I would want to very carefully vet any comments that any Catholic parish is using anything except wine and unleavened bread for the Eucharistic substances. And I do mean very carefully.
The Church has held from its beginning that Christ gave the power to bind and loose, and that has been interpreted to include authority over what is or is not valid for the celebration of a sacrament.
The Roman rite uses unleavened bread; interestingly, at least some of the Eastern rites use leavened bread. Both are accepted within their own rites (that is, a Roman Catholic priest celebrating the Roman rite, either what is knows as the Ordinary Form or the Extraordinary form of the Mass, must use unleavened bread.
The hosts which are generally used can vary in thickness and in color (for example, some are relatively white; some a light tan), but are made only of wheat and water.
Wheat was the grain used by the Jews; and the celebration of the Passover required that it be unleavened. The first Mass was during the Passover meal, which we refer to as the Last Supper. And wine was common in Jewish celebrations, and used at the Passover meal.
As those were the elements Christ used, the Church has done likewise; and based on the “bind and loose”, exercise the authority to limit the elements to those items.
I attend Mass occasionally at our local Trappist abbey; they consecrate a large, tan host which is somewhere between 1/4 and 1/2 inch thick and scored so that it is easily divided into pieces which are about 1" or less in diameter. As they are a small congregation and do not have many people attending Mass most of the time, an individual on a weekday might receive part of that host; on weekends they make the smaller wafers available and most visitors receive that. The large host is only weat and water, but due to issues of crumbs, not widely used.
Because of the history of the Eucharist going back to the Last Supper (and thus to the Jewish celebration of the Passover), the history and practice has been to do what Christ did, and use what Christ used. And so the Church holds that other substances do not comply.
As a note, water is used for baptism; so another substance (such as the proverbial soft drink, as the only thing available in an emergency) does not suffice and cannot be used.
And if used, neither grapefruit juice nor Coke would make for a legitimate sacrament.
I suspect you are dealing with Protestants on the issue. The Bible is not the sole source of theology or information; and sola scriptura is nowhere stated in the Bible; that is a rejection of the Catholic Church and a strike out at what the Church terms Tradition (as opposed to tradition). It is likely you will not convince them of the legitimacy of what the Church practices; because they will only accept as authority what is in the Bible (and then they will dispute what constitutes “the Bible”). Further, the Church managed to go for 1,200 + years before someone came up with “sola scriptura”. Amazing that it did not start oh, say about 1,100 years earlier.