There is a resent picture on this forum of another who tried this with material from a fabric store. His syrup was blue in the end. Not sure I would experiment with it just easier to purchase the food grade.
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2014 - Pots, Pans, and Chaffing dishes on 3 burners, 10 trees with 20 taps - 120 g sap produced 3 gallons syrup
2015 - custom pan and warmer on 2 - 212k propane burners, 17 trees with 40 taps - 150 g sap to date syrup production in process
2016 - desired 10 gallons finished product, need more better storage!