Last April, I wrote a post about leaving stock out on the stove top claiming that it would be safe to eat provided that you brought it to a simmer before eating. Indeed I've been doing this for a decade with no ill effects. On twitter and on the post itself, I received voluminous responses. One response, from a large-animal veterinarian, noted that it was entirely possible for heat-stable toxins, not bacteria, to persist, making the stock unsafe. I revised the post with the vet's valid warnings with links to the CDC's warnings on the particular bacteria.
But the response was so strong, I suggested in an email to NYTimes food section editor Pete Wells, that this would be a great story. I've left stock out on the stove top for up to three days because it was convenient, simmering once every 24 hours, but I'm not scientist or a bacteria expert? Really, what are the dangers? On the one hand, I've been doing this for years. On the other hand, I've done enough reading about the bacterium that causes botulism to know about how difficult spores are to kill and that they can indeed lead to food toxins that can make you sick, particularly in low-oxygen, protein-rich environments, such as the inside of a sausage, or a stock pot.
Wells asked food science authority Harold McGee to address the issue, and he does so head on in today's NYTimes in an article headlined "Bending the Rules On Bacteria." In it, he writes that leaving stock on the stove top for up to three days is in fact a risky procedure, boiling or not. It's not the bacteria that are the issue. Bringing stock to a simmer will indeed dispatch them. But some spores, not killed by boiling temperatures, can hatch bacteria, which, over time, can multiply and produce toxins that are not killed by boiling temperatures and can make you sick. So I hereby stand corrected and am glad Wells chose McGee to address the issue so thoroughly.
To clarify what McGee writes in his article (he relies on O. Peter Snyder, a veteran food scientist and consultant to the food-industry, for expert testimony), while many of the government recommendations regarding food safety are overly conservative, caution is always advisable. I have never gotten sick from stock I've made, and I would never be stupid enough to leave cooked food out at room temperature for three days and then eat it. And by simmering it the next day, as McGee himself confesses to doing, before chilling it, I feel comfortable serving it, I would now suggest that after bringing the stock to a boil the second time, that it's best to strain and chill the stock rather than to leave it out. I hope it's obvious that from a flavor stand point—that is if you're not being lax during a busy work week, or contending with a stuffed refrigerator—it's best to strain, cool, and chill stock (or any food that you're not going to eat right away) immediately, the sooner the better.
McGee notes that even playing fast and loose with the rules with stock, provided that it's boiled, it's impossible to say what the odds are regarding food sickness: "What are the actual odds of getting sick from casual food handling at home? No one really knows. There are many variables involved, and only a small fraction of illnesses are reported, even to a family doctor, since they’re usually brief."
Interestingly, though, with rice and other starchy foods, McGee notes that the dangers are very really and very serious indeed:
"In 2008, a 26-year-old Japanese mother in the Osaka region shared a meal of leftover fried rice with her two children, ages 1 and 2. She had prepared and served the rice the day before and kept it at room temperature.
"All three became ill 30 minutes after eating the leftovers, and were hospitalized. Both children lost consciousness, and the youngest died seven hours after the meal. Pathologists later reported in the journal Pediatrics that the rice contained a very common spore-forming bacterium, Bacillus cereus, along with a heat-resistant toxin that the bacterium tends to make on starchy foods, and that can cause vomiting even after being heated to the boil."
And as I write this, I recall that the animal vet mentioned above, in supporting the conviction that food left out can make you sick, noted that he had recently become very ill after not reheating a stir-fry enough in the microwave. Apparently, even hammering the rice with heat wouldn't have made it safe.
In an email yesterday, McGee noted something else: "One thing I've found that didn't make it into the piece is that people are discovering new microbes and toxins all the time—there are a half-dozen Bacillus relatives that make heat stable toxins, but they haven't been studied enough yet to know how common they are, what foods are most susceptible . . . all of which I think argues for general caution. Again, we think we know more than we really do."
Ok, enough lecturing. All the above wouldn't have been worth the trouble except for one fact: homemade chicken stock is an amazing thing, not only a great ingredient but a great tool that can transform your cooking. And it's not necessary to make a major project of it. Make just a little. The following is a recipe and pix of how I make small batches of chicken stock all year long. It take minutes of actual labor, not hours. And it's a wonder.
