The electronics that makes a digital thermometer work is not very complex. Basically a voltage stabilizer to maintain constant battery voltage as the power is slowly used up and voltage drops. There is a temperature compensation circuit to automatically adjust operating lineal response whether your room temperature is very low or very high. The sensor, typically a thermocouple, which provides the measurement, is read against an internal reference to give you the readout. The entire package is inexpensive electronics (less than $10.00) which gives you response time in milliseconds. Why some thermometer reads faster than the other? The response time is highly dependent on how small they can make the thermocouple sensor /probe. The smaller it is the shorter the response time. The problem of making it too small is breakage and difficulty in manufacturing. They need to have the metal casing to be very strong so that when you push the probe into the meat it will not break too easily. When you push the probe into food, the metal probe travels thru different temperature zones, typically from high (212F) to low, and the metal will carry the heat from high temperature to low temperature and heats up the food in the low temperature zone. It will take time for the temperature to reach equilibrium, depends on the weight (mass) of the probe. dcarch

Okay Carol and others, I checked the website for the Thermopen thermometers and they also have one that is probably in line for what I would use it for and I think it's about $17 or so. I think I'll forego the King Arthur's and opt for it. I don't think of an instant read as a meat thermometer but one for many uses. If I did as much as some of you do with preserving, putting up or whatever you choose to call it, I would get the "Daddy of them all" in a heartbeat. Jude

Thermapen is worth every penny. You can use it on meat, baked goods, whatever. It really reads in under three seconds. It was really hard for me not to order one of the splash-proof ones to replace my "ancient" one when I was buying them as Holiday gifts. Most "instant" read thermometers on the market don't cut it. 6-10 seconds isn't instant. I want to open the oven/grill - go in to two or three places, and get out. The CDN quick-read units are pretty good as well; 5 or 6 seconds, for about $20 for the DTQ450X -- look for the ones that have the "turned down" (smaller diameter) tips for the last 1/2" or so. Whole Foods sometimes has these, and I see them at Amazon as well. Mechanical dial thermometers don't ever fall in the "instant" category for me. (Baked goods will often hold at below 200 until done, then shoot up when the moisture starts leaving as steam.)

Having surfed the Thermoworks site for a while, I’m now changing my plans. We had to take out the roast so many times. Plus, with the new oven it is not as high top to bottom or as deep front to back. We had to put the roasting pan in the oven in a direction that meant we could not read the leave-in meat thermometer without pulling the roasting pan out. Considering our $ 40 roast did not turn out, even though I don’t roast meats often, maybe looking for a cheap instant read is not where I should be going. Now I’m leaning toward a thermometer with a probe. (lascatx, I had typed this reply before seeing yours above! Computer froze and I had to come back to it. ESP) Plus, a few days before Christmas when making cheese, a probe model could have spared me the lengthy wait for a couple of quarts of cream to come to 190F on the stove, standing over it, without constantly having to dip my candy thermometer in. Plus when I make yogurt. Between the Thermoworks “DOT” and the Chef Alarm, which would you recommend? Thanks again.