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How to make McDonalds french fries (seriouseats.com)
396 points by dpatru on June 6, 2010 | hide | past | favorite | 93 comments

I worked at McDonalds long ago, and I am a huge fan. If you are interested in understanding why they are so incredible, make sure to read "Grinding It Out" which is the story of McDonalds told by Ray Croc, who turned a small local store into one of the greatest franchises the world has ever known. He was in his mid-50s when he stated, and the whole thing is just inspiring for entrepreneurs no matter how many time you might have failed before. But I digress...

The thing about working at McDonalds is that you learn exactly what everything tastes like - and you notice all the little changes. For example, the difference in quality between a quarter pound patty used in the quarter pounder and double quarter pounder, and a "10" (1/10 pound) patty used in the regular cheeseburger and double-cheeseburger. I have eaten everything on the McDonalds menu, and can tell you what the most disgustingly unhealthy thing by caloric density is (not the fries!).

So, the most important factor we noticed about the french fries was how old the fry grease was. Each night 1 of three things happen to the fry grease:'

1) it is skimmed for any remnants of fries and left to simmer at a low warm temperature for the next day

2) it is run through a cleaning machine (2-3 times per week)

3) it is completely replaced by a technician (every 1 or 2 weeks depending on time of year)

New grease is very clear, like fresh motor oil you put into your car. As the grease gets older turns more and more golden brown as it gets more carbon in it from little bits of fries that break off and burn in the hot oil and disintegrate. Eventually, right before it is replaced, the grease is very brown and the fries will actually come out with tiny brownish bits on them. Some people really liked the "dirty grease fries" but the majority of staff knew when the best french fries were made - when the grease was about 4 days old, right after the first cleaning. I can't tell you exactly why, but these fries were the yummiest to the point where I would only eat them at this point (gotta stay thin somehow working there!) and crew members would bring in their kids on that day to eat.

Its also important to know that fries are never ever cooked in the same grease used for chicken nuggets, fish filets, etc. I'd be curious to know what that tastes like if anyone has every broken the rules and tried it, but that was a religious issue at the McDonalds locations I worked at so we never did.

Anyway, if you're curious and have a regular McDonalds you can always ask them when the last time the grease was cleaned or changed.

You really should have been filtering your oil ("run through a cleaning machine") daily. The filtering process removes the carbon build up that causes oil to degrade. The labour cost to doing this daily is far smaller that the cost of the oil you save.

Yeah I agree, and I think the oil replacement cost is pretty high (one of the top monthly line items after people expenses). McDonalds provides guidelines to franchises and then they decide how to implement, in our case we lived in a small town (an island actually) and I think the cleaning guidelines are "per X batches cooked". But yes, generally the more frequent the better both for the oil and also for the vats.

Since MacDonald's is the Ford assembly line of today I'm pretty sure they know what they're doing. Especially with thousands of "restaurants" around the world.

I worked for the company, and you're right - they do know what they're doing. That's why stores are expected to filter daily.

The one I worked in (in Scotland) did.

Fries aren't cooked in the same oil as the fish fillets and nuggets because of vegetarian concerns. Never tried the fries in any oils other than its oil (mainly because they were in different areas in the building).

The oil of the fried chickens (the nuggets, McChicken patties and Crispy Chicken patties (maybe more or less different types depending on what country you are from)) are kinda interchangeable.

>Fries aren't cooked in the same oil as the fish fillets and nuggets because of vegetarian concerns.

That seems unlikely, considering that the fries still contain "natural beef flavor."

I thought that was urban legend and that they just contain "natural flavor" which is unspecified and McDonald's is very tight-lipped about what it actually is (to the chagrin of vegetarians who would actually eat at McDonald's).

It maybe different per country

I'm an ex-MCD, and we never did fries (or hash browns) in the fish or apple pie vats because the taste would carry over. You don't want fishy-tasting fries.

The oil in the fry vats, when it got too old for fries, was put into the pie or fish vats.

> Its also important to know that fries are never ever cooked in the same grease used for chicken nuggets, fish filets, etc. I'd be curious to know what that tastes like if anyone has every broken the rules and tried it

The fries would pick up the flavor of the fish or pies and taste weird. Since the vat temperatures are different, and the vat sizes are different, the fries would not come out consistently fried either.

