Nedarim 53: When Foods Spill Into Each Other... Figuratively

Our first Mishna refers to specific food by-products, like date honey from dates or vinegar from late dates.  Our rabbis debate whether or not these by-products are included in vows forbidding a person from eating the primary food described in the vow.   Our next Mishna questions the inclusion of sweet apple wine when wine is stated, sesame oil when oil is stated, leeks when kaflutot  (a cabbage dish) is stated, and wild field vegetables when vegetables are stated.  It notes that at times a modifier is used to further describe vegetables and other items.

The Gemara looks at what is usually said in specific places.  For example, in a place where olive oil is the primary oil used, then sesame oil is permitted when one takes a vow forbidding oneself consumption of nonsepcified oil.  If both olive and sesame oils are used in that place, sesame oil is included in that same vow.  And if sesame oil is the primary oil used in that place, then olive oil is not included in one's vow.

As well, the Gemara considers vows made at unusual times, including shemita, the sabbatical year.  Because the rules are different that year, assumptions are different, too.  If a person vows not to eat vegetables, for example, then normally that refers to garden vegetables but not field vegetables.  The reverse is true during shemita, for garden vegetables cannot be used during the shemita year, and so field vegetables are assumed to be the main source of vegetable consumption.  The Gemara also wonders about whether our Mishna might be referring to differences that apply within and outside of Eretz Yisrael.

A final Mishna questions what is included when one vows to not to eat foods that are included in commonly eaten foods - pounded beans or garlic in stew, for example.  Although they argue about guidelines, the rabbis lean toward including ingredients that add substantively to the flavour of the dish.  Similarly, if the dish can be made without that ingredient, then the person who has vowed not to eat that ingredient is permitted to eat the full dish.  

Regarding permitting the use of foods in unusual ways, the Gemara suggests that chewing on raw beans should be allowed even if one has vowed not to eat beans.  This is because chewing on raw beans is so unusual that it would not have been an intended part of the vow.