I love drinking hot tea in the afternoons. I’m sipping hot ginger tea right now as I type this blog post. I enjoy hot tea that is hot enough I have to slowly sip it or else I’ll burn my mouth, but not so hot that I scald my lips as I draw the first tiny bit of tea into my mouth. Guess how hot that is?
It’s about 180 degrees Fahrenheit.
I know that because I got a digital kitchen thermometer a little while ago, and instead of just boiling water at home, then waiting for the piping hot brew to cool enough to the point I can start sipping, I thought I’d take the temperature of perfectly hot water, then, next time, I’d insert the thermometer probe into the tea kettle and heat the kettle up to that perfect temperature, rather than waiting for the tea pot to whistle because it’s boiling inside.
My new kitchen thermometer is very precise; it measures in one-tenth of degree increments. I know my kitchen thermometer is accurate, too, because when I inserted the probe into a teapot full of boiling water, the temperature read 212 degrees, plus or minus a few tenths of a degree.
Suppose my thermometer wasn’t quite so accurate as it is. Suppose it read two degrees off, so when I put it into boiling water, it read either 210 degrees or 214 degrees, but never 212 degrees.
Would that matter?
It depends. It depends on the context in which I’m using the thermometer. In the context of bringing hot tea to a perfect temperature, being off +/- two degrees is immaterial. I think I’d find hot tea heated to 182 or 178 degrees to be perfectly acceptable. In fact, I’ve found that I can be happy with hot tea served between 175 and 185 degrees. So, having a thermometer that reads one, two, three, four or even five degrees off isn’t a problem for me, and I wouldn’t seek to replace it. It’s good enough for my intended purpose of heating hot water to a point where I don’t have to wait before I start sipping freshly brewed tea.
But is my thermometer accurate?
You might say it’s not — it reads two degrees off from what it should. But in another sense, is IS accurate because its errant readings are within my tolerance for error. My tolerance for error determines accuracy and inaccuracy.
If something fits my tolerance for error, it’s accurate. If it doesn’t, it’s inaccurate. My thermometer gives me great precision, but I don’t really care about the level of precision it offers me. I want accuracy, and my tolerance for error says that as long as I don’t burn my mouth when I sip my tea, and I also don’t feel like I’m sipping tepid tea, then my thermometer is doing it’s job — it’s accurate for its intended purpose.