Refrigerator and Freezer Thermometers

[Shel_B]

I would like to get both a refrigerator and a freezer thermometer.  What brands and features should I look for?  Where in the refrigerator and the freezer should they be placed?  Thanks!

[dcarch]

I don't like freezer and refrigerator thermometers.

 

The inside environment of a home refrigerator is dynamic, there is no way you can get a good understanding of what is going on with temperatures in the freezer and refrigerator with thermometers.

 

1. Where are the food placed?

2. How often doors are opened.

3. When is the frost -free heater cycles on?

4. How much food?

5. How hot was the food when you put it in? 

 

Instead, a remote read IR non-contact thermometer ($30 to $300) is what I use. Just aim the laser beam at various spots, very quickly, you will get a very good idea the thermal characteristics of your entire refrigerator.

 

dcarch

[weinoo]

I would like to get both a refrigerator and a freezer thermometer.  What brands and features should I look for?  Where in the refrigerator and the freezer should they be placed?  Thanks!

How many features can there be on a thermometer?

[KennethT]

The problem with IR thermometers is that you have to calibrate the emissivity of each surface you measure. Otherwise, your readings could be off by 5 degrees F easily. Also, the temperature of the inside of the cavity (and the food, which is a thermal mass) could be very different from the wall temperature - especially depending on timing, like if the defroster just turned on.

I keep my refrig thermometer hanging on a middle rack in the middle of the box, away from the walls, but close to foods with a lot of mass (like a jug of water). I don't open the door very often, so when I do, I get a good idea of the ave temp.

In the freezer, it sits practically buried in a pile of food, away from the walls.

Just my .02

[dcarch]

The problem with IR thermometers is that you have to calibrate the emissivity of each surface you measure. Otherwise, your readings could be off by 5 degrees F easily. Also, the temperature of the inside of the cavity (and the food, which is a thermal mass) could be very different from the wall temperature - especially depending on timing, like if the defroster just turned on.

I keep my refrig thermometer hanging on a middle rack in the middle of the box, away from the walls, but close to foods with a lot of mass (like a jug of water). I don't open the door very often, so when I do, I get a good idea of the ave temp.

In the freezer, it sits practically buried in a pile of food, away from the walls.

Just my .02

 

You don't really have to calibrate all surfaces unless they are drastically different in reflective. I have found in this test, by using cooking oil in the freezer and water in the refrigerator, using a regular thermometer, the IR thermometer is very good by comparision (and of course quick). Using a thermometer measuring one single location, you can be off by 15F +-.

 

I am very particular about the freezer, because I need very cold temperature for sanitizing my cold smoked salmon.

 

dcarch

[KennethT]

Right - similar surfaces will read similarly - but, for instance, the refrigerator walls may read differently than a frozen pork loin, or a box of frozen pizza, etc.

I know this is OT, but for critical freezing, I use a small, non defrosting chest freezer. It consistently stays at -10F, and a bit colder at the very bottom.

[dcarch]

The best temperature testing device for the freezer is a box of ice cream. 

 

 

dcarch

[weinoo]

I keep my refrig thermometer hanging on a middle rack in the middle of the box, away from the walls, but close to foods with a lot of mass (like a jug of water). I don't open the door very often, so when I do, I get a good idea of the ave temp.

This is what I do.  I recall an article a couple of years ago about where the coldest parts of the fridge are - surprisingly, not where we expect them.

 

There was also something (maybe here by Fat Guy) about dairy spoilage in the fridge, and how it is majorly affected by how often the door is opened and closed.

[MelissaH]

We use a remote-read indoor/outdoor thermometer. The transmitter goes in the fridge or freezer, and sends its reading to the receiver, which lives in the kitchen. No need to even open the door to get the temperature inside.

 

I'd love to get something with a little bit of memory, so we can track at least the high and low (for instance, when we're out of town) but I suspect my geek side is showing now.

