Green tomatoe - how to tell if they are ripe?

[Zootal]

I've been looking at some heirloom green tomatoes - tomatoes that are green when they ripen. Has anyone here grown these? How is the flavor, and how do you tell if they are ripe?

[Jean B.]

I grow green zebras. The stripes are kind-of golden when they are ripe. I have no idea how one would tell on a purely green one.

[Billy]

When ripe the stripes become distinct and the tomato loses its' billiard ball hardness.

[JoeSpareBedroom]

Feel it, smell it.

[KarenCannoli]

I grow them also. They tend to have a slight tang to them. I also harvest when they get a little gold tinge to them. K