Resurrecting the California Cooler

Picture of Resurrecting the California Cooler
Coastal Northern California is blessed with a very moderate climate, generally on the cool side, especially at night. Before the refrigerator became common in households, denizens of this region took advantage of the cool weather by storing perishable foods in a special kitchen cabinet that brought in air from the outside -  the "California Cooler."

When the refrigerator came along, it seems that, over time, the vents were boarded up and the California Cooler was all but forgotten. Today, if you walk the streets of my hometown, Berkeley, where most of the houses were built in the 1920's, you will see many homes, and even apartment buildings, with the exterior vestiges of these vents.

My house is such a house. When we decided to remodel our kitchen in early 2009, I came up with the idea of opening the vents and bringing our California Cooler back to life. What better way to conserve energy in this age of green thinking than to keep foods cool with outside air? This is the story of the resurrection of a California Cooler.
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Step 1: History of the California Cooler

Most of the information I have found on the Web about California Coolers consists of blogs dealing with kitchen remodeling.. This blog ( has some interesting information. The author says that the California Cooler came into existence in 1910, not in the 19th century as I would have thought. I may have to go to the library to find out more about the history. Below are a few more interesting links that I've found.

In this link someone is remodeling their kitchen and debating whether or not to keep the CA Cooler

Below is a gallery of California Cooler photos that I shot in South and West Berkeley, actually photos of the exterior vents which, presumably, are all boarded up. They are VERY common around here and the majority of them seem to be floor-to-ceiling pantries. Our single, large vent seems to be very unusual.

scaffnet3 years ago
OMG - just read this:

"I have started doing little things to make our fridge not work as hard. For example, when I cook a big pot of soup, I let it cool down to room temperature until putting it in the fridge. Sometimes I'll leave something out overnight (if it doesn't have a smell that would attract animals) and then put it in the fridge in the morning, shaving off the amount of cooling the fridge needs to do on that item."

You understand you are playing Russian roulette with microbes by doing this right? You may end up making your fridge work less but your guts work more to expel food that has spoiled.

Food is at high risk for spoilage if it is held at temperatures between 40 and 140F for longer than 2 hours.
Absolutely Correct!!

I am certified in the state of Connecticut as a licensed Food Handler, and what ravenwing is doing is creating the textbook perfect conditions for the creation and propagation of C. Botulinus, and Salmonella, as well. This practice is extremely hazardous!! One airborne spore, allowed to enter this food medium at temperatures between 40 degrees and 160 degrees Fahrenheit, and then sealed anaerobically, will kill your entire family, if it doesn't blind them first. If you doubt what I say, I suggest you use your little computer to research the local Public Health website in the town you live in. And she can tell every restaurant she ever worked in that the management is literally endangering the lives of every customer! That is, if you believe her claim, which I certainly do not. This is not a joke, this is a very serious, life- and death- matter!!
rpb Pilgrimm3 years ago
There is also a big danger of heating up EVERYTHING in your fridge if you put pots of uncooled items in there, which risks spoiling ALL OF YOUR FOOD, so given the choice I generally let foods cool outside the fridge and put them in when fairly cool.

And it's not like the hot thing you are putting straight into the fridge is going to cool to 5C immediately anyway (while it's heating everything else up!).
Pilgrimm rpb3 years ago
In order to prevent "heating up" the entire contents of the fridge, restaurants, caterers etc., often sit a large pot of hot food in an ice bath, stirring frequently, to reduce the temperature quickly, and maintain food safety. You can find large polyethylene "coolers" in restaurant supply catalogs which are sort of like a large jar with a round bottom, not intended to be free-standing, but for suspension in a large stock pot full of hot soup. The "cooler" has a screw-top, and is filled with ice, and then dropped into the pot, cooling it rapidly! If godforbid the ice should melt, replace it with some more!

Too many people in here putting absolutely one point of view ahead of modern, common practice. One lady wants to kill her family, and another fella says its her right to do so..... Try thinking a bit before engaging tongue, and allow for a different, maybe even safer method!
rpb Pilgrimm3 years ago
> Too many people in here putting absolutely one point
> of view ahead of modern, common practice.

