Frequently Asked Questions : Reynolds Wrap® Aluminum Foil

Frequently Asked Questions

Which side of Reynolds Wrap® Aluminum Foil should I use, the shiny or the dull side?
Actually, it makes no difference which side of the aluminum foil you use—both sides do the same fine job of cooking, freezing and storing food. The difference in appearance between dull and shiny is due to the foil manufacturing process. In the final rolling step, two layers of foil are passed through the rolling mill at the same time. The side coming in contact with the mill's highly polished steel rollers becomes shiny. The other side, not coming in contact with the heavy rollers, comes out with a dull or matte finish.

The exception is when using Reynolds Wrap® Release® Non-Stick Aluminum Foil. The non-stick coating is applied during manufacturing to the dull side of the foil. Always place the non-stick (dull) side toward the food.

Which is better for freezing, aluminum foil or plastic?
Aluminum foil has the lowest moisture-vapor transfer rate of all wrapping materials. This means that it is the most effective in preventing the loss of moisture and vapor from the food. This is the reason why foil is preferred over plastic wrap for long-term food storage or freezing.
 
How do I know which aluminum foil to use?
Standard aluminum foil is an excellent for wrapping sandwiches, covering bowls and containers with lost lids, wrapping all sizes of vegetables for the refrigerator, or reheating pizza in oven or toaster oven. Heavy duty aluminum foil is better for wrapping meats and poultry for the freezer, lining roasting pans for easy cleanup, lining the inside of a charcoal barbecue grill to keep it clean, tenting roasted turkey to prevent oven spatters and over-browning, and making an oven packet for cooking chicken, fish and vegetables. Our extra heavy duty foil is great for making campsite cooking utensils, lining the inside of a charcoal barbecue grill to keep it clean, and wrapping large meats and poultry for long-term freezing.
 
Can I line the bottom of my oven with aluminum foil?
To avoid possible heat damage to your oven, we do not recommend using aluminum foil to line the bottom of your oven. Rather, we recommend that you place a sheet of heavy duty aluminum foil on the oven rack beneath the pie or casserole you are baking. The foil should be only a few inches larger than the baking pan to allow for proper heat circulation. The foil will catch any drips before they reach the oven bottom.
 
Why does my foil darken or discolor sometimes during baking?
The darkening of foil may be caused by moisture from the food being covered. This results in a buildup of aluminum oxide. This is a totally harmless substance that is naturally present on the surface of foil. Moisture tends to accelerate this buildup.
 
Why does aluminum foil sometimes melt and leave black specks on the food?
Occasionally 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. It is difficult to predict, but may occur under the following conditions:

1. When aluminum and a dissimilar metal are in contact in the presence of moisture, an electrolytic reaction may occur causing a breakdown of the aluminum. To avoid this use aluminum, glass, ceramic, plastic or paper containers. Do not cover sterling silver, silverplate, stainless steel or iron utensils with aluminum foil.

2. A similar reaction may occur when salt, vinegar, highly acidic foods or highly spiced foods come in contact with aluminum foil. The result of these reactions is a harmless aluminum salt. Some aluminum salts are used in medicines to treat stomach disorders. The food can be safely eaten; however, the aluminum salt particles can be removed from the food to improve the appearance of the food.
 
Why is aluminum foil sometimes called tin foil?
In 1919, the U.S. Foil Company, parent of Reynolds Metals Company was founded in Louisville, Kentucky to produce lead and tin foil. Then in 1926, the company entered the aluminum business, rolling aluminum foil for packaging. Today, Reynolds Wrap is made from 8111 alloy aluminum, at the thickest gauge specifications available in the marketplace. Reynolds Wrap® Aluminum Foil is 98.5% aluminum. The balance is primarily iron and silicon. These are added to give the strength and puncture resistance obtained only in the alloy used in Reynolds Wrap® Aluminum Foil.