Mix together in big bowl:
2 cups rolled oats
1 cup rolled barley flakes
1 cup rolled wheat flakes
1 cup rolled rye flakes
Add: 1/2 can to 1 full can thawed frozen apple juice concentrate; pour it undiluted directly over the grains to moisten. The purpose of this is to add a little sweetness. Sprinkle with 1 tbl. cinnamon over moistened grains and mix well. Spread out on cookie sheets and bake in a 350ºF oven. After about 20 minutes, take both cookie sheets out and stir everything up.
The idea is to dry out the moisture and lightly toast the grain without burning it. Keep checking it and stirring it about every 15 minutes or so until it seems to be completely dry and about the right color.
Turn down the heat to 300ºF after about 45 minutes so things will continue to dry out without getting too dark. When it seems to be done, take the cookie sheets out and set them on the counter and leave them to cool off completely.
When completely cool, dump the mix back into a big bowl and add about a cup or so of raisins; mix well, then put it in a big jar. The important thing is to make sure that it’s completely dry. If not,it will mildew just like a loaf of bread.