That's your one point of view...! And that might also make sense if this were a discussion amongst restaurateurs, but this is instructables, and most people commenting here are home owners doing home cooking.

None of us will have "ice bath cooling apparatus", and it is unreasonable to expect any of us to have such things. They are also unnecessary for home cooking.

I admit that sometimes, for speed, I will put a very large pot of fresh soup in a sink of cold water to cool it down more quickly before putting it in the fridge, but apart from that there is no particular danger from allowing recently-boiled soup to cool, covered, for a few hours before putting it into the fridge.

In addition, since we are home cookers with domestic refrigerators, it is not safe to put hot items into a domestic fridge because it WILL heat up other neighbouring items for some time, some of which may have been in the fridge for a while, and some of which may get heated up several times, each night, when hot items get placed into the fridge.

Let the fridge do its job - keeping cool things cool. Just be sensible with the rest - let food cool before you refrigerate it. And if it will cool slowly (large pots or very hot weather) or may already have a short shelf-life (items not recently boiled) then try to cool it quickly, refrigerate it promptly, and then keep track of how long things have been in your fridge!
Pilgrimm rpb3 years ago
"In every restaurant I worked in, cooked food was ALWAYS cooled to room temp. before refrigerating it."

"so the restaurants are required to break the surface of the soup and stir in possible pathogens during the cooling process... remember there is a human breathing right above that soup while it is being stirred... "

"Refrigeration was a massive improvement in public health safety. Before mechanical refrigeration they use to haul enormous blocks of ice down from the Northern America and kept it insulated with straw. In the old UK structures (as in the middle ages) they had ice lockers."

"It is slowly being discovered that our very aversion to germs and our futile fight to eradicate them from every aspect of our lives is also robbing us of our natural ability to fight off many of these germs. Our immune systems actually become stronger only with contact with various germs and our dependencies on antibiotics only leaves us less able to defend against germs and stronger and more virulent strains"

I don't really disagree with anything being said here, on an individual basis. Treat your food anyway you wish. I can refuse to eat it if I wish. When ravenwing made the first quote above, it started getting a bit scary. Botilinus toxin DOES exist, it IS FATAL, even Al-Qaeda knows that. Ravenwing never saw the owners of every restaurant she ever worked in follow poor food-handling procedure. The majority followed safe procedure, she just wasn't paying attention, I'm sure!

In closing, (I hope...) The chances of poisoning yourself or a whole congregation are relatively small. But there were a few people making some VERY broad statements I thought it important to refute. The long & short of it is, do what you want. Don't bother me if you get a bellyache!

dlginstructables (author)  scaffnet3 years ago
I appreciate your comment, but I think this is a debatable point. To my knowledge, I have not had food poisoning or any problems with spoiled food. I think in general people overdo it with refrigeration. When you say food is at risk for spoilage between 40 and 140 F for longer than 2 hours, that can't possibly be true as a general statement. Think about it - people bring sandwiches to work for lunch all the time and have them at room temperature for several hours. Each food needs to be treated on a case by case basis and by challenging our notions about refrigeration, we can use a little less energy for that purpose. Eggs are one of the best examples. Everyone keeps eggs in the fridge and my experience says that they do just fine at California Cooler temperatures for long periods of time.
It is not debatable, it's science.

Plenty of foods provide a perfect habitat for the growth of microbes between 40 and 140F.

Below 40 and growth is slowed or halted. Above 140 they can't survive - although some newer strains of e. coli have been shown to be very heat and pressure tolerant, which is cause for concern.

"There are two completely different families of bacteria: pathogenic bacteria, the kind that cause food borne illness, and spoilage bacteria, the kind of bacteria that cause foods to deteriorate and develop unpleasant odors, tastes, and textures.

