August 25, 2009
Anyone who’s thought about the environmental cost of the various products we consume, from plastic spoons to produce to toys, has thought about the costs involved in shipping these times. If you’re like me, you might think about the fossil fuels required to move a teddy bear from China to Pennsylvania: the gas of the truck from the factory to the shipping yard in China, the diesel of the ocean liner from China to Los Angeles, and then more gas for the truck from LA to Philadelphia. Usually, the longer the journey, the more environmentally expensive it is.
What many don’t consider (or at least not me) is the requirements of some products, especially food, in that transportation. For example: ice cream. It must be made, stored at the factory, shipped, and then stored at our grocery store all at freezing point. As you know, keeping food this cold requires a hefty amount of energy in addition to that required simply to transport it. Thus, as the Times of London and Scientific American report, Unilever (which owns Ben & Jerry’s) is embarking on the crazy-sounding idea of making ice cream that’s made, shipped, and stored at room temperature only to be frozen once you put it in your own freezer.
While the science behind fat, sugar, and consistency has been studied for a good while, it still sounds crazy. I’m quite skeptical that they’ll be able to do it and still have it taste as good as the real deal. But, never underestimate those food scientists, who’ve been able to create ice cream that doesn’t melt (although, again, who knows how it tastes).
Although food science hasn’t really improved the quality of our food that much, it certainly has its advantages (like decently ripe fruit 12 months out of the year), many of which we’re willing to compromise a bit on taste in order to get. And once (as I hope), we start having to confront the calories (or if you prefer metric, joules) of energy the products we buy cost (as the Brits have begun to do), we may be more willing to make sacrifices in flavor for the good of the planet, just like we often do for the good of our waistline and arteries.
June 9, 2009
I was making brownies the other day and, when the recipe called for a teaspoon of baking powder, realized that I didn’t really know how baking soda and baking powder are different. Having taught high school chemistry for the past two years, I found this an egregious gap in my knowledge and so went to Wikipedia’s entries for baking soda and baking powder to get some answers.
Baking soda is a pure chemical compound, sodium bicarbonate (also known as sodium hydrogen carbonate), NaHCO3. Sodium bicarbonate reacts with acids (compounds that give off hydrogen ions in aqueous solution) to produce gaseous carbon dioxide.
NaHCO3(aq) + H+(aq) → Na+(aq) + H2O(l) + CO2(g)
Baking soda therefore needs an acid in order to produce the CO2 necessary to leaven the brownie, cookie, or bread. Ingredients like lemon juice, yogurt, buttermilk, and vinegar do the trick, but if you’re not interested in adding those to your recipe, solid acid salts like cream of tartar (potassium bitartrate, KC4H5O6) also work just fine.
Baking powder contains three main ingredients: baking soda, a starch, and acid salts. The baking soda is for obvious reasons. The starch, which is usually just cornstarch, prevents any buildup of moisture that might start the reaction and make the baking powder less potent.
The acid salts are usually a combination of two different acids, a slow-acting acid and a fast-acting acid (hence the term, “double acting”). The fast-acting acid begins the reaction right away (as soon as the solids are mixed with the liquids), and the slow-acting acid reaction doesn’t really begin until it’s heated in the oven. The double-action gives more margin for error in the time between mixing and baking. Common slow-acting (high-temperature) acid salts are cream of tartar and monocalcium phosphate. Common fast-acting (low-temperature) acid salts are sodium aluminum sulfate, sodium aluminum phosphate, and sodium acid pyrophosphate.