The myth, the legend: shortening.

A few weeks ago, I wrote a post on Feeding America, an amazing website (courtesy of Michigan State University) that provides high resolution scans of very old cookbooks (warning:  Feeding America is major derailer; if you have real work to do, best leave it alone).

I've been looking through several of the older cookbooks (pre-1920), and the curiosities in them are endless.  Desserts are king -- sometimes, half of the book is dedicated to cakes and pies (how much of this stuff did they used to eat?).  And just about every dessert requires an ingredient that we see less and less of today:  shortening.  Which got me wondering -- why do they call it shortening?  Why not just call it fat?  Where did the term shortening come from?

So off I went on mission to find out.  I consulted a few cookbooks (modern, that is), the web (the usual suspects:  Google, Wikipedia, et al) and McGee's On Food and Cooking.  Here's what I learned about the legendary shortening:

• Shortening (i.e. fat) refers to the effect it has on pastry dough, in that it results in a "shorter" baked product.  A shorter (or short) baked good is one that's tender, crumbly (not short in height, or size); hence:  shortbread, shortcake and short crust.  The word short, in fact, used to mean weak or pliable.
• Shortening has appeared in recipes for the last five- to six-hundred years; OED traces usage of the word as far back as the 15th century
• In 1911, Crisco hydrogenated vegetable oil was introduced to consumers; prior to this innovation, shortening consisted of a mixture of butter and lard
• Today, we know that shortening works by interfering with the wheat flour's ability to form long chain protein (gluten) strands, keeping them shorter and weaker...which is an interesting coincidence, considering that 600 years ago, our ancestors knew nothing of long chain proteins. 
• An example of a shortening/fat in action: a traditional baguette has no added fat/shortening and has a chewy, relatively tough texture (long chain proteins). However, a biscuit, composed of essentially the same ingredients as the baguette, does have fat/shortening (butter, lard, Crisco, etc).  The shortening gives the biscuit a light, fluffy, even crumbly texture (caused by weak, shortened protein chains) .
• A bit of a side note: many people believe that shortening (e.g., processed vegetable oil) produces pastry that's superior to lard or butter.  Part of this may be due to the fact that gas bubbles play an important role in the texture of pastry -- the more small gas bubbles, the more tender the crust.  McGee points out that modern shortening has a different structure than animal fats, allowing smaller bubbles to form and remain in the dough during baking.  Also, he notes that manufacturers "fill shortening with preformed bubbles of nitrogen (around 10% of the volume) and bubble stabilizing emulsifiers u(p to 3% of the shortening weight)."  Personally, that's enough to make processed vegetable shortening a deal-breaker (and I won't even get started on hydrogenation.)

For a fascinating etymology/history lesson on shortening, check out this post:  The Origins of Shortening