Let them eat... play-dough?
My children eat play-dough. Shamelessly, persistently and with gusto. So I decided early on that instead of denying them the pleasure of squeezing, burying, cutting, stamping and rolling play-dough, I would give my two boys (ages 2 and 4) homemade dough instead of the kind that comes in canisters.
(Commercial play dough is technically not toxic, but it is not intended to be eaten, and contains lubricants which are probably petroleum based, as well as preservatives. Here's a good article about the science behind it.)
We make play-dough on a weekly basis, often from the same recipe, but sometimes from recipes online. The quality and texture of these online recipes vary widely. One week our play dough might be perfect, another too crumbly and dry, and sticky and gooey the next. The nerd in me wondered what made them turn out so differently, and the mom in me was sick of vacuuming crumbled play dough and scraping gluey formulations from my chairs.
So, inspired by Cook’s Illustrated, I decided to try dozens of play-dough recipes, using friends as testers, to isolate the best recipes.
The science behind play-dough
Play-dough contains five basic ingredients: flour, water, salt, cream of tartar (or other acid) and oil. The variables that most affect texture are the cream of tartar, salt and the type of flour used. The flour and water compose the bulk of the dough, and most recipes I found contained equal amounts of flour and water. The proteins in the flour (gluten for wheat flour) interact with the water and heat to become a stretchy, elastic mass. Salt acts as a preservative, and also adds texture and body to the dough. Oil acts as a lubricant, and helps to keep the dough moist and not sticky.
I had no clue what cream of tartar is, except that I knew it made snickerdoodles tasty. Turns out, cream of tartar (potassium hydrogen tartrate, also known as potassium bitartrate) is a byproduct of wine production, forming inside wine barrels during fermentation. Cream of tartar is an acid, and is used in cooking as a stabilizing agent for meringues and whipped cream.
This article was originally published on April 15, 2013, and updated on March 27, 2017.