Pathogenic bacteria can grow rapidly in the "Danger Zone," the temperature range between 40 and 140 °F, but they do not generally affect the taste, smell, or appearance of a food. In other words, one cannot tell that a pathogen is present. "

When you are dealing with dairy, meat and beans it is entirely foolish to disregard safe storage temperatures, whether the food is raw or cooked.

For example, restaurants are required to take soups down to below 40 as quickly as possible before storing it in their coolers. They do this by putting the pot in a sink full of ice and water and stirring the soup until it is cool.

I'm a serious home canner. I have a root cellar. And I have been in the restaurant business for years. So I understand there are plenty of foods that don't need refrigeration.

However, "challenging our notions about refrigeration" is not sound advice, especially when you are coming at it from energy use biases, which have nothing to do with food safety.
I'm a serious biologist. I have a lab, where I grow bacteria for a living. And I sez that advice like this is why our society is over-sanitized. In order for pathogens to grow in food, they have to show up in the first place. In the case of a pot of soup, if it's covered while hot that won't happen. In the case of eggs, they are already sterile little globes that do a really good job of keeping pathogens out, because that what the growing embryo needs. The restaurant business has plenty of rules that should never apply to home kitchens (are your sponges soaking in a tub of disinfectant at your house?). And canning is the process of rendering something sterile so that it can be kept totally unrefrigerated for months at a time. For perishables that will be eaten within days, there are many fewer issues.

I love this idea! If I owned instead of rented, I'd be doing it now. As it is, my kitchen and pantry are unheated, and we keep lots of food out of the fridge. It's great! Great job, dlg!
You can do whatever you want with your own food. I'm certainly not a zealot about cleanliness and procedures in my personal kitchen.

But to suggest that the growth of pathogens in food is "debatable" is borderline irresponsible.

And for a "serious biologist" to suggest that a covered pot of soup is an acceptable safeguard against pathogens is downright laughable.

Here's a scenario for you. You make the soup. You cover it and put it on your counter to cool (which in itself is a bad idea, as you are now keeping it in the danger zone even longer by trapping in all that heat with the lid).

A family member takes some some with a ladle and puts the ladle on the counter, where it picks up some critters. You come back in later to stir the soup with the same ladle, which inoculates your perfect growth environment (AKA "soup") with said critters.

Maybe some bad critters will grow. Maybe something unpleasant will happen when you eat the soup, maybe not. But why take the risk? Is your bathroom that awesome a place to hang out?
I'd hate to be one of your children.
I am reading this and cannot help to think back at some things I have seen over the years.

In 1989 I saw people selling meat in Namibia. A whole carcass, in the sun, at about 38 degrees Celsius. That is really hot. It took then 4 days to sell everything. When they grab hold of the carcass to cut a piece of, the area around it turns black because of the flies that were sitting on the meat.

I did not buy any of that meat for obvious reasons, but it sure goes a long way in proving that modern day thinking in terms of germs and sterile environments might be a bit over the top.

I do not say that we should leave meat out in the open, but I do think we can leave more things unrefrigerated.
keng scaffnet3 years ago
I think that America (for some reason though I probably lean more towards bad law-makers and good (that is deceitful) lobbyists) has had some things beaten into us rather than proven to us. If you take a look around aka Germany, New Zealand, and Britain, eggs are kept at room temperature in the stores where they are stacked in an isle and sold.

I think we need to rethink our 'danger' zones and food handling methodologies. I think some maybe over regulated in order to get people to at least comply with a lessor standard that wasn't being adhered to before the more restrictive regs were put in place.
Calorie keng3 years ago
Most of the countries you mentioned have very cool clients. I lived in various parts of the UK, and some people did put their eggs on the shelf. But the interior of our house was kept at 60F or so. Student poverty and such...

Refrigeration was a massive improvement in public health safety. Before mechanical refrigeration they use to haul enormous blocks of ice down from the Northern America and kept it insulated with straw. In the old UK structures (as in the middle ages) they had ice lockers.

I have no idea as to why someone would take a chance with something that is so elementally obvious.

