Know Your Fat! (Part Deux)

That is what I'm talkin' about!

When last we spoke, I talked just a bit about butter, shortening, lard and oil as fats used in baking.  Not only do all four of these products look, taste and smell different, they also behave differently in baked goods.

For the purposes of a post of reasonable length, and also because oil and lard are used less frequently than are butter and shortening, let’s just look at those two and the way substituting one for the other can effect a final product.

As I said in Part 1, butter has some water in it, along with some milk solids.  It is very firm under refrigeration but is nice and plastic at about 68 degrees, F.  Once it starts to melt, it melts very quickly.  Shortening, on the other hand, is 100% hydrogenated vegetable fat.  It behaves about the same at refrigeration temperatures as it does at cool room temperature.  It begins to melt at a slightly higher temperature than butter, and it tends to melt more slowly.

So what?  Well, let’s say you’re making some oatmeal cookies.  You make 1/2 with butter and 1/2 with shortening.  The ones you make with the butter will be crisper at the edges and a little chewy, will spread a fair bit and will be nicely browned.  The ones you make with the shortening will be softer and puffier, a bit lighter in color, and they won’t spread as much.

This is why: the water in the butter mixes with the flour in the recipe, forming some gluten.  Gluten=chewy cookie.  The butter melts to a thin liquid quickly.  Melted fat=lots of spread=thin cookie.  The milk solids brown in the oven.  Browned milk solids=well, you know, brown cookies.

Since there is no water in the shortening to mix with the flour, there won’t be any gluten development, and you’ll get a more tender cookie.  Since the shortening melts at a higher temperature and more slowly than butter, the cookies will tend to hold their shape and be puffy, rather than thin.  No milk solids to brown=lighter cookies.

I’m not a fan of shortening, although if you want to refrigerate your cookies, they won’t get too hard if you’ve made them with shortening.  I like the way butter tastes.  The way it behaves is part of its charm.  Knowing how it behaves gives us some power to make it behave the way we want.

If you use all-butter but don’t want a thin cookie, refrigerate the dough before baking, and make sure you’re baking on a cool cookie sheet.  If you have to re-use a sheet, make sure you let it cool before placing more dough.  If you want a thinner cookie, have your dough closer to room temperature.  If you’re portioning your cookies with a disher, make sure to press down on the balls to flatten them a bit.  They’ll spread more evenly if you do.

I thought two parts was enough.  But I have ideas.  Part Trois coming up later!  Don’t be shy–leave a comment.  Butter or shortening?  Cookies or cake?  Whatever is on your mind (within reason)!