A while ago I posted my recipe for making yogurt, in which I slavishly imitated Alton Brown’s stern admonition to not heat the milk past 170 degrees Fahrenheit.
Last week I made a bonehead mistake while making my regular batch of yogurt; I turned off the alarm on the probe thermometer, but forgot to turn off the heat on the milk. As a result, I ended up boiling my milk and cream mixture for about 15 minutes.
It turns out that this makes your yogurt a lot better.
It does this in two ways. First off, it denatures some of the proteins in the milk so you end up with a lot less whey to pour off. I suppose somewhere there is someone whose biggest thrill in life is drinkin’ a nice tall cool glass of whey, but that someone is not me. The texture of the yogurt when you boil the milk is more uniform, and less gelatinous.
Second, you can tell by taste that the milk has been boiled. The finished yogurt acquired a very subtle, but noticeable, panna cotta flavor.
I tried to convince myself that having yogurt that tasted a little like panna cotta was somehow a bad thing. I failed. It’s awesome.
So, less wastage, a nicer texture, and a more interesting taste. There is only one rational conclusion: when making yogurt, boil that milk, chowhounds!
Cool, I’ve made yogurt several times but I’ve never boiled the milk. I did always leave it “culturing” for much longer than you are supposed to, usually a full 24 hours. Apparently that makes it more sour and such but the sour yogurt flavor is the one I love!
On boiling the milk in yogurt making, Harold McGee writes, “Traditionally, the milk for yogurt was given a prolonged boiling to concentrate the proteins and give a firmer texture. Today, manufacturers can boost protein content by adding dry milk powder, but they still cook the milk for 30 minutes at 185 degF or at 195 degF for 10 minutes. These treatments improve the consistency of the yogurt by denaturing the whey protein lactoglobulin, whose otherwise unreactive molecules then participate by clustering on the surfaces of the casein particles. With the helpful interference of the lactoglobulins, the casein particles can only bond to each other at a few spots, and so gather not in clusters but in a fine matrix of chains that is much better at retaining liquid in its small interstices.” (McGee, _On Food and Cooking_, 2004)
Your fifteen-minute boil earned you a more concentrated yogurt base and a finer protein matrix. Also, McGee notes that “prolonged boiling encourages browning or Maillard reactions … and generates molecules that combine to give the flavor of butterscotch.” No wonder your yogurt was good.
I’m not sure what Alton gains with his low-temperature method. Maybe he likes his yogurt to taste more like fresh milk.
This sounds like a good way to get a yogurt closer to greek-style consistency. And the maillard reactions also sound like a good thing. Yet another reason for me to get a better saucepan.
I tried this, and instead of my its creamy lusciousness, my yogurt was peppered with what can only be described as papery films. It’s like the proteins all globbed together during the culturing to make hundreds of little skins.
I’m going to hazard a guess that I failed because I used skim milk, which will often react less pleasantly to heating than high-fat milks.
One thing you can do is peel the top skin off the yogurt while it cools. But the texture is definitely different; I like it. De gustibus and all that.