TEST KITCHEN: We answer that pressing question: Should the shiny side be in or out?
By DANIELLE CENTONI
Special to The Oregonian
It's a question for the ages, one that has spawned heated debates and much eyebrow crinkling: shiny side or dull?
We're talking about aluminum foil, of course, and the famous question that has vexed everyone at one time or another.
The answer? It doesn't really matter.
Makers of aluminum foil don't intentionally make a shiny and a dull side for any culinary purpose. It's merely a result of how the foil is made. Sheets of aluminum are rolled between polished steel rollers time and again until the aluminum is pressed to the desired thinness. The foil we use in the kitchen is so thin it's prone to tearing, so for the last rolling, two sheets are passed through together. The sides that face the rollers get shiny, while the sides that face each other come out dull.
That said, this byproduct of manufacturing does, technically, give one side a very slight edge over the other in terms of cooking and retaining heat. The shiny side is a better reflector of heat. So, if you wrap your food with the pretty side out it might cook ever so slightly slower. By the same token, when the shiny side faces the hot food it can help reflect its heat and retain it, thereby keeping those foods warmer for slightly longer. So, if you must know, dull side out is slightly preferable, but the difference is so small, really, it doesn't matter.
There are actually more important questions concerning aluminum foil:
Q:
Why is it sometimes called tinfoil?
A:
It shouldn't be. The precursor to aluminum foil was made with tin because aluminum was too expensive to extract. But the technology improved by the turn of the 20th century, making aluminum cheaper and the foil material of choice.
Q: Why does aluminum foil sometimes melt and leave black specks on food?
A:
It's so unsettling: Cover a lasagna with foil -- or even the cannelli dish on Page FDX -- and the foil might end up looking like swiss cheese.
According to the Reynold's Wrap website, "when aluminum foil comes in contact with a different metal or a food that is highly salted or acidic, small pinholes are formed in the foil. This is a harmless reaction that does not affect the safety of the food."
Reynold's says a reaction happens when aluminum foil comes in contact with salt, vinegar, highly acidic foods -- such as tomatoes -- or highly spiced foods. The foil seems to dissolve or get eaten away, but what happens is it turns into an aluminum salt. Aluminum salts, like sodium aluminum phosphate, are found in many processed foods. Most scientists do not consider aluminum toxic. The Reynold's website says: "The food can be safely eaten; however, the aluminum salt particles can be removed from the food to improve the appearance of the food."
If the aluminum reaction bothers you, in many situations you can put parchment paper between the food and the foil.
The company says this can also happen when aluminum and another metal are in contact with each other in a moist environment, leading to a reaction that causes a breakdown of the aluminum. To avoid this unsavory occurrence, use aluminum, glass, ceramic, plastic or paper containers with foil. Do not cover sterling silver, silverplate, stainless steel or iron with aluminum foil.
Q: Why does foil darken or discolor sometimes during baking?
A:
That discoloration is aluminum oxide, a harmless substance that is naturally present on the surface of the foil. When the foil comes in contact with moisture, it can accelerate the buildup of aluminum oxide.
Q: Can using aluminum foil cause Alzheimer's or other neurological diseases?
A:
It depends on who you ask. Naturopathic types would argue yes, but the western medical establishment would say no. According to food scientist Robert Wolke, some people have suspected a link between aluminum and Alzheimer's, Lou Gehrig's and Parkinson's diseases for about two decades, but it has not been proved. Besides, most of our aluminum intake comes from our food and water, not the foil we use. Aluminum is the most abundant metal in the Earth's crust and is widely distributed in soil, plants and water. Our bodies absorb less than 1percent of what they take in.
Q: Can foil be recycled in the Portland area?
A:
Yes. Just be sure to rinse it thoroughly. And if you lean toward green, you might want to check out Reynold's new 100percent recycled foil packed in 100percent recycled paperboard (
).
Danielle Centoni
is a freelance writer and former FOODday staffer.
If you purchase a product or register for an account through a link on our site, we may receive compensation. By using this site, you consent to our User Agreement and agree that your clicks, interactions, and personal information may be collected, recorded, and/or stored by us and social media and other third-party partners in accordance with our Privacy Policy.
