Does the type of flour used [for unleavened bread] such as white or wheat matter? If so where in the Bible do I find it?
Thanks for the question.
The type of flour is dependant on what tastes good to you, or in Bible times what was available.
In the scriptures you see them have wheat or barley. Remember "five barley loaves and two fish"? And the ears of grain that the Lord and the disciples picked and rubbed in their hands were wheat spears.
Of course most Americans like white flour, which is really wheat.
There were also 3 grades of flour.
1. Course or beaten.
2. Bruised or crushed (ground in a mortar)
3. Fine (milled and sifted for honored guests)
Our brown or "wheat" flour is actually the whole grain with the kernel and the bran, which makes it brown. Our "white" flour is actually wheat also but has been refined, i.e. stripped of the bran and bleached.
What I have always seen churches do for the Lord's supper is just buy Matzos at the local store and use that. It is unleavened wheat bread produced for Jewish feasts that call for unleavened bread.
While getting the ingredients right is fine, remember that during the Lord's supper one should forget entirely what the bread is made of and focus instead on the body of the Lord and his love for us.