Having Made And Consumed the The World’s Most Difficult Chicken Recipe here's what you do:
Easy Chicken Stock
- Chicken bones and scraps from the devoured chicken
- 1 onion chopped
- 1 or 2 carrots chopped (I peel them for photos!)
- 1 bay leaf
- 1 teaspoon black peppercorns, cracked
- optional: tablespoon tomato paste, garlic, thyme
- Combine all ingredients in a 2-quart pot, cover with water, and cook over low heat (no bubbles, 180 degrees F/82 degrees C is ideal) for 4 to 6 hours or bring to a simmer and put it in a low oven (below 200 degrees F/93 degrees C) for 4 to 6 hours (I sometimes just leave it in overnight).
- Strain the stock. (I don't find this so much with chicken, but beef stock can take on an unpleasant boney flavor it the bones are left for too long). Allow the stock to cool. If you're making it at night and don't have time to let it cool enough to get it into the fridge before turning in, then bring the stock to a simmer the next day for five or ten minutes. Allow it to cool, then refrigerate it.
- The stock will be good in the refrigerator for a week and can be frozen for several months (after which it will pick up undesirable flavors from the freezer).
The following are pix from start to finished stock:
If you liked this post on stock, check out these other links:
- My post and recipe for corn tortilla soup.
- An interesting article from Khymos.com Meat Stock from a Molecular Gastronomy perspective.
- A fresh summer tomato sauce with stock and olive oil recipe from Luculus Den.
- Learn more about Harold McGee at his site the Curious Cook.
© 2011 Michael Ruhlman. Photo © 2011 Donna Turner-Ruhlman. All rights reserved.
Wilma de Soto
Thanks for the clarification. Not all of us have cast-iron stomachs and steel backbones.
melissa
Thanks for posting the clarification!
(I thought this was going to be about consommé!)
I got a pressure canner a few years back and it's changed how I do stock. Now, I do it on a weekend - I make an enormous batch of it, let it cool a bit (boiling stock + muscle twitch = second degree burns...I still have the scar on my stomach), and then strain and pressure can the lot in quart jars. That way I don't take up valuable freezer space and it stays both shelf stable and delicious until I need it.
And if I have beef bones, I'll make some beef stock in the crock pot the night before and can that too. 🙂
It really is one of the best things I've ever done for my pantry - I'm not constantly making stock this way but I always have a ready supply.
which reminds me, I'm down to only 2 quarts left...I see a stock-making weekend in my future!
john v phipps
Thank you for pulling at the loose threads. I leave stock out often. Will need to retrain myself to not do that.
Kevin Locke
Michael,
To cool a stock before putting it in the frig or freezer - I remove the bones and solids from the stock and cool the stock in the pot in a sink full of cold water. The food scraps go into the yardwaste container for curbside pick up in many of the Pacific NW towns and cities - rather than the landfill.
Laura @MotherWouldKnow
Thanks for an illuminating dialogue with Harold McGee. How to prepare and store food to avoid sickening oneself and others is an important part of learning to cook. My European friends laugh at my attention to food safety and I cringe at their tendency to leave cooked food at room temperature for hours and days. Some of our "rules" & customs are cultural, but food safety is what motivates my tendency to refrigerate asap. Now that you and Harold McGee have me thinking about rice - what's your practice about storing plain cooked rice, how about when mixed with meat?
ruhlman
i've emailed harold about rice, we'll see what he says.
Dave M
We kept our friends' dog for several days and he provided us with a large container of cooked chicken and rice. After about 4 days (in the refrigerator of course), it went off - I think due to the cereus bacteria on the rice. The dog turned her nose up at it a day before we noticed it and threw it out.
Charlotte
That was the most interesting part for me, since I've been known to leave rice in the rice cooker overnight, then hit the "warm" button to reheat. Won't be doing that anymore. Scary.
As far as stock, like the commenter above, I do tend to hoard up carcasses and do a big batch at once, then pressure can. But in the winter, we often set a big pot of stock, or pot roast, or stew out in the mudroom to cool over night. We're in Montana and with wood heat, the main living areas are warm, but the "extremities" of the building stay pretty cool. I always reheat before either serving or freezing for later.
It was a great article -- thanks for suggesting it.
