Wednesday, February 9, 2011

More about thermometers -- specifically when and how to use them

Dear readers,

Thank you so much for your thoughtful comments about meat thermometers.  I wanted to reply to all of you, but didn't want to bury the interesting bits in the comments, so I am writing another post.

First of all, I'd like to apologize for my laziness in the last post.  It was really silly of me to start discussing pros and cons of different thermometers without talking about the tasks people do with them.  Considering the fact that my last career was in the field of usability engineering, that's an unforgivable sin.  The only thing I have to say in my defense is that I've been a little distracted the last 2 weeks with a certain fantasy book series.  If I was 14 years old, I wouldn't be embarrassed to tell you the title.  But since those days are long gone, there is really no excuse for my juvenile behavior.  So, I will try to be good now and concentrate.

The task some of you have mentioned when praising probe thermometers was cooking a large prime-rib roast.  I can see how the probe can seem very attractive.  You don't need to constantly open the oven and check your meat.  The thermometer will tell you the exact moment when it's done.  Right?  Not exactly.  Here are some ideas to think about.

Opening the oven is not all that bad
Nothing terrible will happen to your meat if you open the oven and check up on it.  Even if you do it frequently.  You don't want to stick a thermometer in and wait 25 seconds to get a good reading while the oven is opened.  Quickly get the meat out and close the oven door.  Test the meat and then return it to the oven.  If anything, this slight cooling off period will result in a more evenly cooked meat.

You still need to have a rough idea of how long the roast will take
If you don't have any idea when the meat is getting close, how would you know when to put it in the oven to have it ready by the time your guests arrive?  Also, how would you know when to start the end game with your side dishes?  In real life, you are not just sitting there waiting for the beep from your thermometer.  You should probably know roughly when the meat will be ready and use the thermometer often in the last stages of roasting to get perfect doneness.  That's very hard to do for large pieces of meat, which brings me to the last point.

You don't need to cook a huge roast even when feeding lots of people
I never cook a prime rib roast bigger than 3 ribs.  If I am feeding a crowd, I cook several such roasts.  It's much easier to estimate when a little roast will be ready and it's much easier to stick it in a skillet in the end for a good crust.  Here is my general approach to cooking all meat.  Ideally, you should also do a dry-run before the big event to get a rough idea of timing.  If you underestimated how long it will take, your guests might have to wait another 10-15 minutes, not another hour.  There is no reason why regular digital thermometers wouldn't do a good job with a prime rib task even though they might require a bit more work on your part.

But let's talk about tasks that happen much more frequently, at least in my kitchen:
  • testing steaks 
  • testing duck breasts
  • testing pork chops
  • testing racks of lamb
  • testing chicken breasts and thighs
The common theme here is pieces of meat that are 1 inch in thickness or more.  Let's use a thick steak as an example.  It's very rare that I cook only one steak, and it's very rare that the other ones are exactly the same thickness, and it's very rare that I managed to stick a thermometer smack into the center of the steak on the first try.  What does all this mean?  It means that I need to be able to remove the thermometer easily and stick it into another piece of meat or into another spot on the same piece of meat.  That's where a remote probe thermometer can turn out to be a hindrance.  It gets hot in the oven and becomes very awkward to pull out and stick back in since you need to use oven mitts.  The wire attaching the probe to the thermometer causes some difficulties too since it often makes the thermometer fall down as the probe is yanked out of the meat.  Maybe I am just a very un-coordinated person, but I find regular thermometers to be a lots easier to deal with for this task.

Another task you guys mentioned was monitoring the temperature of water for cooking beans in the oven.  You got me there.  I've never tried it, so I can't say for sure how a probe thermometer would stack up against a regular one.  But I wonder how much good does it do to know the exact temperature of the liquid if you can't easily control it.  Ovens cycle on and off, so they can't give you such perfect control.  What I might do is bring a pot of beans to 185-195F on the stove top while monitoring it with a regular thermometer.  Then set it in 200F oven and hope for the best.

I was getting concerned about my bias against probe thermometers.  I thought maybe I just had a few bad experiences with them, so I decided to check what Cook's Illustrated had to say:
We tested 11 models-several by the same manufacturers-and not one was flawless. The ones that accurately measured temperature sported function buttons that were too slow or too hard to figure out. Others that were user-friendly were also unreliable. 
The best of the bunch (ThermoWorks Original Cooking Thermometer/Timer) was great when it worked but has probes that even its manufacturer admits are sometimes defective. Until a better meat probe comes on the market, we recommend this one with reservations. Check the probe's accuracy by boiling water and taking a reading before trying it with a roast. If the probe doesn't read very close to 212 degrees, ask for a replacement.
It seems to me that the probe thermometers give people a false sense of security.   If you love the results you are getting with them, that's great.  But if not, it might be worth looking at a regular thermometer rather than another probe type.


Anonymous said...

I'm the person who wrote about simmering beans. Actually I do bring it up to a simmer on the range(as you suggest) since conducted heat from the coils is much faster than convected & radiated heat in the oven. But I've found that due to the oven cycling you mention, an oven temp that sounds like it should work to keep the beans in the simmer range of 185-195 often doesn't. Also the amount of liquid in the pot affects the oven temp needed to keep the beans where I want them. I don't need to know the exact temp, just the range; too cool and they take forever, if they boil they break apart. So I use the cable thermometer to monitor the liquid, although I'm sure if you just check occasionally with a probe thermometer that would work fine too.

Helen said...

Ah -- beans... They are so cheap, so innocent looking, yet so difficult to cook well. They still give me trouble sometimes, but I think I finally found a way too deal with them. The first trick is soaking in generously salted water (Cook's illustrated idea). The second is cooking in salted water on very low heat and if possible using a wide dish.

Anonymous said...

Hey there,

I love your blog. The posts are always easy to follow and the recipes look great. I'm a Boston grad student who's just started my own beginner's cooking blog. I'd love it if you would check it out and link to it sometime if you like it. The posts aren't as advanced as your recipes, but I think they're pretty tasty none the less.