which exists by food, see making cheese) – putting together disparate pieces to make a whole, and this is actually a new creation much more than a sandwich or salad (IMHO), all held together tightly.

HOWEVER – I reversed myself. The Gemara says that אין בנין בכלים and that should definitely apply to food. Now, אין בנין בכלים does not mean that it is not a problem to make a keli from scratch, just that it is not boneh to put the pieces back together. As Ramban says – there isn’t boneh bekeilim, but there is boneh keli. So – the only time the Gemara applies boneh to food is cheese – making it from scratch, like making a keli from scratch. But just as it is not boneh to put the pieces of the keli together, it is not boneh to put the pieces of the sushi together. This is the overwhelming consensus, but Kitzur Shulchan Arukh 80:25, says the strict approach that I had initially considered,

איסור ‘בונה’ שייך גם במאכל, כגון המגבן גבינה, או שמדבק פירות ומשווה אותן שיהיו יפין ולכן כשחותכין בצלים עם ביצים, או עם ‘חלב’ מדג מלוח, יש ליזהר שלא להשוותן ולייפותן, אלא יניחם כמות שהם