Yams being confused with sweet potatoes dates back to America's slavery days. In the U.S., when softer varieties of sweet potatoes became available, growers wanted them to be called something different. African slaves on plantations called the softer variety yam because it reminded them of African yams, a white, dry and starchy vegetable, and the name stuck. So yams in U.S. grocery stores are actually soft sweet potatoes, and you will likely find true yams only in an international store. Either way, both true yams and American yams can be steamed the same way.
Heat a large pot to boil with just enough water so that the water does not come into the steam basket when placed into the pot.
Wash the yams throughly and use a dish scrubber to remove any dirt and debris. Cut out any dark or rough looking spots.
Peel the yams. Cut into large chunks or leave whole if you prefer.
Place the yams in the vegetable steamer over the pot of boiling water. Cover the pot and let the yams steam for about 25 minutes. The yams are ready when they are tender when pierced with a fork.