The Lutheran Church is one of several denominations that teach the Real Presence, but they don't all understand it the same way. The Lutheran understanding differs significantly from the Orthodox and Catholic positions; could someone explain the Lutheran understanding of this doctrine?
This is a hard and subtle question. I am here to tell you, this topic does not preach. If you wanna preach on this, get your hospitality krewe to serve coffee BEFORE your service, not after.
What DOES preach is the surpassing mystery of Holy Communion. What DOES preach is the idea that we get the same thing those folks got that Thursday night long ago in the night in which Jesus was betrayed. What DOES preach is the overwhelming spiritual power of those scraps of bread and drops of wine.
What DOES preach is the idea that we are seated all together at one great table, enjoying one great feast, with the whole church through the ages and around the world. We share that table with Peter, who would go on to deny Jesus. We share it with Judas, who would go on to rat Jesus out to the cops. We share it with the disciple whom Jesus loved, who would comfort his mother at the foot of the cross. And, at the head of the table is Jesus, the one who gave of himself so we might have life. Yes, he is present at the table. He is present in the meal.
Who cares what preaches? Because the Lutheran understanding of the sacrament of Holy Communion is this: Jesus Christ instituted it to give strength and comfort to us human beings (Peter, Judas, you, me) by nourishing our faith and feeding our souls.
Here's a little history and doctrine. I'm digging this out of my notes from Uncle Tim Wengert's class at the Lutheran Theological Seminary at Philadelphia.
The Lutheran Book of Concord is the authoritative source for the doctrine of our strain of Christianity on this subject. The important historical thing to keep in mind is that the 16th-century reformers who forged those documents (first among them the Augsburg Confession) were caught in a squeeze between two groups.
One of the jaws of that vise was the late-medieval Roman church, and their claim of the time that the Mass was a sacrifice, and that consuming the bread "worked" on people ex opere operato, that is, as if by magic just by doing it, without any need to touch their consciences.
The other jaw was the Zwinglians of Zürich and their claim that the Lord's Supper is a memorial and a remembrance of Christ. (The Calvinists of Geneva weren't a factor at the time these documents were forged).
The "in, with, and under" theology of Jesus Christ's presence in the bread and wine is, practically, the way Martin Luther, Philipp Melanchthon, and their colleagues dealt with the vise. The path they chose is effectively a middle way (even though they strenuously claimed it was the only faithful way).
OK, you can wake up now. Enough church history.
Why do Lutherans believe and teach that Jesus Christ is present in the bread and wine?
Why is the "in, with, and under" theology different from the Roman theology?
The Augsburg Confession says, "the true body and blood of Christ are truly present under the gestalt of bread and wine in the Lord’s Supper and are distributed and received there." The Apology of the AC says "Christ commands that it be done in memory of him. The Mass, therefore, was instituted so that the faith of those who use the sacrament should recall what benefits are received through Christ and should encourage and console the anxious conscience."
Another thing Luther said is that we need to take our rational selves prisoner in the face of mysteries like this, and simply allow the mysteries to be part of our lives. So, to sum up my answer, "I don't know."
To get this, we have to start with the definition of transsubstantiation.
The idea of "transubstantiation" is that the bread and wine at the time of communion (after it has been blessed/consecrated) actually becomes the blood of Jesus and body of Jesus (physical blood and body of Jesus, not just symbolic) .
If you compare this with the Lutheran concept, it's kind of the reverse. The idea here is that the bread and wine become joined with the body and blood of Christ.
Think of it this way: If you have a piece of clay and you take a bit of mud and add it to the clay, the mud becomes part of the clay. This is the idea of Real Presence. The idea of transubstantiation is that the mud turns into clay and is therefore joined to the clay--as opposed to the mud joining with the clay in order to become part of the clay.
Edit the theological term for this is "Sacramental Unity". Wikipedia lists all the different doctrines regarding communion.