When someone says wine, most people will think of grapes, or getting drunk. But with mitzvot everything has to be specific because sometimes if it’s not the mitzvah won’t be fulfilled. So obviously, many commentators want to delve into this topic and try to answer the question, what is considered wine? In a Tosefta (material that wasn’t part of the Mishnah) about giving wine to the poor that Rav Yehuda comments on, he says “It should at least have the taste and color of wine.” We take that to mean that the rabbi believes that you don’t need crushed grapes to fulfill the mitzvah, making it more accessible to the poor. There is another question many parshanim have focused on, What is considered a cup. Not the physical object you put liquid in, the measurement. The reason this is an issue is because back in the time of the Talmud, practically no one would drink pure wine, it was almost always diluted by water. Rav Yehuda quotes Shmuel saying:
אַרְבָּעָה כּוֹסוֹת הַלָּלוּ צָרִיךְ שֶׁיְּהֵא בָּהֶן כְּדֵי מְזִיגַת כּוֹס יָפֶה
Or in English “These four cups must contain enough undiluted wine to allow for diluting a significant cup.” This means that in the four cups you drink at the Seder as a mitzvah, you must have at least enough pure wine in the diluted cups to fill a single glass in order to complete the job. Rabbis all over the world debate many weird topics like this one, they will almost certainly never reach a decision on these matters, but we can in our own homes. It is our duty to fulfill the mitzvot set to us by our religion, so we must decide ourselves how to make them work. Everyone should be able to participate in these religious duties, and that’s why so many rabbis try to find a way for people with less resources to complete them. We should all strive as Jews to find a way to include everyone in our religion and to make sure everyone can do as they wish.