986
xkcd #2893: Sphere Tastiness
(imgs.xkcd.com)
Alt text:
Baseballs do present a challenge to this theory, but I'm convinced we just haven't found the right seasoning.
Ice bergs. They are kinda round (less so with larger ones) and they are freshwater so entirely edible. According to the graph the object would taste "ok" which is a perfectly adequate description of drinking water.