Drew @ How To Cook Like Your Grandmother
Maybe next you could have them look into raw eggs in mayonnaise. I know that it's the potatoes in potato salad that go bad, not the eggs in the mayo, but I don't have the right initials after my name to convince people.
ruhlman
i never worry about eggs, especially if I'm using organic ones or ones from a local farm.
DiggingDogFarm
Life is full of potential dangers.
Bacillus cereus can potentially exist in breads and other baked goods such as pies (especially those containing ingredients known to be high in bacillis cereus, such as rice) that are kept at room temperature.
Victoria
I read the NYTimes article this morning. Thanks for issuing this clarification.
Michael Ruhlman! I LOVE LOVE LOVE your bad-ass perforated spoon. My Sunday poached eggs were picture perfect without having to snip away the loose ends with kitchen shears. You are brilliant! I have your tasting spoons but haven't had a chance to try them out yet.
ruhlman
thanks victoria! help me spread the word!
Sarah
I've always left rice out on the counter for days and then reheated it, and I've never been sick before, but I will definitely change my ways. Leftover rice will go in the refrigerator from now on! Thanks for the advice.
Cristina
I make chicken soup by cooking a whole chicken in a big stock pot with water, bay leaves, spices, carrots, onions, celery, garlic, etc. I cook it at a simmer... is 180 degrees hot enough do make chicken soup in this way? Can I have a less cloudy stock AND a cooked chicken?
ruhlman
absolutely!
Robert
From the title, I totally thought this post was going to be about consomme. J/S
Rhonda
Make your food with Love.
Infuse it with love and gratitude for the people you get to share it with.
Ruhls, why are you listening to these people?
You know better.
Rusty Wright
Have you tried making stock in a pressure cooker? (One of the new generation ones; for example, Fagor.) It takes only an hour.
ruhlman
I have, it's awesome.
jeff
i have always been confused by the pressure cooker stock - i guess it makes sense (the high pressure extracts all the good stuff), but the extreme temperature cooking seems the EXACT OPPOSITE of the traditional stock approach, of the barely bubbling pot...
does it produce a different product? does it work better for chicken or veal? i need to try it some time...
Wilma de Soto
I would love to know more about pressure cookers. We call them The Cuban microwave although I am skittish about using them and which dishes would benefit from them. You explain things quite well. Which types would you recommend and will they be featured on OpenSky? Thanks.
karen downie makley
I am in the "you-can't-be-too-careful" camp for all food items. But I see no reason NOT to make a big batch of stock. Refrigerated, it's good for a few days. Frozen, it's good almost forever.
Carolyn Z
Bought a set of spankettes from OpenSky. They are great for sauteing veggies. The shape makes it easy to flip them over. Also we used it to remove a whole chicken from a clay pot. Just slide it underneath and lift up the bird. I wouldn't have thought that would work. It's wonderful that they are long, 15 inches. One has stained but otherwise they are so pretty. A very useful kitchen tool. Also thanks for the $5 credit.
Natalie Luffer Sztern
Very good post. My entire life my mother always told me that if ever I left food out on the counter overnight including soup I would have to throw it away...whether that was the way she was taught and whether that had to do with refrigeration etc. back then, I don't know. Interesting though that I have always had that mindset for all foods except of course fruits and some veggies (but only in their raw state) - anything cooked always had to go in the fridge or in the garbage...
Cristina
I make chicken soup by simmering a whole chicken in a stock pot with water and vegetables and seasonings. Since you advise cooking stock at 180 degrees, do you think a whole chicken should be cooked in water that is that temperature too? Can I get less cloudy stock AND a cooked chicken? Thanks!
(sorry if this appears twice, I am having trouble with my connection)
Natalie Luffer Sztern
...if I were on a game show and the winning answer would be worth some bucks and the question was ...'what is the difference between stock and soup.." I would, after reading this blog for so long, be able to answer and that answer would be..".a stock has bones and meat and vegetables whereas a soup does not have to have meat/bones..." so would I win the million?
Maddy
No celery? I don't know why but it surprised me that you don't include it.
JW
Some folks (Thomas Kellar and others including me) feel that celery may add a bitterness to the stock. I perfer to use as a garnish.
jeff
i winder if this falls under the category of the over-paranoid information overload society we live in today...
yes, one very unfortunate family died... people die of shark attacks now and again... i just hope that all of this food paranoia (did i re-heat the leftover stir fry sufficiently??) does not lead people to be more afraid of their food and cooking, and go to McDonalds for every meal (resulting in the hundreds of thousands of people who die from heart disease and the such each year...)
