What is the short blessing after food that Abraham taught?
Here is the translation of the prayer that Abraham taught his Gentile guests to say after they ate food to their satisfaction, in order to teach them that there is only One True G-d (from the Midrash on the Book of Genesis):
“Blessed is G-d of the Universe, from Whose bounty we have eaten.”*
As taught by Rabbi J. Immanuel Schochet o.b.m. and Rabbi Moshe Weiner of Jerusalem, Noahide individuals and families are also encouraged to recite thanks to G-d before eating a meal or a snack. Those short words of thanks can mention the type of food or drink that one is about to partake of. For example, one can recite thanks and blessing to G-d for:
1) “bread from the earth” (for any bread that is made from grain flour – wheat, barley, rye, oats or spelt – with water as the main liquid)
2) “fruit of the tree” (for fruits that grow on perennial trees, bushes and vines)
3) “fruit of the earth” (for edible roots, leafy greens, all vegetables, legumes, and fruits that don’t grow on trees)
4) “fruit of the vine” (for grape wine and grape juice)
5) “sustaining food” (for non-bread foods made from grain flour, such as crackers, pastas, pastries, etc.)
6) “all that is created by His word” (other foods that don’t grow from plants with roots in the ground, such as: meat, beverages, candy, milk, eggs, cheese, mushrooms, etc.)
#3 can also include #2
#6 can also include all the others.
A prayer of thanks to G-d for bread at the start of the meal (#1) includes within it everything else that will be eaten within the meal (since bread, which is the “staff of life,” is the most important food), so no mention of thanks for the other foods or beverages within that meal is needed – except for grape wine or grape juice, which has the most important status among beverages.
Likewise, a prayer of thanks to G-d for drinking grape wine or grape juice (#4) at the start of a snack or a meal includes all the other beverages that will be drunk within that occasion. So in that case, a separate blessing upon drinking any other beverages afterwards is not needed (even if bread in not being eaten).
*From Midrash Rabbah ( Genesis), ch. 54.