There are two main ways to tell when ribs are done. They are, in order of most importance:
Regardless of the type of rib you're smoking, these factors are universal.
While there are certainly other methods that can be used to determine if ribs are "done," they are not nearly as reliable as being probe tender and within a specified temperature range.
In my opinion, probe tenderness is the best way to know if ribs are considered done.
The term "probe tender" refers to using a temperature probe to poke between the bones in order to feel how the probe penetrates the meat.
If the probe feels like it's sliding through hot butter, the meat is considered tender. If there is any sort of resistance, the ribs need more time on the smoker.
Keep in mind, this method assumes you're using an instant read thermometer, hence probe. You can easily use a tooth-pick or similar tool to poke into the meat and test tenderness.
Note: The instant read thermometer/probe I use is the ThermoWorks Thermapen MK4.
The internal temperature of meat can give you a general idea of doneness. Meaning, we know that the meat has been cooked to both a food safe temperature and is tender.
The USDA outlines specific temperatures where-in meat is considered safe to eat:
|Meat||USDA Safe Temperature (F)|
While at these temperatures meat is considered safe to eat, it does not mean that the meat is tender.
At 160F collagen starts to dissolve (connective tissues) and at 180F they're fully dissolved. While there is less moisture than meat below 140F, the rendering of collagen creates gelatin which adds succulence. Meaning you get tender, succulent meat.
At around 195 - 205 F, the collagens and fat have rendered and the meat is tender. However, internal temperature should not be solely relied upon to qualify if ribs are done.
If you were to temperature probe the ribs and they said 198, but they didn't feel probe tender, they are not done. You need to continue smoking until the meat feels done.
As with any topic in barbecue, there are a number of opinions and methodologies. However, there are issues with these approaches that I'll outline below.
Color can be a good indicator for various stages of smoking. For instance, on pork ribs I use color as a way of telling me when to wrap. After I see that the dry rub has adhered to the meat and upon touching it - if it no longer sticks to my fingers - I know it's time to wrap.
Color is also a sign of the maillard reaction of sugars as well as smoke. For instance, cherry wood gives pork and beef a nice ruddy mahogany color; The maillard reaction of sugars results in browning.
Visually, you can also see char form and develop. In this case, color is useful as it gives you an action plan for how to prevent meat from burning.
For example, in some cases a brisket flat may finish before the point. By turning the brisket away from the direct heat, or even wrapping the flat, you can deflect heat and slow down the cooking process.
With all that being said, color doesn't really give you much other than these indicators. Meaning, color alone won't tell if you if your ribs are done.
The the phrase "visual pull-back from the bone" is super common - it describes the protrusion of the bones as the meat "pulls-back."
The pull-back occurs because the meat is physically shrinking as it's being smoked. When meat is smoked, the fibers are being contracted and juices are forced out.
While pull-back is a good visual indicator that the meat is cooking properly, it still does not tell you if the meat is done.
The above image is a good example of why it's not an indicator of "doneness." The ribs above have different thicknesses of intercostal meat (between the bones) meaning, one side is going to finish before the other. If we were to solely use "pull-back" as an indicator of doneness, some parts of the rib may not even be tender.
Some people even equate the pull-back to be similar to that of Pop-up Timer that's used for turkeys. However, this doesn't make any sense as the pull-back/shrinkage on ribs can occur at various temperatures. Where-as the Pop-up Timer is an engineered product that uses metal that melts at 165 F indicating doneness.
A common test that experienced Pitmasters and enthusiasts use is the bend and/or twist test.
The bend test involves picking the ribs up at one end with tongs at the center and allowing gravity to physically pull the meat downwards. If the ribs are ready you'll visually see cracks occur at the bend; The bend should be close to breaking but not break.
The twist test is similar to the bend test. A rib bone at the center is twisted in such a way that when you twist you can feel the bone break free from the meat.
While I also use these tests, unless you're experienced you may not know what to look for. I personally messed this up the first time I smoked ribs. I assumed the small crack at the bend was enough, only to find out it could of gone further.
I hate this concept so much that I wrote an entire article on it: The 3-2-1 Rib Method and Why You Shouldn't Use it.
Put simply, a number of people like to use time as a means to estimate when ribs are done. However, this doesn't account for the size of the meat, the smoker being used, type of rib, ambient temperature - Granted it does assume you're smoking at 225F.
A huge issue with this method is that you could end up with overcooked ribs. Truth be told, ribs shouldn't entirely fall off the bone. Ribs should be smoked to the point that they pull cleanly off the bone when you bite into them.
Keep in mind though, I'm not you; What I may like, you may not.