I have a pepper plant which is probably Chocolate 7-Pot.
One day, the single pepper it produced this year turned from green to brown. Does this mean it's ripe already, or does it go through several stages of ripeness?
Edit: I have finally harvested the pepper. Its color changed from pure brown to brown-red and it burns like the dickens! Maybe the red and brown pigments appear at different times with the brown color appearing a bit sooner than red.
If it's brown, it's probably not going to change color again. It's ripe. You can save the seeds and eat it.
Many hot peppers, though not ripe when green, are still usable for culinary purposes when green (some may taste better green, or some color that isn't their final color)—but you'll want to wait until they change their final color (or at least start to do so) before you save any seeds.
I've never heard of a pepper with chocolate brown as something other than the final color it ripens. (Although brown-ripening peppers can ripen red or reddish brown sometimes, and not to full-brown at all; whether they're red or brown, they're still fully ripe.) If you leave the peppers on longer, the ripening process may continue and possibly lose or gain flavor (but the color should stay pretty much the same, and it's still ripe when it first changes the final color). If you leave it on too long, some of the seeds may rot.
Plus, the link you provided at Cayenne Diane's does mention that the fruit turns brown when it's ripe: "Ripe pods are brown in color, with the white internal membrane covering much of the inside of the pepper."
Most sellers of peppers that go through multiple color phases seem to me that they advertise the fact, since it can be a selling point (although maybe not all of them).
Although there probably are several, I haven't heard of many Capsicum chinense peppers (especially among the super hots) that have more than a 2-color ripening cycle. Usually those seem to be other species.
So, in summary, I suppose it's possible it might change other colors and that it's not ripe (I don't know all things, after all)—but, from my observations and experience, it seems very unlikely. It would have to turn brown again after it changed another color for that to be true (since the description says it's ripe when it's brown).
Now, if it's merely a tan-brown rather than a chocolate brown, then I'd wait, if you want to save seeds.
Peppers do have stages of ripening. First green, then light green, then yellow, then red or brown...depends on the pepper. Peppers will ripen after being plucked off its mother plant when they are plucked at a certain stage. I've not yet found a too green stage for peppers to continue ripening in the kitchen. Once you see any change in color of the pepper it should be able to be harvested and brought indoors to ripen further.
If you don't have to worry about a freeze, leave the peppers on your plant to ripen. If you take the peppers off as soon as possible, that plant will be able to produce MORE peppers, other peppers will ripen sooner.
You said you had but one pepper? Is this in doors? Out of doors on the patio? In the garden?
The main reason this happens is that people fertilize with too much nitrogen in relation to the phosphorus and potassium. You'll get lots of healthy vegetative growth and few flowers/few fruit. The difference could be a formulation for example of a 5-4-4 fertilizer. Or using compost and then using a 4-4-4...too much nitrogen with respect to phosphorus and potassium. Or using fish emulsion and a balanced 14-14-14 fertilizer. Too much nitrogen.
The other reason is lack of light. One needs an awful lot of light to grow flowers and fruits (vegetables). If you are growing inside near a window you are lucky to get one pepper. Daylight length is another important aspect to encourage more fruit...depending on the plant, most vegetables need a noticeable reduction of daylight length; going from 18 hours of daylight to 12. That reduction is an important signal to the plant to get its job of reproducing done before the first frost.
