With the right technique, making sushi rice at home is a piece of cake. Here's my step-by-step process for making the best sushi rice from scratch, just like the best sushi restaurants in Japan.
Ideally you want to let the rice sit in the water for at least 30 minutes before you start cooking it. This allows the grains of rice to soak up some water before cooking, which results in shinier rice with a better texture.
Dump the rice out into a very large bowl, the key is that you want a container with a lot of surface area so you can spread the rice out to cool it rapidly. Gently flatten out the rice and then pour the vinegar mixture evenly over the hot rice.
Use a shamoji, spatula or a flat wooden spoon to gently combine the rice and vinegar using a side-to-side cutting motion followed by a folding motion. You want to separate each grain of rice, so the vinegar penetrates every surface, but you don't want to break the grains of rice or mash them together.
While you mix the rice, hold a fan or piece of cardboard, or a clean hairdryer set to cool and blow air on the rice. This cools the sushi rice and helps the excess liquid evaporate quickly, which gives your rice a nice shine and prevents it from getting mushy. It's a bit tricky mixing and fanning at the same time, so a second set of hands can be helpful here.
The sushi rice is done when the surface is no longer wet and slippery, the rice is fluffy, and each grain is very shiny. It will still be a little warm, but it should not be hot.
Mound up the rice, and cover with a damp towel until you're ready to use it.
A rice cooker cup does not equal 1 US cup. If you don't have a rice cooker, use the weight measure.