Food Refrigeration is ubiquitous for a reason. It allows for food to be kept safer and cheaper than non-mechanical designs. Cheap and safe. Like seatbelts. It only takes one time. The odds of being in a car accident in a lifetime are pretty good, particularly in New Zealand.

It only takes one time for something to go seriously wrong. Bohemianism is not a fun way to die. The mechanism of death is basically the same used in various chemical weapons.

I see... so the restaurants are required to break the surface of the soup and stir in possible pathogens during the cooling process... remember there is a human breathing right above that soup while it is being stirred... If that actually *is* a regulation, then I really must challenge it's efficacy.

It is slowly being discovered that our very aversion to germs and our futile fight to eradicate them from every aspect of our lives is also robbing us of our natural ability to fight off many of these germs. Our immune systems actually become stronger only with contact with various germs and our dependencies on antibiotics only leaves us less able to defend against germs and stronger and more virulent strains.
I like the cut of your jib sir.
I keep my eggs in the cupboard. I thought everyone did..

Love the idea, no houses i know in New Zealand ever had these coolers though, and I'm not about to knock a hole in my rented property :D
I've seen a few of them in various rental properties in NZ. My father calls them a meat safe, like those camping food-storage things you hang from trees.

I've always found those egg-holder things in the doors of fridges to be uselessly small; the eggs always fall out when you open the fridge. I've kept my eggs on the bench for years. Um. Not the same eggs the whole time, obviously. But they each last a month or so quite happily.
Tizme JermsG3 years ago
Safes were commonly installed in homes in NZ in the past and were still fitted in The State houses right up through the '50s (Kawerau, Meremere, etc). Early ones were a wall mounted cupboard as previously described. The later ones had a "fly screen wire" covered vent through the floor at the bottom of a set of 3 vertical cupboards with the shelves in each made of 3'x3/4" slats with gaps.Another vent either to the outside or the roof space ensured air flow. They were used for fresh vegetable storage(and eggs). Most homes had refrigerators too. As a country kid in the 40's my mum also had a meat safe hanging out in the cooler 'tank shed' but the meat was never in there for long. However Dad was a keen deer stalker and I remember a hind quarter often hanging out there too. A chunk of meat was sliced off and the rest left there in a muslin bag (to keep flys away). He is now in his 90's so maybe we had tougher guts in those days.

A few comments to fuel this fire. First, if the food is cooked (ie. soup) above 140F and the lid left on for that time, the microbes (ignoring heat resistant strains) are all dead. If that container is left closed before cooling into the "danger zone", the inner contents should be sanitized (not sterilized) well enough to cool outside prior to refrigeration. Second, being outside means that there is better airflow around the the container to provide quicker cooling than just sticking the item in the fridge (what most people do rather than water bath it while stiring) where there is little to no airflow unless you have an industrial fridge with an air circulating fan that runs all the time. Third, "danger zone" and all this other guide lines are overprotective by nature since there is a difference between leaving a pre-boiled pot of veggie soup covered and outside in 45F temps for a couple hours and leaving an open container of mayonaise out on your counter on a humid 80F day. All the guide lines are meant to be a suggestion for best chance of never getting a food spoilage illness. By the way, i'm a home brewer. I take a sugar rich substance and leave it at about 65-70F (sweet spot of the "danger zone" for yeast) for 6-12 hours before the yeast take hold and provide a carbon dioxide layer on the wort protecting it. Which goes back to my first point of sanitizing the contents and container and keeping a closed system.
OMG!! How did our ancestors ever survive all those centuries without a refrigerator to preserve their food...

While it is true that there are "optimum" temperatures to reduce risk factors, there is a difference between observing due caution and outright fear-mongering. There is also quite a bit of difference between the regulations for a restaurant that serves hundreds of people a day and a private residence. Make sure you understand these differences before making blanket statements condemning a private party under commercial regulations.

