To the questioner,

Substantial eating:

One who ate bread until satisfied should recite lchatchila within 72 minutes of finishing the meal; and bediavad, if 72 minutes have passed, as long as he is not hungry again because of that same eating, he may recite Birkat Hamazon.

And if 72 minutes passed and he is uncertain whether he is hungry or not, if he ate to satiety such that his obligation to recite Birkat Hamazon is מן התורה, he may recite it (and in such a case it is better that he eat a kezayit of bread before Birkat Hamazon).

These laws are also true of one who ate other foods and not bread [but in a case of doubt he does not recite the blessing, since the obligation to bless is only rabbinic].

Light eating:

If he ate a small amount and was not satisfied, lchatchila he should recite the after-blessing immediately, since it is not clear what the measure of digestion is in such a case. Therefore, up to half an hour he may recite it without problem.. And bediavad he may recite it up to 72 minutes.

Drinking:

According to the Shulchan Aruch, one who drinks a significant amount of a beverage (up to the point of satiety) may recite an after-blessing as long as he does not feel thirsty. But if he already feels thirsty again, he may not recite an after-blessing for what he drank.

In a case where he does not know how to assess whether he is indeed thirsty again or not - up to half an hour he may recite an after-blessing; and if half an hour has already passed, he should hear the blessing from someone else, or drink another cup of a beverage, or eat something else whose blessing is borei nefashot, and thereby exempt the beverage he drank at the beginning.

(Taken from the website https://shaalvim.co.il/torah/view.asp?id=15)

With blessings,

The Hidabroot team