Cheese making has been much on my mind lately, but as my press is not yet cobbled together, proper cheese will have to wait. In the meantime, I’ve begun working up to my lofty goal of mature white cheddar by starting with yogurt.
On the way back home from my (nearly) daily trip to the library on Thursday I swung by the grocery store and exchanged last week’s well-rinsed glass jug for a fresh half gallon of local milk and selected a half pint of plain Greek yogurt. This was the nearly solid, super-tangy kind of stuff with all the all-star bacteria team: S. thermophilus, L. bulgaricus, L. acidophilus, Bifidobacterium, and L. casei.
I went above and beyond the Back to Basics (the Reader’s Digest classic) instructions, with canning successes and brewing failures in mind, by sterilizing all my jars, lids, rings, and equipment in boiling water while I heated the milk. The idea, as with brewing, is to kill all the bacteria you don’t want and give ideal conditions for the bacteria you do want.
I heated four cups (1 quart) of 2% milk in a double boiler with 3 tablespoons of powdered instant milk as a thickener. I heated it to 180ºF to kill the bad guys and then brought it back down to 105ºF (which, but the way, takes seemingly forever when it’s a hot July day, even when you have three fans on) and stirred in the 4 tablespoons of purchased Greek yogurt I was using as my starter culture. I poured the inoculated milk into my sterilized jars and packed them in our camping cooler with a hot water bottle and a few weeks’ worth of crumpled newspapers. ‘Back to Basics’ recommends that the yogurt be cultured at temperatures between 105º and 115ºF for best results (quickest setting with least amount of bitterness) but I couldn’t seem to get the temperature over 80ºF in the cooler. According to the instructions I was following I was supposed to have finished yogurt in three hours, but due to my low and fluctuating temperature it took me a lot longer than that. Six hours into the experiment, after dinner, dessert, and evening chores, there was still little sign of thickening in the jars. I refilled the hot water bottle (for the fourth time) with near-boiling water, repacked the cooler (with a towel in addition to the newspaper, for good measure) and went to bed.
When I cracked open the cooler the next morning after breakfast and tipped a jar on its side there was no sloshing. I tried not to get too excited – perhaps it had cultured too long and become some sort of stinky cheese. Not so! I popped the lid and took a whiff and it smelled just like the fancy store-bought yogurt I had used as my starter culture! I grabbed a spoon and took a mouthful. Tasted just like it, too! I threw both pints in the fridge, victorious. Next time I need yogurt I will repeat the process – but the starter culture will be four tablespoons of my own yogurt! Theoretically, this could be the last time I buy yogurt – it should work like sourdough, perpetuating itself practically forever. However, I have heard that it can eventually stop working and a new starter culture will need to be introduced. Still and all, I’ve saved a lot of money (a quart of the kind of specialty yogurt I used as my starter culture is $7.00 but a quart of my organic local milk is $1.00 after the bottle deposit return) and some packaging, too (which also would have cost me money to dispose of).
My yogurt tastes great (especially as shown above with a spoonful of homemade jam and a drizzle of honey) but it isn’t quite as thick as I like it and there was a lot of whey. I reread the instructions in ‘Back to Basics’ and it sounds like my problems were due to the slow culturing at low temperature. I can prevent it on the next go round by using more thickener (up to ¼ cup according to ‘Home Cheese Making’ by Ricki Carroll) and culturing at a higher temperature. ‘Home Cheese Making’ also states that it takes six, not three hours to culture at 116ºF.