Then there is the further fact that most refrigerators operate between 35 and 41 degrees Fahrenheit... interesting that the high end temperature of a "normal" fridge is within the very spec that you claim is so very hazardous.
In every restaurant I worked in, cooked food was ALWAYS cooled to room temp. before refrigerating it. They were very large pots and pans and took quite some time to cool. The only exception to this was if it was closing, food was put into the cooler before locking up.
hackbyte22 days ago

Heh, i live in a bigger concrete building (8 levels) build in the 1960ies .... we even had this type of cooler in our kitchens ..... but a few years ago, the landlord has equipped our entire block with thermal insulation on the outside so now all vents are permanently covered and so closed an unusable ;(

Ehm btw, sorry ... i forgot to mention that i live in Hamburg, Germany. ;)

adelwyn8 months ago
I'd love to see the California Coolers back in existence. These were actually used in Southern California even earlier than 1910. I work at the Marston House in Balboa Park, San Diego ( It was built in 1905 by Irving Gill, and it has a pantry room that is a walk-in California Cooler. It is so well built it can be 20 degrees cooler inside than the surrounding house. Gill added a curved metal vent that catches ocean breezes. I hear there is one in the Gamble House in Pasadena as well (Green and Green, 1908:
mycsip1 year ago
I like the idea of the cc. I eat fermented most everything. From home made bubbling salsa to raw milk with no refrigeration for 6 years. I don't fridge my eggs. My raw cream smells like the strongest yogurt. I haven't drank pasteurized homogenized milk in years. All health starts in the gut and if fermented foods aren't eaten the gut is not healthy. All cultures (!) use or used at one time cultured foods. Sauerkraut, kimchee, miso, tempeh, etc. Gingerale, rootbeer, mustard, and ketchup were all fermented foods at one time. Tofu originally was made with fermented soymilk. We have more bacteria then cells in our body. We are basically formed of bacteria. there are more neurotransmitters in the gut then in the brain. The GAPS diet explains this very clearly. Pasteur even admitted he was wrong about bacteria being 'germs.'
nanalaura1 year ago
I was fortunate to see a fully restored "California Cooler" in a beautiful Craftsman home in Sacramento, Ca. The cool air is drawn from the lower vent, warm air released through the upper vent.
The owner uses the cooler for what would have been cellar items: potatoes, apples, carrots, etc. and says it is excellent for storing bananas!
You people who are saying that you can keep out microbes by just leaving the lid on a hot pot and letting it cool to room temperature are darned right wrong. The only way that this would be true is if the lid to the pot was air-tight, and I will explain why:

Say you just cooked a big pot of soup and you turned off the stove, the lid is on, and it's an ideal condition where the contents are completely sanitized. Right now, whatever air that is in the pot is extremely excited due to the heightened temperature relative to the outside of the container. This causes the gas to expand. As the pot cools, the air with the pot contracts causing a vacuum effect within the pot. If the lid is not air-tight, this will force an influx of the air from the surrounding environment, taking with it any microbes that may be floating around in the air.

This now contaminated, awful idea to begin with, is now left at near incubation temperatures and allowed to cultivate. Way to potentially rack up the medical bills just to save a few bucks on power.

If you're going to can the soup, that's a different story. Sanitize the canning jars before adding the piping hot soup and immediately close/torque the air-tight lid/cap and you're golden, at least for a while.

Petri dishes are not air tight and they are made for growing bacteria on nutrient agar. When I pour my dishes the agar is at approx. 90 C. Why is it that microbes are not sucked in during the cooling down process?
Sometimes the process does suck in microbes, though rarely. One of the reasons petri dishes do not allow this is because the lids are flanged downwards and overlap the mating bottoms. The rate of air flow due to cooling isn't usually enough to overcome gravity.

In pot lids, seldom do you find a lid that completely covers the top and partial sides of the pot. Most pot lids also have vents in them, either as straight holes or adjustable vents. In either of these cases airflow due to cooling pairs with gravity. Microbes can be directly sucked into your pot either through the lid/pot interface or through the vents. Also, if the microbes don't make it into the pot via a direct route, they can pool in the condensate and drip down into the pot contents in time or when removing the lid.
Very interesting !!!…
In Paris - France, kitchens of the late 19th century flats had the same ventilated cupboard called a "garde-manger" ("food saver") which was usually built under the kitchen window. It protruded on the outside of buildings not unlike the air-conditioners in modern american cities. Most of them disappeared as buildings went through renovation from the early 70's on, the refrigerator becoming a standard piece of furniture for all households.

