Halacha: What Blessings to Recite on Wafers?

On wafers, recite Mezonot (first blessing)

After eating, recite Al Hamichya (last blessing)

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The amount required for a last blessing (from "Daily Halacha" by the decisions of Maran Rabbi Ovadia Yosef ztz"l):

For anything a person eats, they must recite a "first blessing" on it, such as "Shehakol" or "Ha'etz." Even if they eat only a small amount, they are obligated to bless it, as long as they eat it with the intent of consumption. (However, if they only taste it to rectify it by adding spices, they do not bless that consumption at all). Therefore, someone who chews flavored gum, even if they swallow only a tiny amount, must still bless for enjoying the taste of the gum. Similarly, if one drinks something, they need to bless it even if they only sip a small drop of that beverage.

However, this applies specifically to the first blessing, but a "last blessing" is only recited when a person eats an "important consumption," which is the size of "kazayit," meaning twenty-seven grams, and in drinking, the measure is "revi'it," which is eighty-one grams.

Additionally, the eating or drinking must occur within a time frame such that the eating or drinking combines. If one were to consume over an entire day the size of a "kazayit" of bread, crumb by crumb, they surely cannot recite the Grace after Meals. The "kazayit" consumption must occur within the duration of "Achilat Pras," and there is a dispute among the poskim about this duration. Some say it is five minutes, others say seven and a half minutes, and there are other opinions. Therefore, it is prudent always to consume a "kazayit" (particularly during Shabbat meals) within four and a half minutes to fulfill all opinions.

Regarding the last blessing on a beverage, one must drink a revi'it (eighty-one grams) all at once, as pausing between sips negates the obligation to recite a last blessing. Therefore, someone who drinks soup with a spoon does not bless after consuming the soup, as they did not drink a revi'it all at once. Similarly, one does not bless after drinking hot coffee or tea, as it cannot be consumed all at once.