A blessing on food or drink must be recited before consuming even a small quantity (168:9;210:1), and even if the food has been broken into small pieces (205:4). A blessing need not be recited after eating less than a KE-ZAYIS or drinking less than the volume of 1.5 eggs; but according to some, it is recited after eating an entire object such as a grain or drinking a KE-ZAYIS of wine (210:1). If a food or drink contains several ingredients, only the blessing for the primary ingredient (168:8;202:4; 203:7;204:11-12;212:1-2) or the majority ingredient (208:7) is recited before or after it (212:1). The ingredient that gives the mixture its flavor is usually regarded as primary, provided it is substantive and not just a flavoring such as a spice, and especially if it is grain (see 204:12); but an ingredient that is used to give the mixture color or odor, or to bind or thicken it, is not regarded as primary (204:12;208:2-3,9). A liquid mixture is treated like its majority ingredient (202:1) or its strong ingredient (see 204:5-6).
No blessing is recited on food or drink that is not normally suitable for consumption (202:2-5;204:2,4) by itself (see 202:16) unless it is made suitable (see 202:3). No blessing is recited on something that is taken only for medicinal purposes (204:7); but if it is tasty, even if it is forbidden (204:9), a blessing is required (see 204:8,11). No blessing is recited by a person who is forced to consume something (204:8). If a person eats or drinks something and forgets to recite a blessing, he does not recite it afterward (see 172:1); if he has not yet swallowed it, he may keep it in his mouth (or take it out, if this would not spoil it) and recite the blessing (172:2). A person who tastes food does not have to recite a blessing unless he swallows a significant amount of it (210:2).
There should be no significant delay between reciting a blessing and beginning to eat or drink (206:3). The thing on which the blessing is being recited should be held in the right hand (206:4). If that thing is accidentally lost or spoiled, another thing of the same kind may be taken, provided the blessing was intended to be valid for it too (206:6). A blessing is valid even for things of the same kind that were not present when it was recited, unless they are unexpected (206:5-6). If a person is uncertain whether he has recited a blessing on food, he need not repeat it; and similarly for blessings after food, except for grace (209:3).
When two or more people are sitting together, one of them may recite the blessings before and after bread or wine (see 174:8) for all of them, provided they listen to the blessings with the intent of fulfilling their obligations; but this must not be done for other foods or drinks (213:1-3).
A blessing must be recited before smelling a pleasant fragrance, but no blessing is recited afterward (216:1). The general blessing on fragrances is “…Who creates types of fragrances”; this blessing is recited on mixtures of fragrances of different types (217:1) or in cases of doubt as to which blessing is required. There are special blessings if the source of the fragrance is wood or a plant stem; a grass or flower; an edible plant substance such as fruit, provided it has a natural fragrance (see 216:5) and the intent is to smell it, not just to eat it (216:2); or an oil (216:4). For examples of these types of fragrances see 216:2-9,14; on precedence see 216:10-11. When incense is burned to produce a fragrance, the blessing should not be recited until it begins to smoke (216:12-13). No blessing is recited on a fragrance whose source is no longer present even if it can still be detected (216:6;217:3), or on a fragrance that was produced only to counteract a bad odor (see 217:2-3), or on a fragrance that comes from a forbidden source (see 217:4-7), or on a mixture of fragrances in which such components are in the majority (217:6).
Shulchan Aruch, Copyright (c) 2000 Project Genesis, Inc.