However I always felt it was a loss, as these contraptions gave the ideal halfway temperature for a many staples.
Red wine hates cool temperature and needs a to be kept in a cooler place than the kitchen. Cheese can be kept in the fridge, but it is great to have it warm to a higher temperature a couple of hours before meal. Fruits give all their taste and flavor at a higher temperature than the refrigerator. Most "berries" have their flavor killed by the latter low temp. Eggs do not need to be refrigerated. Etc … 

I feel this is a great idea : not only is it greener (which is great) but also gives us the opportunity to eat tastier food and enjoy their full flavor.
I always thought cheese had to be refrigerated until I started backpacking with some friends who brought a block of chedder cheese with them on the trail. After hours of trekking in the hot sun, they would break out the cheese and cut off a chunck for everybody. It was soft from the heat, but tasted great and I never got sick.
GodNspired1 year ago
On the issue of storing eggs, I was watching one of the "Preppers" shows and was shocked to learn that eggs could be stored for months at virtually room temperature (naturally the cooler the better) by coating them with mineral oil! I'm guessing the mineral oil keeps them from drying out and possibly inhibits the incursion of bacteria. No, I've not tried this.
csprinkle2 years ago
I live in Mexico, where eggs are NOT refrigerated in the supermarkets. I lived in France, where milk is not refrigerated in the supermarket and it was not the ultrapasteurized variety.
Prime beef is hung to age for unrefrigerated.
In the US too much is made of "cleanliness". Use common sense. I know people who refrigerate EVERYTHING. I also know people who spray everything they touch with Lysol. We build immunity by coming into contact with "germs". That's not to say, we should touch and/or eat everything, but still....just use common sense!
People are afraid to leave anything with mayonnaise out (particularly potato salad), but it's not the mayo doing the harm (unless it's homemade mayo, and honestly most people buy it, don't they?) It's the POTATOES that are the danger...they have a high water level and can grow bacteria much faster than commercial mayo..

I heartily agree with you.

However I should say that fresh and pasteurized milk is refrigerated in France and has always been …at least till 64 years (my age !…).

The milk sold at ambient temperature in France is called "UHT" (or "Ultra Haute Temperature") where milk is pasteurized through a high temperature flash (not sure if this is the proper american technical term).
This type of milk is largely used now precisely because it can be bought in bulk and be kept in a closet thus leaving space in the fridge for other staple.

Myself I sail my 30ft boat without fridge, and we keep "UHT Milk" under the floors for months.

However I must say that this milk is less tasty than the fresh version. I like it less.
Then again it may be a generation thing : for my daughter "real" milk is UHT and fresh milk is plainly disgusting as its taste is too strong !!!…

grannyjones2 years ago
Food safety trumps energy savings.
Refrigeration has probably saved millions of lives
that would have been lost due to food poisoning.
Just think,"What is cheaper--take a chance on iffy food
versus a trip to the E.R.--or a funeral?
It's a no-brainer. Please be safe.
twighahn3 years ago
could u explain more clearly how this works.what makes the air cooler in the cc
dlginstructables (author)  twighahn3 years ago
What makes the air cooler is the climate where I live. Even in the summer, the temperature usually goes down into the 50s at night, so by having the CC vented to the outside, we can take advantage of that cooling effect. I also cool down a couple of 1 gallon jugs of water by placing them outside at night and then I put them in the CC in the morning. In the winter, the CC works even better, because it stays cool during the day also.
up in the appalachians they used to put a cold house over the river that was closest to the house.there was no floor so the cool air from the river kept the cold house cold inside even in the hottest of days.the lower part of the cold house nearly froze some foods so u had to keep that in mind when stocking it

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