Yesterday’s kitchen science experiment was this morning’s breakfast! In explaining to my young son about microorganisms that we live with (in our bodies, and as tools of transformation we deploy in various applications like cuisine) I suddenly remembered trying to make yogurt when I was myself very young (although not as young). So I had the idea – why not just make some!? Show as well as tell! What could be easier?
So the photomontage shows the steps, and the result:
First, sterilising (using boiling water) all the things we were going to use: the main container to go into the incubator (see below) for incubation, the measuring spoon, tongs, lid, measuring cup, and the pouring lip of the pan the milk will be heated in.
Second, warming a few cups of whole milk to 180 degrees (F). This will help remove various of the organisms that we *don’t* want to thrive in the incubation stage.
Third, cooling it down to about 110-115 degrees (F) with the aid of an ice bath. (Had to do this twice as I over-cooled the first time.)
Fourth, taking a few tablespoonfuls of live yogurt from a routine store-bought tub of plain. Mixing it with some of the milk, then adding it to the whole lot of milk and stirring it into the glass container.
Fifth. We needed to make an incubator where it could be left for at least 5 hours. The bacteria need a nice, still, warm environment to multiply and grow as they ferment the milk, turning it into yogurt. I decided upon a large lidded tupper-ware that was a bit larger than the glass container. I put the (open) glass milk+yogurt containing container inside. I filled the remaining outer space with hot water, covered the big tupper-ware with its lid, and then wrapped it all in some towels for insulation, and then put the whole thing into a microwave as a nice cosy enclosure, and shut the door. (Note: the microwave was not turned on!!)
Then we left the whole thing for 5 hours (actually maybe 5.5, but 5 is apparently the minimum), checked it (looked great!), left it for another 2 (it got a bit thicker), and then tasted it (thick and nice and tart-tasting!) and put it into the fridge.
Next morning: breakfast!
Best and tastiest science experiment for some time!