That’s because they retain more moisture after curing, and therefore reflect more light. Roast beef isn’t cured, but deli beef is often lightly brined for flavor and moisture retention. Second, perfect slicing — and the smooth surface it produces — accentuates the rainbow effect.
Roast beef isn’t cured, but deli beef is often lightly brined for flavor and moisture retention. Second, perfect slicing — and the smooth surface it produces — accentuates the rainbow effect. You’ll seldom see it at home, but in the deli with its high-speed slicers, it’s common. Third, some meats are more prone to producing rainbows.
The colorful sheen on a slice of roast beef or pastrami isn’t a sign of spoilage or chemical additives—it’s actually a result of the way the meat is cut. Slicing meat “against the grain” means cutting through, rather than parallel to, the bundles of fibers composing the meat’s musculature.
What are meat Rainbows?
Take so-called “ meat rainbows ”: They happen when a slice of deli meat takes on an iridescent shimmer reminiscent of an oil puddle in a parking lot—a., and k., and a. Not something you want on your sandwich.
According to the USDA, “When light hits a slice of meat, it splits into colors like a rainbow.” This is something called a “diffraction grating,” essentially what happens when light waves bend or spread around a surface and create a pattern.
Cause of shiny, rainbow appearance on some cured meats. A natural phenomenon in cured meat (and some fresh meat) is the occurrence of iridescence or a rainbow appearance on the cut lean surface. Technically, this is referred to as birefringence. It is caused by the reflectance of light off of muscle proteins, and it is analogous to.
Why does cooked meat turn red when cooked?
The color of the meat matters. Dark cooked meat like roast beef and bright cured meat like ham are more likely to show iridescence because the background colors provide a starker contrast to the pearly greens and orangey reds that you’re most likely to see coming off of shiny meats.
What are iridescent shimmers in meat?
Iridescent shimmers are easier to spot on darker meats like beef and some pork —so if you’re eating a slice of turkey from the deli, it could be covered in meat rainbows you don’t notice. We’ll let you decide if that’s a positive thing.