We made some Black Walnut syrup last year, I think there's a little info in this thread, matter-of-fact.
Be warned, it takes about 90 gallons of sap to make a gal. of syrup, and the walnuts are pretty stingy with it....You might look into some type of cold storage for the sap, until you accumulate enough for a boil. We filled plastic freezer containers with sap, froze em', and used them as giant ice cubes in the storage tank. Worked pretty well.
Filtering is another hassle. As it reduces it creates a pectin, which plugs the filters right NOW. Have extras standing by, especially pre-filters.
It's a pretty syrup, fairly dark, very sweet, with a distinctive taste. We had planned to try and produce more this season, but circumstances overcame us and we shelved syrup production this year.
One more thing....unsure of what you plan on doing with the walnut syrup, but info is hard to come by. There is a school of thought that considers the possibility of nut allergen with walnut products. We kept all our walnut separate throughput the entire process, and were careful to notify all who wanted to try it that it was processed from a nut tree. Just a thought.