For those who enjoyed reading this post, I have some recommendations:

* Anything by Hervé This (http://en.wikipedia.org/wiki/Hervé_This#Bibliography)

* Nicholas Kurti's "But the Crackling is Superb: An Anthology on Food and Drink by Fellows and Foreign Members of The Royal Society of London" (ISBN 0-7503-0488-X)

* Stuff by Heston Blumenthal (http://en.wikipedia.org/wiki/Heston_Blumenthal)

I first learned of the obsession with perfecting food through understanding the chemistry behind it through Cook & Chemist (http://www.cookandchemist.com). Unfortunately, the two books they have published are in Dutch and there appear to be no translations yet.

May I add 'On Food and Cooking' by Harold McGee (ISBN 0684843285)? McGee also writes at http://curiouscook.com/.

On Food And Cooking is an awesome, awesome book. It's on my bookshelf next to my reading chair; I flip it open to a random page any time I get bored. The charts and sidebars alone (for instance, breakdowns of the volatiles in different herbs and spice) are worth the price of admission.

It's also written absurdly well.

-1 redundant. These are heros of mine as well.

The major influence Heston Blumenthal has had in my (sparsely equipped kitchen) is this: fennel should be microwaved. Wrap the stuff in microwave foil and zap it five times for one minute (leaving time inbetween to allow the heat to dissipate).

Best fennel you've ever had.

Also works with asparagus.

microwave foil? Am I missing something -- by "zap" it are you really suggesting putting aluminum foil in the microwave -- or is that something else.

Microwave foil is a sturdier version of cling foil. Which is plastic, so perfectly safe to put in the microwave.

This is an incredible site, I just read http://www.seriouseats.com/2010/04/cook-your-meat-in-a-beer-... on a whim and am trying it tonight.

Very cool.

I have done that twice now. It works amazingly well, especially if you have a good grill to finish them on.

Broken record: if you're liking the results you're getting from the beer cooler, drop a couple hundred on a PID-controlled rice cooker setup. You don't need to shell out for a Sous Vide Supreme appliance to get professional results (in fact, a friend who wrote a review for the SVS was hard pressed to come up with any advantage to the SVS over the "ghetto" setup, other than that it doesn't make your kitchen look like a meth lab.)

With mix of professional and personal curiosity I'd like to ask: what control do cheaper rice cookers use, and what does PID add? Super precise temperature control with no oscillation is the only thing I can think of -- is it that important?

Rice cookers don't include PID controls. They have "hot" and "warm". You can cook with them (Roger Ebert had a great blog post about his one-pot wonder dishes), but that's essentially a gentle form of crock pot cooking.

Super precise temperature control is one of the most important developments in all of cooking. If you have it, you can take almost any protein or almost any vegetable, select a final cooked state out of a (tiny) book, punch it into the control, and walk away for an hour, an afternoon, or a fortnight and come back to a 100% guaranteed perfect product.

Three example implications:

* You can buy $30 steaks, bag them, throw them in a rice cooker in the morning, go to work, come home, and have them perfectly rare-medium-rare all the way through. I'd say "better than at a steakhouse" if so many steakhouses weren't apparently switching up to cook steaks this way.

* You can take a tough braise cut (short ribs, octopus), bag it, stick it in the rice cooker for a couple days, and pull it out medium rare and tender. Tender medium rare short ribs are a novel product of precise temperature control; you can't do them on a grill.

* You can take a vegetable and cook it at a target temperature that breaks down starches but not pectin and get unique textures out of them. Keller, who has obviously better equipment than we do, combines this with compression to get steak-like textures out of things like melons.

What are you bagging your steaks in? Paper bag?

What setting are you using? Cook or Warm?

Seal-a-meal. Paper, water, and hours: not a good recipe.

I'm not using "Cook" or "Warm". I'm using a small box with a PID controller, into which is plugged my rice cooker, and which is itself plugged into the wall. A small digital thermometer checks the temperature of the water that fills the rice cooker and modulates the power to keep it within a degree or two of the set temperature I want.

Right now, a pair of rib eyes and some tilapia filets are being held in there at 129f. In a couple minutes, I'll pull the fish and stick it in a smoker for a couple minutes, then sear both sides of the steak for 10 seconds or so, then plate and serve.

(Tilapia SV at 129f for 2 hours, then 10 minutes in a smoker? Beautiful. Like bacon fish. Kids ate it up.)

