It is important to know the matter of the Holy Eucharist. It is the Bread and Wine that are brought for consecration. There are rules and guidelines with regard to the kind of bread and wine to be used in the celebration of the Holy Eucharist. (based on Redemptionis Sacramentum 48-50)

The Bread

1. The bread must be unleavened, purely of wheat, and recently made so that there is no danger of decomposition. 

2. The bread should be from wheat without any mixture of other substance. A bread, though it may be wheat bread but because of some substance mixed can never be used for the Holy Eucharist. If it is mixed with another substance different from wheat to such an extent that it would not commonly be considered wheat bread, does not constitute valid matter for confecting the Sacrifice and the Eucharistic Sacrament.

3. It is a grave abuse to introduce other substances, such as fruit or sugar or honey, into the bread for confecting the Eucharist.  

4.  Hosts should obviously be made by those who are not only distinguished by their integrity, but also skilled in making them and furnished with suitable tools. 

The Wine

1.  The wine that is used in the most sacred celebration of the Eucharistic Sacrifice must be natural, from the fruit of the grape, pure and incorrupt, not mixed with other substances. 

2. During the celebration itself, a small quantity of water is to be mixed with it. 

3. Great care should be taken so that the wine intended for the celebration of the Eucharist is well conserved and has not soured. 

4. It is altogether forbidden to use wine of doubtful authenticity or provenance, for the Church requires certainty regarding the conditions necessary for the validity of the sacraments. 

5. Nor are other drinks of any kind to be admitted for any reason, as they do not constitute valid matter.