Hey Spark, have you ever come across info that eludes to Walnut syrup being problematic to some people. My thought is that the Tannins in the wood might be in the syrup too. Some folks are kind of "allergic" to walnut dust and such.
We recognize the possibility, and take great pains to try and separate the walnut from the maple. Separate storage tanks for the sap, dedicated filters, etc. We do boil in the same stainless pans, but they are cleaned thoroughly in between batches.
Nevertheless, we tell everyone who wants maple syrup that it was processed in a facility that also processed walnut syrup, and with it being a tree nut....better safe than sorry.
I don't know about the tannins, but the walnut contains a pectin that makes filtering a huge pain. We're getting there with it, one more reduction and filtering and we will bottle in 1.7 oz bottles. Just enough for folks to get a taste of the stuff.
