Halakha Mazmur 86:6: Mishneh Torah, Blessings

It is also an ordinance of the Sages that before partaking of any food, a blessing is first recited and then it is eaten. And however little one intends to eat or drink, the blessing is first recited and then the refreshment is taken. So too, one who wishes to smell a fragrant odor first recites the blessing and then enjoys the fragrance. Whoever partakes of any enjoyment without reciting a blessing commits a trespass. It is also an ordinance of the sages that a blessing is to be recited after eating or drinking, provided that the quantity drunk is at least a quarter of a log (equal to the volume of an egg and a half), and the food eaten is at least as much as an olive in size. A cook who is tasting food does not need to recite a blessing before or after doing so, provided that the quantity tasted is less than a quarter of a log.