This is the stage that can best be enjoyed on a cold day. How nice it was to cozy up to the fire and breathe in the maple syrup steam while the cold wind blew outside or the rain came down! Grandpa has a chair and a splash guard that he sets up on those days, so he can get nice and close and stay warm.
To boil down the sap, Grandpa Nutbrown lights a fire in the stove under the 4 tubs and begins the flow of fresh sap into the first tub. Here it warms up and continues flowing from tub to tub until it is in the fourth tub where it becomes maple syrup (or pretty close to it).
Next we got the fire going again to get the last tub as close to syrup as possible. Grandpa shut off the pipes between the third and fourth tub and unscrewed them, so we could work on just the fourth tub getting pure. Grandpa watches the bubbles on top of the fourth tub. They start out looking like tiny bubbles, like foam, on top, but as it gets closer to syrup, the bubbles get bigger, like those in the picture below. At this point Grandpa gets out his dipper and scoops up some syrup and then lets it drop back into the tub. He is looking for a web coming off of the dipper, which tells him that the syrup is ready to take off the fire.
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