JJ
Thanks for the great info. I've been trying to convince my friend that overnight cooling is not necessarily a good idea.
On a different note. I like to leave some of the the chicken fat alone and let it solidify, acting as an air tight cap for the stock. I still use the lid to the storage container, but my thinking is that less air exposure would mean less degradation to the flavor. Plus it makes it easier to separate the fat from the stock. Opinions?
Judy in SATX
What do you think of simmering the stock in a crock pot until you have time to strain and cool it?
Anna
The only time a stock went bad left on the stove was when I heated the oven underneath to make some roast. It fermented and got sour. Nevertheless, I try to be on the safe side and keep stocks in the fridge, and always bring them to a boil before serving them.
commiskaze
Ive always been in the camp that, at a professional level doing things with the utmost care is of paramount importance. At home I am much more bendable when it comes to food safety. I think more often then not food safety involves a little know how, some common sense, and usually very little extra effort -so why not? That said I think everyone would have better luck winning the lottery then getting botulism.
Jason
It's concerning to me that a person with so little understanding of food safety, and being so nonchalant about it, is the author on multiple books on curing raw meats.
Mary
This is a worry to me as well. I had to suspend many of the food safety rules I know when making the dry cured sausages from "Charcuterie". I have not had a problem so far, but am wondering if I've just been lucky.
When I first read the McGee article, I thought I either misread it or he was misquoted. Stock is like agar, an almost perfect medium for microbial growth. I do all I can to not invite food borne illness into my kitchen.
commiskaze
I think that maybe with a little know how and research you would realize what you need to watch for and what you dont. This man who has done alot for educating food does not need your uneducated snide remarks. Thank You
Mantonat
I talked to the local owner of Colorado's only USDA certified salumeria about food-born microbes. He said the number-one concern for him is listeria, which he also said is very rare in the home kitchen.
I've had severe food poisoning four times in my life and I know exactly what and where I ate on all of those occasions; four professional kitchens. I've never gotten food poisoning from home-cooked food.
chuck
Funny, I took my ServSafe certification with an EPA scientist who implored us to clean our home fridges regularly with a bleach solution due to the strains of Listeria that can now thrive between 32 and 38 and are prevalent in home kitchens.
Grant Colvin
My current approach to stock, which I saw somewhere on the net: Put the ingredients in a plastic roasting bag. Put the bag in the pot. Add the water into the bag. Press the air out of the bag and seal it with the supplied plastic tie. Put the pot into a 200F oven. Leave overnight. After removing the pot from the oven and allowing everything to cool, you--and a helper perhaps--can (carefully!) suspend the still-full bag over a colander-topped pot or other container (cheesecloth optional) and snip a corner of the bag, allowing the stock to drain into the colander while retaining (almost) all of the solids in the bag for easy disposal. The use of the bag guarantees that volatile compounds will remain in the stock instead of wafting (albeit pleasantly) around the entire house. Incidentally, before you try this, you'd best verify that when you set your oven to 200, you are really getting 200, instead of, say, 213, which would ruin the whole deal.
Charlotte
I'd be more afraid of the plastic than of the germs ...
allen
I just made a batch of stock and cooled it with frozen water bottle dropped in, and then to the fridge, but I am still much less squeamish after your first post.
I hope there are no health concerns regarding the aged egg nogg, I have quite a bit that will be 2 years old this xmas, please, please let the liquid gold still be good.
ruhlman
if it's got the alcohol in it, the eggnog will be good.
darren
I still recall the chicken stock recipe from Modern Cuisine that's made in a pressure cooker. That could be safely left at room temperature since the heat inside gets so much higher. It would be like the shelf stable stock you can buy at a grocery store. Until you opened it, then it would need refrigerating. Or recooked at pressure. I've never done this and really don't plan on it, but I'd feel comfortable that it'd be safe.
kat
For those (like me) unwilling to make a mess straining their stock through cloth or cheesecloth, I recommend one of those giant gold mesh coffee filters. Easy to clean and reuse. Anyway, thanks for looking into this! I will cool stock more promptly in the future.
John K.