[Shel_B]

The best temperature testing device for the freezer is a box of ice cream. 

 

 

dcarch

 

I get your point, unfortunately I don't keep ice cream at home.  If I did, it would be gone in a heartbeat ...

[rotuts]

i had something like these some time ago:

 

 

http://www.amazon.com/TA20-Audio-Visual-Refrigerator-Freezer/dp/B000I62FQI/ref=pd_sbs_k_4?ie=UTF8&refRID=0K2J7A21H4VZRQ7TG9YY

 

 

it had two channels   one section cup for the freezer and one for the refrig.  stuck on the side of the refrig.

 

I enjoyed it, understanding that it might not be giving me 'accurate' info

 

dont know what happened to it

 

then I found this just now:

 

http://www.amazon.com/ACU_RITE-Refrigerator-Wireless-Thermometer-00986/dp/B004QJVU78/ref=pd_bxgy_k_img_y

 

way cooler.

 

again, .....

[andiesenji]

I have three or four of these - only using three now as my newer LG fridge/freezer has an integral digital thermometer/temp control.

 

These from Thermoworks are accurate and sturdy.  At least one has survived being knocked out of the fridge, grabbed by the dog, carried outside, where I had to retrieve it - washed it off, used an emery board to file down the places where dog teeth had dug little pits.  It is still working just fine in my cheese fridge - which is kept at a higher temp than the regular one. 

 

I've tried various thermometers and in my opinion you can't improve on the ones from Thermoworks.  You can also get the fridge/freezer ALARM thermometers if you need critical temp control. 

[FauxPas]

I have three or four of these - only using three now as my newer LG fridge/freezer has an integral digital thermometer/temp control.

 

I have an LG fridge with separate digital temp control for fridge and freezer also, but i have never tested to see how accurate the interior temps are compared to the settings. I suspect that you may have done so - if so, wondering how they matched up?

 

Or maybe I should get one of those little Thermoworks ones and find out!  :-)

 

Also, your dog story made me laugh, especially filing down the dog bite marks. 

Edited June 7, 2014 by FauxPas (log)

[dcarch]

I have an LG fridge with separate digital temp control for fridge and freezer also, but i have never tested to see how accurate the interior temps are compared to the settings. I suspect that you may have done so - if so, wondering how they matched up?

 

--------------

 

Still, the whole appliance has only one compressor to cool both compartments. Having two temp control helps, but not completely.

 

dcarch

[MelissaH]

Bumping this topic back up to ask an updated question: does anyone know of a freezer alarm/thermometer with some form of connectivity? If your house thermostat and garage door opener can talk to you through a smartphone app, why not a freezer monitor?

 

I'm thinking of a situation a friend experienced where, unbeknownst to her, the deep freeze was plugged into a switched outlet. The switch was inadvertently turned off, and it was a few days before she returned to the basement and discovered the problem. I'm also envisioning a situation where something happens and a freezer dies when we're not home to hear an alarm sounding, but we would get an alert from an app (or could log in and check every day, if we were worried).

 

Does such a gizmo exist, for a reasonable price?

[rotuts]

there is he penny on the frozen water trick Ive read about here somewhere

 

probably  "" A Dcarch ""

 

[Smithy]

I'd love to find that penny-on-the-ice trick rotuts mentions (it does sound dcarchish), but haven't found it yet.

How about this one? Bluetherm Duo from Thermaworks

Depends on one's definition of 'reasonable' price, of course.

[Anna N]

So Smithy. This is what we did at the cottage. Fill a paper cup with water and freeze it in the freezer. When we were ready to close up the cottage and go home we would put a penny on top of that frozen water. When we returned if the penny had sunk down into the ice we knew there had been a power failure and a thaw had occurred. We could then decide if we would throw everything out or not depending on how deep into the water to penny had sunk. That at least was the Theory.

