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When a product says "refrigerate" or "freeze", the temperature they're asking you to keep it at is not a mystery -- most refrigerators and freezers maintain an expected temperature range.

But other products indicate "room temperature" or that they should be stored in a "cool, dry place". Are there actual temperature ranges associated with these set phrases?

I grew up in North America, in a household where we couldn't afford to overly heat the house in the winter, or cool it in the summer. "Room temperature" was, therefore, 50-55°F (10-12.7°C) in the winter, and 85-90°F (29-32°C) in the summer. My perception of "room" temperature is similarly skewed -- this isn't at all "normal" from a N. American perspective, where most of my peers like to keep their houses at around 77°F/25°C in the winter, and 67°F/19°C in the summer. But I remain confused, at least, from a culinary perspective of what exactly I'm being asked when a product indicates these set phrases.

As a concrete example: I recently bought a tub of ghee. It indicates to me on the labelling that it does not require refrigeration, can be kept at "room temperature", and should be stored in a "cool, dry place". My apartment is 80°F/26.6°C right now -- is this "room temperature"? (It'll cool to ~61°F/16°C overnight.) In the meantime, it's significantly warmer than the store shelf I bought it from, and the ghee has gone from a soft solid to pure liquid. This change of state (solid -> liquid) is what prompted my concern that I'm misinterpreting "room temperature" in terms of food temperature and safety.

Roddy of the Frozen Peas
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    Another fat that's definitely storable long term without refrigeration but solidifies in a cold enough room is olive oil. Slightly cooler than for ghee, but I'm mean enough with the heating and unbothered enough by the cold to see it. My kitchen normally only gets cold enough for it to go cloudy and thick (though there have been exceptions) but I don't take it in the camper van in winter in case I can't get it out of the bottle. – Chris H Sep 07 '22 at 06:03
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    I suspect though, that this difference is less important for food safety than for some cooking steps that rely on the behaviour of fats at different temperatures (like you'd soften butter before creaming with sugar) or in baking when yeast works much more slowly colder – Chris H Sep 07 '22 at 06:05
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    I'd always refrigerate ghee, whatever it says on the packaging. It *will* go rancid in fluctuating temperatures, long before its 'best before' date. – Tetsujin Sep 07 '22 at 08:11
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    Up until about 2019, the "kilogram" was based on a real, physical object housed in Paris. Now I'm imagining an official "room" from where all "room temperature" is based off of. – BruceWayne Sep 07 '22 at 14:22
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    @BruceWayne: behold [the room temperature room](https://www.youtube.com/watch?v=VxxYqE4Gil8)! – Stephan Kolassa Sep 07 '22 at 14:46
  • I think this is a tricky issue because even though many regions of India didn’t have air conditioning and gets warmer than where I live, I likely don’t go through ghee as fast as they do, so things like container size and how long it’s been sitting at the store might be factors – Joe Sep 07 '22 at 15:40
  • @Joe - before it's opened it's pretty much sterile. Best before date is just that, *best* before, not inedible after. As soon as you open it, the clock starts ticking. btw, *most* of the world doesn't have aircon. – Tetsujin Sep 07 '22 at 15:48
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    "Cool, dry place" is a remnant of when houses had root cellars. Even then, though, lots of regions didn't have root cellars, and of course apartments have never had them either. – RonJohn Sep 08 '22 at 02:28
  • Don't people just make their own ghee as needed? – Dennis Williamson Sep 08 '22 at 22:14
  • I'm lazy and also am really bad at clarifying butter. It's also just an example. You can mentally substitute "honey" which has similar storage instructions (and similar observable state changes, liquid -> solid.) – Roddy of the Frozen Peas Sep 08 '22 at 23:02
  • @RoddyoftheFrozenPeas Honey would be more sensitive to storage conditions than ghee - it's a supersaturated sugar solution that's nice and stable when ratios are balanced, but add moisture and that balance is thrown off, it crystallizes, has even more available water for microbial activity, and may begin to ferment -http://dx.doi.org/10.1016/j.foodcont.2004.09.003 – borkymcfood Sep 09 '22 at 04:15
  • 25 degrees sounds just incredibly stuffy to me? Are people really heating their houses that high? Why do they heat to a higher temperature than they cool in sumner? – Tim Sep 10 '22 at 08:34

3 Answers3

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"Room temperature" as used for testing, analysis, and validation purposes generally falls within the range of 65F-75F (18C-24C). Published research will typically specify temperature ranges used.

Both the FDA Food Code (2017) and Canadian Food Retail and Food Services Code (2016), providing guidelines for inspection activities, take an outcome-based approach and do not reference specific storage temperatures or humidity levels as products stored unopened in these conditions are designed to be safe or are self-evident if spoiled/unsafe - mouldy potatoes, rusted or swollen cans, etc.

In most jurisdictions in North America, refrigerator and freezer temperature conditions are often codified in laws and may be required to be explicitly labelled for consumer protection since pathogen activity is not as readily evident as spoilage - some Listeria, for example, can reproduce in food below 40F/4C, making both maximum storage temperature and duration needed.

A better source for optimum room temperature conditions would be your local building code, though most will specify the same range noted above and humidity <60%. If it's comfortable for humans, it's most likely suitable for products designed for those conditions.

