One secret to good soup is gelatin. As the tough connective tissue in meat (collagen) denatures, it forms gelatin and becomes tender. This gelatin leaks out into the surrounding liquid and enhances it -- It contributes a mouthfeel of richness and is often used as a healthy fat substitute (gelatin is just denatured glycine-rich, triple-helix protein strands -- I know I'm nerding out).
A soup that has been slow cooked for a long time will have tender meat as well as a gelatin rich base. When you open a can of good soup, it may appear thick and gelatinous (like jello) but becomes thin once you heat it. Another example is the jelly found in the bottom of Spam. What if we want to mimic the quality of a good soup but not spend all day cooking? Why not just add unflavored gelatin to soup, gook, or jigae? -- Do NOT add flavored JELLO!
So what does it taste like? It doesn't really change the flavor, but makes it feel less water-y and more substantial. A gelatin rich soup sits well in your stomach and gives you that warm comfortable feeling. I debuted a recipe at the A2F snow trip last year and after playing in the snow, this beef barley soup was really popular (I made 15 gallons!)
You can purchase packets at Safeway or you can buy a 16oz can for about $10 at smart and final. I'll post recipes using gelatin in the future -- keep an eye out for them!