[Anna N]

Wow I looked up the link because I'm very interested too. But I would need to know my freezer was full of Wagyu Beef before I would invest that much in a thermometer.

[Smithy]

So Smithy. This is what we did at the cottage. Fill a paper cup with water and freeze it in the freezer. When we were ready to close up the cottage and go home we would put a penny on top of that frozen water. When we returned if the penny had sunk down into the ice we knew there had been a power failure and a thaw had occurred. We could then decide if we would throw everything out or not depending on how deep into the water to penny had sunk. That at least was the Theory.

Forgive me for assuming it was a dcarch trick! I figured that when the penny dropped it would close a contact and trigger an alarm. ;-) At any rate, it's a neat trick.

[MelissaH]

The penny on the ice trick, as well as the ice cube in a ziplock bag trick, are fine and good if you're home to look in the freezer. But what I'm mainly concerned about is what happens if the freezer fails (separate from the power going out) and only the cat is home. The cat cannot check on a freezer. Bluetooth is also not so useful in this situation, even if we're only across town. (Never mind the possibility that the freezer goes just after we leave for a long weekend out!) It's one thing to learn that there *was* a problem with the freezer and everything in it is kaput. It's another thing entirely to catch the problem early, and be able to save everything in it with prompt action.

[Smithy]

Well, Bluetooth to your computer, to which you could log in remotely, would work. My "penny drops and closes a contact" idea was so that some alarm would be sent to the same computer, or better still to your phone. Both are pretty kludgy, though, and there should be something already marketed to do the same thing.

A few years ago we bought a home alarm system that plugs into the phone line and has wired sensors. If the temperature dropped below a set temperature the system started calling telephone numbers that we'd entered. The alarm could also be set for high temperature, moisture or power failure. It worked well for a few seasons, although we learned that it wouldn't work if the phone had been knocked off the hook. It lasted a couple of seasons and cost less than $50. That sounds like the kind of thing you're looking for, if it can be set for freezer-level temperatures. We got it at our local hardware store, but (sorry!) I've forgotten the brand.

[MelissaH]

Well, Bluetooth to your computer, to which you could log in remotely, would work. My "penny drops and closes a contact" idea was so that some alarm would be sent to the same computer, or better still to your phone. Both are pretty kludgy, though, and there should be something already marketed to do the same thing.

A few years ago we bought a home alarm system that plugs into the phone line and has wired sensors. If the temperature dropped below a set temperature the system started calling telephone numbers that we'd entered. The alarm could also be set for high temperature, moisture or power failure. It worked well for a few seasons, although we learned that it wouldn't work if the phone had been knocked off the hook. It lasted a couple of seasons and cost less than $50. That sounds like the kind of thing you're looking for, if it can be set for freezer-level temperatures. We got it at our local hardware store, but (sorry!) I've forgotten the brand.

Smithy, that would be wonderful, except that we haven't had a landline phone since we moved into this house in 2003. And I'm not willing to leave a computer on when I'm away on an extended trip. We'd need something with WiFi for the idea to be practical.

[palo]

I have a Frigidaire upright freezer only that has a digital temperature display. I've set the temperature to -10 F. I also vacuum seal pretty much everything into meal size portions so freezer burn isn't a concern. At the temperature I have set, I believe that temperature fluctuations are a non-issue as it's unlikely food temperatures will get above freezing as I have a 10 degree buffer. The unit also has a power loss alarm.

 

That temperature is good for most food storage but ice cream not so much

 

p

[KennethT]

Melissa, I don't know of anything "off the shelf" to do what you'd like, but if you had a little programming experience, you could do it with a Raspberry Pi. You can get a thermocouple card for it, and then using the Pi, create a temperature log where it can log the temp once per hour or whatever. This can be stored on the main memory or SD card. The Pi has an ethernet port, and you can run a web server that can display the log, or write a script that will send you an email if a checked temp falls below (or above in this case) a certain threshold.

Slightly complicated, but not impossible....