Saturday, 14 May 2016

09:59 – Barbara and I just hung the final few pictures in her office and installed a shelf in the laundry room over the coat rack. I’m making up chemicals in there now, and I need somewhere to store the large beakers, graduated cylinders, and other stuff I use for that.

We’re going to repackage some LTS food today, including the 50-pound bag of sugar we picked up at Costco Thursday and some baking soda. At room temperature, the stuff is stable essentially forever in the retort bags it comes in, but it’s a PITA to haul out and open a 13-pound bag of baking soda every time we need a teaspoon or two. We’ll repackage it into Costco nut jars, which hold about two liters. The density of powdered sodium bicarbonate ranges from 1.1 to 1.3 g/mL, depending on how tightly packed it is, so we should get five pounds or so in each jar.

Incidentally, if you’re storing baking soda, which you should be, that “room temperature” part is important. I’ve seen people store those big bags in the garage or attic, which is a bad idea. At higher than room temperature, baking soda starts to break down into sodium carbonate and carbon dioxide gas. At about 50C, it breaks down very quickly. I’m comfortable storing it at up to 86F (30C), but I wouldn’t go much higher.

Same deal for baking powder, but more so. Baking powder is a combination of baking soda and a dry acid. It degrades very quickly at high temperatures, and even faster if moisture is present, even from humid air. In fact, baking powder is unstable enough that we don’t store any in our long-term supplies. Instead, we store baking soda and citric acid. Both of those are very stable if stored separately, and it’s easy enough to combine them to make up your own baking powder on the fly.