Comparison tests are always revealing, but this one proved a real surprise. I tried a second batch to be sure the results weren’t fluky. When cooked with its peel, the purple yam was fibrous, wet, bland, and mottled in color, and it lost a good deal of flesh in post-cooking peeling. When cooked without its peel, the flesh was uniformly red-violet and mildly sweet with gentle smoky, meaty, and nutty hints. It was smooth and juicy in comparison with other yams, and remained moist and soft even as it cooled.