I've been making my own stock in the oven using my roaster ever since I read your post on that technique. I just love it -- so simple, so good. I now NEVER buy stock. I can and freeze it, and always have an ample supply of chicken, turkey and beef stock, thanks to you Michael. I have a growing bag of pork bones in the freezer, and am eager to try that next.
John K.
Akron, OH
Epicuranoid
Longer contact time with the bones and flavorings, even in a cold fridge, yields a richer more gelatinous stock -- which is why Escoffier writes of making some stocks over days not hours.
While it's probably best not to let the stock go in and out of the danger zone too much. Something as simple as turning it off and covering it overnight, so in the morning you can begin another full day of simmering, is less likely to make you ill than a poorly maintained electric toothbrush, but it is certainly possible under very specific circumstances.
Saffoula
I love you, Michael, and I'm no scientist, but the idea of leaving the stock out unrefrigerated as described made my stomach churn. On the other hand, in countries like the Greece and Turkey they leave casseroles with meat and cheese and other "hot" food items sit out all day, evidently with no health issues.
Randy
Mike, I always thought that you put in the refrigerator, but my wife is Mexican and it is very much in the indigenous culture to leave the food out for at least a day. However, for someone who has had salmonella twice and suffered through camphyllbacter with my kid, food safety is the king. I appreciate you being willing to see all sides and this is a good important debate
Will Price
Mark, since this discussion have you left out your stock overnight as you have been doing for years or did you change your ways? just curious..
ruhlman
I have indeed left it out overnight, and into the next day, resimmered it, cooled then fridged it. Again, ten years of leaving stock out three or four days, making sure to simmer it each day for ten minutes, has never hurt anyone here. And a number of friends have reported the same. That said, the experts should be heeded. Moreover, the only reason to leave it out is it's easier, not really a good enough reason to take any chances; and besides, the flavor's better if it's properly chilled and stored. So the rule now is, fine to cool on the stove top over night, but store it the next day after resimmering.
Kearby
We generally boil down our stock and freeze the concentrated stock in small portions to add to recipes as needed. I assume freezing is a good way to kill lots of foodborne nasties, no?
ruhlman
actually no, it's not; bacteria survive freezing well. the trichinosis worm does not.
Chuck shaw
Why no celery in your stock. I was taught by Chef Kuntze to use the standard 2:1:1 mirepoix ratio. Is it just a personal preference?
ruhlman
The stock is sweeter and has a better flavor without celery. I use celery in beef stock.
Reiner
Someone mentioned concerns about rice left in the rice cooker overnight. I think it's common practice here in Japan - but with the rice cooker left on its "warm" function, of course. My wife has been doing it for all the years I have known her, and long before then as well. We eat rice with all three daily meals, and we cook a batch and keep it for up to about 24 hours. I don't believe we've ever been sick from this, and I assume it's safe to do, but I'd be interested to hear any opinions on that. It wasn't something I did myself before I married, but we've done it for so long now I barely even think about it.
Reeder
Interesting stuff. I regularly leave my stocks out overnight and have never got sick yet still, a little more caution and quicker refrigeration is not going to mess with my life too much though and if i'm honest it's a good reason to clean the stove top down instead of being lazy.
Not sure if anyone touched on the subject of Chinese Master stock in the comments? The process of re-using a stock over and over again to poach foods and add flavour without ever using all the stock in a soup base or other complete way. Some restaurants in Beijing even claim that their Master Stock is over 100 years old! The stock is handled carefully to stop spoilage but in the past this must have been done without refrigeration and i'm sure the process would not have continued if it was associated with food poisoning.
I also sometimes worry about how sanitised our lives are these days and the association this has with our increase in allergies but thats another thing all together.
http://en.wikipedia.org/wiki/Master_stock
Pat
When I'm having people over for dinner, I usually make a lot of the meal the night before, including stock for sauce, or for a gelatin terrine. I simmer the rabbit or chicken & veg in a closed pot with a tight lid, then leave the huge hot pot overnight on the stove. I've been assuming for decades that this was OK because I have essentially "canned" it by heating it and keeping a lid on it. At Thanksgiving, my fridge is FULL of other things - especially the big bird - with no room for a huge pot o' stock. And I don't want to wait for it all to cool down anyway, I want to go to sleep. In the morning, I strain out the cooled fat & veg and heat it up again to reduce it. Do you think that with new strains of bacteria this is now dangerous? I don't want to make anyone sick. Love your column, this is very helpful.