Wash soy beans and soak in plenty of water for at least 8 hours or overnight.
Boil 7 1/2 C water in a large non-stick pot. Let the water come to a boil then turn down heat to simmer.
Divide drained beans in 2 equal portions. Using a blender, blend one portion of beans with 2 C hot water until very smooth and pour this into the non-stick pot containing 7 1/2 C boiling water. Repeat with remaining beans and 2 C hot water.
Place a colander over a large bowl (I usually have two bowls ready for this to pour the extra soy milk if the first one gets too full). Colander should be lined with cheese cloth (may have to double line if thin) or preferably cotton straining bag.
Carefully ladle the hot mixture into the cheesecloth. Be careful, it's very hot. Wear rubber gloves. Once all the mixture is ladled in, twist cheese cloth closed and with a canning jar extract soy milk by pressing down. Make sure the cheese cloth is always closed to prevent grated soy beans or okara from falling into soy milk. Pick up the twisted cheese cloth and continue to knead it to extract the milk. Now you have soy milk in the bowl and okara left in the cheese cloth. Use okara for other uses.
Pour the soy milk into a wide non-stick pot and heat the soy milk to 175°F or 79.5 C slowly. Once you reach the temperature, it takes about 7 minutes for yuba to form. Don’t rush it.
Trim film away from the pot using a small knife and with your fingertips lift up one edge of yuba and insert a long chopstick underneath to lift up. Drain over the pot for a few seconds. Repeat until soy milk is all used up. What’s left in the pot is red film known as amayuba. Scrape this off too with spatula.
Roll each yuba into rolls.
Variation: Half formed yuba takes 4 to 5 minutes steaming before the yuba has had the chance to attach to the sides of pot instead of 7 minutes steaming . Using your fingertips or chopstick lift the yuba (very delicate) and serve immediately.