Divide 86 by your sap's sugar content percentage to get the ratio. At 2% sugar: 86 ÷ 2 = 43 litres of sap per litre of syrup. At 2.5% sugar: 86 ÷ 2.5 = 34.4 litres. Finished maple syrup is 66° Brix (66% sugar). A refractometer or hydrometer is the best way to measure your sap's sugar content.