Much of the following information comes from Mark Schatzker, author of the book “Steak – One Man’s Search for the World’s Tastiest Piece of Beef“. Using information from Mark we will try to answer the question, “What is the relationship between flavor and fat”?
USDA grading based on marbling fat and exterior trim fat (triglycerides), the fat we can see.
Previously we noted that the USDA grading system is based on visible carcass fat. When the grading system originated, almost all “fat” cattle were fattened on grass and forages, not on grain (corn). There are two kinds of fat in meat, what you can see is called “triglycerides” and fat at the cell level (what you cannot see) is known as “phospholipids”. Phospholipid fat is actually within the cell walls, also refered to as structural fat. Mark Schatzker describes a University test where all the triglyceride fat (marbling and trim) was removed from a piece of meat and prepared. The sample still tasted like beef. In another meat sample all phospholipid fat was extracted. When this piece was prepared it tasted like burnt hair. Obviously, the fat stored at the cell level contains the flavor we know as “beef”.
Luckily we can also “see” the potential for flavor stored at the cell level by observing the visible (triglyceride) fat. White or ivory colored fat, like the sample shown above, reflects a forage based diet. Conventional beef fat will tend to appear clear. So what is going on? Mark Schatzker thinks the rumen (special stomach found in cattle that handles grass and forage digestion) alters or changes the chemicals in pasture grass and expresses the altered plant chemicals as flavor in the beef.
Researching the topic a little further we turn to Mark Bader’s website. Mark Bader, President of Free Choice Enterprises, Ltd., explains that within the rumen, proteolytic bacteria (grain digesters) and cellulolytic bacteria (forage digesters) work side by side and compete for space. In a forage based diet, the cellulolytic bacteria thrive and carry out their work and acetic acid production increases. This increase in acetic acid promotes high solid fat (white marbling) in meat. When proteolytic bacteria dominate the rumen in a high grain (corn) diet, “greasy” fat accumulates over the muscle (clear fat).
Mark Bader comments confirm Mark Schatzker thoughts on the difference between bland tasting grain fed beef versus flavorful grass-fed beef. Mark Schatzker goes on to say we cannot stop at the diet of the animal. In addition to a forage based diet, just as important, is TIME. Immature fat (animals harvested young) will have a definite “off-flavor”. Harvesting mature animals is a must for excellent flavored meat.
Looking for excellent flavored beef? Look for animals raised primarily on a forage based diet and allowed to mature. Remember, when USDA setup the protocol for “PRIME” beef, cattle were harvested after they fully matured from a forage based diet. Consider seeking out beef raised like grandpa use to and they will taste like beef should.