Glucose: Potato Starch Boiled with Dilute Sulfuric Acid

Boiled in water with a little sulfuric acid, starch turns into glucose, the sugar of grapes. Payen's factory method, printed in Muspratt's chemistry: starch let into boiling acid water, tested with iodine until it no longer turns violet, the acid taken out with chalk, the syrup cleared through bone black and boiled down until it sets. The picture: glucose (dextrose monohydrate) powder in a weighing boat.