my first boil was 55 gallons and and yielded 154 oz's of syrup.Saturday I boiled what sap that I could collect that was not frozen and had 25 gallons and yielded 112 oz's of syrup and boiled it in half the time.As a small back yarder I will not boil the ice.However if it gets warm then the ice is welcome to keep the sap cold.Just my 2 cents.