The Gemara in Masechet Berachot (35a) tells us that if one enjoys anything in this world without having first recited a blessing and thanking Hashem for the item one is enjoying, this is tantamount putting items consecrated to the Bet Hamikdash to personal use. This means to say that one who eats without reciting a blessing transgresses a prohibition of which the severity is similar to have desecrated the sanctity of consecrated items, for the entire world belongs to Hashem.
Desecration of Consecrated Items Not Applicable to Pleasant Smells
The Baraita (a Mishnah related by the Tannaim, however, not recorded in the Order of the Mishnah and is quoted by the Gemara) in Masechet Pesachim (26a) states: “One does not transgress the prohibition of using consecrated items for personal use when it comes to voice, appearance, and smell.” This means that if one smells the incense that was burned in the Bet Hamikdash (in the forbidden manner explained in the Gemara ibid.), although one has sinned, one is not punished in the same manner as one who uses a consecrated item for personal use, for smelling, hearing, and seeing are not considered tangible enough enjoyments to become liable for transgressing this prohibition.
We can seemingly imply from here that one who enjoys a pleasant smell without reciting a blessing should not be considered as if he has used a consecrated item for personal use, for as we have established, the enjoyment of smell is not included in this prohibition. For the same reason, it seems that one should not be obligated to recite a blessing on the enjoyment of smell.
“Let Anything With a Soul Praise Hashem”
The Gemara in Masechet Berachot (43b) indeed questions why one must recite a blessing for the enjoyment of a pleasant smell to which Rav answered that this is derived from the verse in Tehillim (Chapter 150), “Let anything with a soul praise G-d, praise Hashem.” What is it that the soul enjoys and not the body? This must refer to smell. This means that the enjoyment of smell is not quite as physical as eating and the enjoyment is primarily spiritual in that the soul enjoys the pleasant smell. Thus, we learn from this verse that one must recite a blessing on the enjoyment of pleasant smells.
Which Blessing is Recited on a Fragrant Object?
If the smell emanates from a type of tree (such as cloves), one recites the blessing, “Baruch Ata Hashem Elokeinu Melech Ha’Olam Boreh Atzeh Besamim.” If the smell emanates from a type of plant (such as mint leaves), one recites the blessing, “Boreh Isbeh Besamim.” If one smells a fragrant fruit of a tree (such as an Etrog) one recites, “Ha’Noten Re’ach Tov Ba’Perot.”
One should preferably recite the appropriate blessing for each kind of pleasant smelling object, either, “Atzeh Besamim,” “Isbeh Besamim,” or “Ha’Noten Re’ah Tov Ba’Perot.” However, if one recites the blessing, “Baruch Ata Hashem Elokeinu Melech Ha’Olam Boreh Minei Besamim” on any type of fragrant object, one indeed fulfills one’s obligation, for all pleasant-smelling items are included in this blessing.
Thus, for certain fragrant objects whose blessing is doubtful, one should recite the “Boreh Minei Besamim” blessing, as we have explained (Shulchan Aruch, Chapter 216).
For this reason, on fragrant objects about which we are uncertain which blessing to recite, the “Boreh Minei Besamim” blessing is recited, as we shall explain (Shulchan Aruch Chapter 216).