For your ghee example - it originates in India for preserving butterfat at 30C+ temperatures and seasonal relative humidity close to 100%. When properly stored in an airtight container there is no water available for microorganism activity, and the concern is more for long-term quality decline due to oxidative rancidity.

borkymcfood
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    Do you have any source for your first claim? I work in the electronic industry, and room temperature is most definitely 25˚C. – Vladimir Cravero Sep 07 '22 at 12:57
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    @VladimirCravero there is no reason for "room temperature" as defined for electronics to be the same as defined for food. – rumtscho Sep 07 '22 at 14:58
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    @VladimirCravero I think "room temperature" gets used for SATP (Standard Ambient Temperature and Pressure) in some STEM professions, which is indeed 25°C, but other definitions depend on local usage; for example, [United States Pharmacopeia indicates "controlled room temperature" as 20-25C°C, European Pharmacopeia 15-25°C, Japanese Pharmacopeia 1-30°C (though "ordinary temperature" is 15-25°C)](https://en.wikipedia.org/wiki/Room_temperature#Definitions_in_science_and_industry). – Daevin Sep 07 '22 at 15:02
  • @VladimirCravero as others noted above, these room temperature ranges are applicable to food and food safety, and in North America these temperatures are representative for ideal conditions with normal fluctuations. A specific scenario is Health Canada's sanitizer efficacy validation, using 18C-25C - https://www.canada.ca/content/dam/hc-sc/documents/services/drugs-health-products/drug-products/applications-submissions/guidance-documents/disinfectants/disinfectant-drugs/disinfectant-drug-eng.pdf - p.13 – borkymcfood Sep 07 '22 at 16:12
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    @VladimirCravero and even more relevant to the average food premises operator, many (not all) sanitizer test kits specify testing at room temperature for accuracy - Hydrion's QT10/QT40 products explicitly state 65F-75F. – borkymcfood Sep 07 '22 at 16:17
  • Thanks for your replies - I was just curious about this topic as, apart from electronics, 25 degC is pretty common across the board. To explain why my brain made the connection, I am in the silicon industry and my day to day job is precisely "testing, analysis and validation"... of silicon chips :) hence the dissonance for me in reading 24 degC next to it. – Vladimir Cravero Sep 07 '22 at 21:34
  • @VladimirCravero that's **really warm**!!! In my air conditioned North American experience, 70-72˚F (21-22˚C) is the nominal "room temperature". – RonJohn Sep 08 '22 at 02:23
  • @VladimirCravero yeah, given that you said "electronic industry" I assumed you were relating with the SATP standard for "room temperature", that's why I called that out specifically (which, as a former chemist, I also usually associate it to :P). – Daevin Sep 08 '22 at 18:28
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It depends on whether you are talking about food safety, or food quality.

When you are talking about food safety, then "room temperature" is the complete range between 4°C (40°F) and 60°C (140°F). There are upper limits for the time that refrigeration-needing items can spend in this range (anywhere in it). "Cool, dry place" is not defined from the point of view of food safety.

When it comes to food quality, there is no strict definition. There are optimal conditions hiding behind each of these terms, and the farther you go from them, the quicker your food will deteriorate, in noticeable ways like mold, or unnoticeable like the slow loss of aroma in spices. So, it is not a range, it is more of a target with a lot of leeway.

For the target temperature, I would say that it is about 22°C (70°F) for "room temperature" and 15°C (60°F) for "cool, dry place". I don't have references for this, but it is quite compatible with both the conditions at which many foods do well, and with the actually available conditions in many households in the western world (although this is changing - many modern households no longer have a 15°C (60°F) cellar or pantry).

Xander Henderson
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rumtscho
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    The ideal room T° according to [this commercial document](https://vasco.eu/en-gb/blog/ventilation/ideal-temperature-and-humidity-office) is exactly 23°C (73.4°F), but back when I was working in the pharmaceutical industry, [it was defined as 10°C-30°C](https://ispe.org/pharmaceutical-engineering/september-october-2021/temperature-humidity-requirements-pharmaceutical) (30°F-86°F) for the companies I worked for... – Fabby Sep 07 '22 at 14:50
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    @Fabby these sources are interesting, but neither of them are about food storage. So there is not a perfect overlap with the culinary sense of the term (nor would would it be expected). – rumtscho Sep 07 '22 at 14:56
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    That's why it's a comment and not an answer... @rumtscho – Fabby Sep 07 '22 at 14:58
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    Rumtscho, please don't put me in a room at 60°C! I'll be nice! – Dawood ibn Kareem Sep 07 '22 at 21:57
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    @DawoodibnKareem: 60°C? That's kind of chilly for a sauna, can you please turn up the heat a bit? :D (But seriously, humidity and physical activity make a huge difference. Try doing heavy physical exercise at 60°C and 100% RH and you'll pass out in minutes and probably die if not rescued. Sit naked in a dry room at 60°C and you're probably fine indefinitely, as long as you have enough water and electrolytes to drink to replace what you're sweating out.) – Ilmari Karonen Sep 09 '22 at 08:36
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If you are reading this in a recipe, as opposed to product packaging, then "room temperature" and "cool" are going to vary according to the writer. That is, those terms mean different things for a Finnish recipe author than they do for a Brazilian one.

As a specific example where this could affect cooking is making dosa batter. Indian recipes often tell you to ferment it at room temperature, but the temperature they mean is 26-30C. If you try to ferment it at American room temperature of 21C, the batter will not ferment properly or will take days instead of hours.

Conversely, on pizza forums I've handled questions from Indians who had problems making pizza dough because room temperature ferments were too warm and the dough overproofed.

So, to answer your question: They do not mean a specific temperature if found in a recipe.

FuzzyChef
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