In this video I show a very common escape the Coffee Grinder.
I have seen this move used a lot in both grappling competitions and in MMA. It can be very effective when used correctly or lead to a broken arm when a few key points are missed or skipped.
The most important thing that you need to realize about this escape is that it should be your last line of defense in defending the armbar. I see a lot of guys use this as a primary escape and it makes me cringe because against an elite level grappler it is possible to do this move 100% correctly and still get submitted. With this in mind, be prepared to tap verbally, and with intensity, if the need arises.
I love the way that some people have thought this previously where they emphasize the thumb into the hip and I agree that is a very important aspect of this move that changes the orientation of the elbow but I think the most most important technical aspect of this move comes in the elevation of your shoulder.
When you understand how the armbar works and how the leverage is applied it becomes a little clearer on how to defend the position. The whole escape is not about changing the orientation of the elbow, because your opponent can easily change the orientation of the pressure. What I prefer to do is take my shoulder and continue to elevate it past the elbow which will in turn make it very difficult for my opponent to apply maximum pressure.
For a more detailed explanation of what I mean please reference the video to get a visual explanation along with the verbal.