Remove cores and stems from the crab apples. Fill a pot about 3/4 full of crab apples and cover with water. Boil them down whole for about an hour and a half, or until the apples are a thick slurry. Strain the slury through an old clean white t-shirt. What is left in the t-shirt is crab apple sauce. The syrup is the liquid portion strained through. To test for pectin content in the syrup, drop a spoon full of syrup into a clear glass about half full of rubbing alcohol. If it turns into a clear gell after a few minutes, then you have pectin, if not, you can boil it down and strain further until it passes the test. Mix crab apple syrup & maple syrup together in a 3 to 1 mixture for a sweet/tart combination. Use the same ratio for the crab apple sauce. The pectin can be used for making jelly and jam.