Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

> Normal fridges just let the temperature have a wider swing which is good enough for most needs.

These wide swings annoy me. You hear that you shouldn't let your fridge go above 4°C, because that's dangerous. And you obviously don't want your fridge to go below 0°C. But finding a setting where the hottest part of the fridge doesn't go above 4°C (or even 5°C or 6°C) during the hottest part of the cycle and the coldest part of the fridge doesn't go near 0°C during the coldest part of the cycle is really pretty difficult, in my experience.



Put a thermometer in a plastic bag (to keep it dry) in a jar of water in your fridge, you'll likely find the temperature of items inside the fridge much more stable than the air temperature.


The yogurts at the back of my fridge still freeze up.

There's going to be a temperature gradient in a typical fridge, if only because one side is getting opened every now and then, and the other is separated by all the products which are inside.

I suppose what they're trying to do here is even out that gradient without running the compressor.


The time it stays above 4C unless you're opening the door of your refrigerator all the fucking time is mostly negligible in terms of the difference it will make for bacterial growth.

The foodstuff itself is loaded with water, it won't have an excursion dangerously above 4C just because you opened the door and the air temperature raised a few degrees.

If you are really worried about it (you shouldn't), and you don't keep your refrigerator full, add a few water bottles for thermal mass.


Why should that be dangerous? I have never heard that.

I have always had my fridge at 8°C and never had something dangerous happen to me. I have never come across fridges that were way cooler, apart from fridges of friends in Canada and the US. What's the reasoning?


The recommendation I've always heard in the Netherlands is 7°C, it's more recent that I've been seeing 4°C on meat packaging in Germany (where I live now). I doubt anyone's fridge is consistently at or below 4° without freezing things constantly, so I've been assuming this is wishful thinking and/or ass-covering on the manufacturer's part and not what anybody actually does. Your 8°C is close enough that it probably makes little difference, though afaik this is an exponential curve (at 14°C it would last far less than half as long) so I'd not be surprised if things spoil a bit sooner than they otherwise would

Even if your products generally meet their "should be safe at least until" date (Mindesthaltbarkeitsdatum, idk if it's the same as "best before"), you might exceed that longevity more often than you do now and thus have less food waste by setting the fridge colder - if food waste is a thing you have in the first place (I'm the type of person that is hungry all the time, opens the fridge when hungry, and isn't super selective (among what I've bought anyway), so food I buy ~always gets eaten before it spoils, but then when I see food waste numbers, apparently that's not the case for everyone so I'm just throwing this out there)

Edit: trying to fact-check myself, I can't find any trustworthy source in Dutch saying your foodstuffs fridge should be more than 4°C. I measure new fridges when moving in and again at least once during the first summer to make sure they stay at or below 7°C when we had the door open a normal amount of times, so I know they're that (and not much cooler, to not freeze items or waste energy). So far, products meet their minimum shelf life date thingy and almost always exceed it. Strange. Maybe this recommendation I heard predates the internet (showing my age here), or maybe every page on the internet assumes that nobody actually measures it properly and so they recommend a value that's half of what's actually safe?


> I doubt anyone's fridge is consistently at or below 4° without freezing things constantly.

My refrigerator is typically between 3-4°C, never had any problems with things freezing.


Crazy, I'd think the fluctuations would be way too big. How long does it normally run for when it does a cooling cycle? Is that temperature throughout the fridge or only on certain shelves?

Ours (well, our landlord's) runs very consistently for 40 +/- 3 minutes, with just over 1h30min in between during normal use, or 1h54min if it was closed the whole time (like at night). The temperature of products, as measured with a cheap infrared thermometer that's probably off like 10%, varies between 2 and 7 degrees, but it's not very consistent between shelves (top seems warmer but then the very bottom one, that is only half deep, is as warm as the top again). The products I checked have all been in there for days; reflectivity may be part of the difference, not sure. I don't know what the air temperature difference is at the beginning and end of a cooling cycle though


It's closer to 2-3°C in the drawers at the bottom and 3-4°C at the shelves at the top. However, it's very consistent otherwise.

I can't tell you how long it runs for because the compressor is too quiet for me to hear, sorry. Maybe if I had an energy monitor on it. Sounds like a fun idea.


Thanks for that explanation!

The Mindesthaltbarkeitsdatum is the deadline to which the item may still be sold by the vendor, iirc.


You should buy a fridge with a fan in the cooling chamber. My Samsung fridge has a nice fan and associated ducting to circulate air and keep temperatures ~uniform.


I may consider that the next time I buy a fridge, but the reality is that this isn't something I care deeply enough about to buy a new fridge over.


Maybe you can retro a fan into your current fridge. Nice little project!


I think the 4C recommendation is an average. There is not magic in ~1% temperature difference from 3 to 6. Just slightly different rates. Which again slow, but do not stop when it is at low end compared to high.


If you buy something good like a Sub-Zero it will stay within 1 degree of the set point.


> you shouldn't let your fridge go above 4°C, because that's dangerous.

Dangerous how?


> You hear that you shouldn't let your fridge go above 4°C

Really? My fridge says 8°C, I think?


Between 3°C and 5°C is the recommended refrigeration temperature


https://www.which.co.uk/reviews/fridges/article/how-to-store...

Christ.

I also run my fridge at 8C, which I think was the default setting when I bought it.

Gonna go change that right now.


8 degrees or just 8 on the 1-10 scale that many of them use?

(I always remember the recommended fridge temperature as 40F, which avoids the confusion.)


I suspect it's that. Most inexpensive refrigerators don't have thermostats. Which seems insane; it cannot add that much to the price.

8C is a perfectly fine temperature for a wine fridge. And they usually have thermostats because a wine fridge is a luxury item. As opposed to keeping people from getting foodborne illness.


> Which seems insane; it cannot add that much to the price.

Be careful what you wish for.

When buying my current fridge, I specifically tried to go out of my way to avoid complexity, but the opening for my fridge is an odd size so my choices were limited. The only fridge I could buy that didn’t have a bunch of crap that’s was guaranteed to break (ice maker, water dispenser [seriously? aren’t most fridges right next to a faucet?], LCD-covered glass panel, etc) that also had a thermostat had a digitally-controlled thermostat. No knob or physical buttons, just a capacitive surface for temperature adjustment and some LCD screens showing the fridge and freezer set temps. (Not the actual measured temps, that would be too useful, just the set temps.)

In hindsight, I probably should’ve just gotten one with a regular dial, but I was a bit fixated on the “real” thermostat. So now I’ve got that to look forward to breaking in 4-5 years and figuring out where the hell to source a discontinued fridge LCD panel from.


> water dispenser [seriously? aren’t most fridges right next to a faucet?

Same reason you'd keep a container of filtered water in your fridge.


...why would I keep a container of filtered water in my fridge? My water comes out of the tap already filtered at my municipal water supplier?

Maybe if I was on a well I would need to filter my own water, but then I definitely wouldn’t trust that job to a fridge.


Many people prefer a cold glass of water compared to the cool to room-temperature water that comes out of the tap (Hence the refrigerator for cooling). Filtering at the individual level is typically done for flavor, because depending on where you live, while the water is probably safe to drink (assuming HN readership demographics), it may or may not be particularly pleasant. Even here in the Bay Area, where we have that sweet, sweet Hetch-Hetchy water, I know people who live in buildings with pipes bad enough that they filter their water.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: