Shiny or Dull? Which side of aluminum foil should you use for packing food? Truth will surprise you

For many years, people have been using aluminum foil as if it came with a secret kitchen language. The surface is either glossy on one side and matte on the other side, and it is through this minute difference that the most persistent myth was developed by people. According to some, one of the surfaces allows food to cook faster, to be warmer, or to reflect more heat. In turn, others argue that there is a "right" way of using foil when roasting, baking, or covering up leftovers.

However, according to Reynolds Wrap, there are no secrets to this myth. As it appears, for normal aluminum foil found in every house, it does not matter which side you use. The truth behind the myth is much simpler than the folklore.

Why do people think the sides matter?

This is one myth that has lasted due to its plausibility. There are many little techniques in cooking and traditional wisdoms, which make the notion of the different functioning of one side of the foil credible.


Most people believe that one side is better at reflecting the heat while the other side absorbs heat. Another myth says that the foil with the shiny side must always be outside in order to keep food warm or inside in order to make the food cook faster.
As described by Reynolds' aluminum foil guide, however, both standard and heavy-duty foil may be used on both sides when cooking. Reynolds explicitly states that "there is no difference" between the sides in terms of performance during regular cooking. Thus, it makes no difference if one wraps the casserole dish, the baked potatoes, or lines up the sheet pan.

What actually creates the shiny and dull sides

The difference is purely a result of the manufacturing process and not the cooking surface itself.
Reynolds explains that aluminum foil is manufactured by layering aluminum sheets together and then milling them down to be incredibly thin. In the final rolling process, the two sheets go through the mill simultaneously; the side that is processed by the rollers will be shinier than the side being compressed into the other sheet. Reynolds heavy-duty foil
In other words, there really is no difference.

This detail is important because it dispels one of the many misconceptions that are spread around the Internet regarding food preparation. Even though the shiny side appears to be more reflective, its impact is negligible when cooked in an average household oven.

Cooking techniques such as heat transfer, cooking temperatures, proper sealing of food, and correct thickness of aluminum foil are far more critical than which side you use.

The one-time foil direction actually matters

There is one significant caveat that makes the discussion continue. Non-stick aluminum foil is distinct from ordinary aluminum foil. In the cooking guidelines for non-stick foil from Reynolds, it is stated that the dull side is the one with the special coating and must be placed next to the food.

This is why many people have their minds made up about which way foil needs to be oriented when cooking, especially when preparing sticky foods like marinated chicken wings, baked fish, or sugary vegetable dishes. In most cases, they were probably informed of how to use non-stick foil and incorrectly assumed that all foil must be used in the same way.

However, non-stick foil and regular aluminum foil are two separate products.

What matters more in real cooking

In their opinion, people pay too much attention to something unimportant regarding how the foil should be used. Actually, whether to use the shiny side up, down, or otherwise does not matter as much as choosing the right foil for the job.

Heavy-duty aluminum foil will be needed for grilling, freezing, and covering heavier foods, while for ordinary baking, food packaging, and pan-lining, the regular foil would do fine. There is even foil available for cooking foods that are likely to stick easily.

In the opinion of Reynolds' experts, making sure you are using the right kind of foil is a lot more sensible than fussing about whether the shiny side goes up or not. There are also some cases where aluminum foil should be avoided altogether. In some instances, foods are too acidic to be cooked with aluminum for extended periods of time, while other kitchen gadgets might warn about the dangers of using aluminum foil.

These are the details that matter.

Why this myth refuses to disappear

This myth about aluminum foil perfectly fits into the category of everyday myths that have gained popularity on the Internet. It concerns a household item, a visual cue, and an underlying "scientific trick." However, the reality is quite clear.

When it comes to standard aluminum foil used in households, the glossy and matte sides do not differ in terms of their performance when cooking. It is the production process that causes the differences in foil sides, not its performance features. If there is no marking indicating non-stick properties, you should cease pondering over which side goes up and which side down.

The main lesson here is not to complicate what can be done quite simply.