These days, a digital thermometer is up there with a good knife on the list of indispensable kitchen tools, but you never hear anyone recommend their analogue predecessors. That’s too bad: old-school thermometers do the exact same job for a fraction of the price.
I own a digital thermometer that I use for meat and only meat because I’ve learned the hard way that steam upsets it. This makes sense: digital tools run on batteries, which generally don’t play well with water, vaporized or otherwise. Unfortunately, I measure the temperature of steaming-hot liquids more than just about anything else—warm water for bread dough, scalded milk for microwave pastry cream, Swiss meringues, custard pie fillings, things of that nature—which means my candy thermometer gets a lot of use. Sure, it’s a bit slower, and it doesn’t measure tenths of degrees, but I’d rather have a measurement I can trust than functionally meaningless precision. (If you think there’s a perceptible difference between a custard cooked to 85ºC and one cooked to 85.5ºC, well, there’s not. Sorry!) Plus, calibrating a dial thermometer is ridiculously easy: all you need is ice water and a wrench.
To show you what I mean, I will tell you the story of my first Swiss meringue. Because I’m not a total dingus, I used Stella Parks’ recipe, which instructs you to heat the egg whites and sugar in a water bath to 80ºC. I stirred that godforsaken bowl for an entire hour, checking the temperature frequently, but my digital thermometer politely declined to read 80ºC. As it turns out, the steam coming off both the water bath and the meringue was making it go haywire, alternating between taking way too long to read the temperature and randomly shutting off. I switched to my candy thermometer for the next batch and the rest is perfect, fluffy history.
Admittedly, my digital thermometer is an OXO piece of shit I bought for ten dollars in 2009, but the original battery is still kicking and it does what I ask of it. If I owned a Thermapen, I might feel differently. But when mine finally goes to the Big Watch Battery in The Sky, I’m still not shelling out for a Thermapen or even a cheaper knockoff; I’m gonna buy a five-dollar dial thermometer and feel great about it.