Substituting freezer paper for parchment paper

Question

I am making a brisket and the recipe calls for coating the meat with a tomato-based rub, which means I can't simply cover with foil... that would leave an unsavory taste in the rub because the aluminum would react with the tomato paste. The recipe suggested parchment paper between the brisket and the foil; I am cooking at 200 degrees F for eight hours.

I read somewhere that parchment paper is sometimes coated with silicone; however, I also see that it's more than twice as expensive as freezer paper... locally I can buy 75 sqft of generic freezer paper for $2.50, but only 30 sqft of the same generic distributor's parchment paper is $2.68.

• Is there a good reason why I can't substitute freezer paper for this application (chemicals side facing the foil, of course)
• Also, what kind of cooking situations is parchment paper best-suited for?

Answer

Parchment paper is not paper coated with silicon. It's actually paper that's been run through sulfuric acid, leaving it just a really thick matrix of cellulose. Long story short, extremely thick paper without the wood pulp.

Freezer paper is normal paper with wax applied to one side. I wouldn't use it for anything involving heat, as you'd end up eating the petroleum-enriched waxy bit in your food, and the paper might light on fire.

Parchment is used as a spill-proof surface in baking. Additionally, you can wrap foods in parchment (a technique known as cooking en papillote) and stick them in the oven, which effectively steams them in their own juices, so no flavor is lost. Salmon and vegetables are exceptionally delicious this way.

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How does foil protect a sandwich in the [toaster] oven?

Question

If I wrap a sandwich in foil and toast it, the entire sandwich seems to warm more evenly, so I don't get burnt edges of bread.

Can someone explain what is going on here?

I assume it has something to do with the ambient temperature cooking the sandwich instead of direct heat.

Answer

I don't think it's just one thing:

1. The foil reflects radiant heat, meaning that the only remaining way to propogate heat is through conduction and convection.
2. The foil is an impermeable barrier which helps to keep the moist air (created by boiling off the moisture in the surface of the bread) near the sandwich, which reduces the rate at which the bread dries out, and we need dry items for them to burn.

It's possible that retention of the moisture within the foil slows the heating of the enclosed system as there's less loss of thermal mass, but I doubt that's a significant factor in most situations.

You might be able to test which of the other two is the more significant factor by running a test with foil that's been perforated such that it's not a good barrier but would still be reflective, and see how that compares.

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