It's a vacuum seal plastic bag and you let the pid controller keep the bath at a temperature a few degrees warmer than you want the steak to finish at. Take them out of the bag and sear them really quickly and you have perfect steaks.

Here is a great guide if you want to look further: http://amath.colorado.edu/~baldwind/sous-vide.html

My gf just pointed out the potential danger of heating plastics. I googled, and found this: http://camping.about.com/od/campingrecipes/a/ziplocbaggies.h...

That article talks about boiling a plastic bag, whereas sous vide is usually no hotter than 140° F.

McDonald's main problem is that they sacrifice quality for consistency. I can understand why a chain restaurant would want that. I can even understand why a customer would want that. What I can't understand is why a home cook would want that.

Pommes frites are fresh potatoes cooked in animal fat, and seasoned with salt and rosemary. http://www.flickr.com/photos/stuart_spivack/4205683848/

If you read the article, he actually tries to improve on McDonalds fries. He says they get soggy too quickly, and tinkers with the recipe to achieve longer crispness.

"McDonald's used to fry their potatoes in beef tallow, giving them extra flavor and making them extra crisp, but they stopped doing that years ago."

Something home cooks can still do.

I am pretty sure they stopped doing that when trans-fat became really unpopular, and it also might have to do with making their fries edible to people who keep kosher, vegetarians, etc. -- that's the tough thing about literally serving billions of people

They stopped doing that when saturated fats became unpopular. Beef tallow doesn't contain trans fats. They stopped using beef tallow long before most people even heard of trans fats. If you are going to recite nutritional dogma at least get it right.

sorry, I think its dumb dogma

I worked at McDonalds at various times during the 1970s and 1980s. What went into the fry vats was labeled "100% vegetable shortening." It looked exactly like Crisco - execpt it came in large bricks instead of cans.

I did remember hearing folks claiming they used beef tallow back then as well.

I am pretty curious about what the effect would be on flavour. Animal fat is pretty bad for you though, and probably much cheaper to come by so I imagine those are just a few reasons to go with vegetable oil over animal fat.

You're right about the cost. I worked for McD's during the transition to vege oil, which drove down the profit margin of fried products considerably. Given that you need a handfull of high gross profit products (fries, coke, coffee, etc.) on the menu to alleviate the burden of low gross profit products (happy meals, anything healthy, etc.) the decision to switch really hurt.

Didn't affect the flavour much though. Not a single customer approached us about it at the store I worked in. Though if you took fries from two different batches, each cooked in different oil, and concentrated really hard, you could just make out the difference.

I've never fried anything in tallow, and while I keep good lard (and bacon fat) for confit, I never fry with it. However, I do fry things in duck fat, and it makes an enormous difference, both in flavor and mouthfeel.

The "best" french fries are, it's said, fried in horse fat (I first read than in Steingarten, a dubious source, but have heard it backed up repeatedly). If you Google, there's an article with someone actually tracking down horse fat and frying frites in it.

Anything fried in duck fat is better :)

In fact, now that I think about it the only thing I do with my carefully hoarded supply is use it for frying and confit. I wonder how well it works for tasks that otherwise are better with lard (e.g. pastry pie crusts, etc.)

Ever use it in place of lard for a baking task?

No. I really ought to. My understanding is that it plays approximately the same role as 50/50 oil/butter would.

(Eggs. I also do eggs in duck fat.)

You probably already know about it, but there is a place in the chicago area called "hot doug's" that makes duck fat french fries on fridays and saturdays. They also have wonderful sausages.

Hot Doug's is awesome, but the line is reliably 40 minutes long. You can phone orders ahead, but Hot Dougs doesn't keep well. If you're going to go out to Avondale for a sausage and some fries, you might as well suck it up and stand in line.

The Publican, at Fulton Market, makes duck fat fries. It too fills up quickly, but they open at 3.30P every day and don't get crowded 'til 5.30 or so. And: absolutely fantastic beer list. So that's your best bet in Chicago.

In retrospect the beef lard was probably no worse than the trans-fat oil they replaced it with (they have since eliminated the trans fats).

But the prior poster is correct... McDonalds fries have never been as good since they stopped using the beef tallow.

Actually "I read somewhere" years ago, mainstream publication citing a then-new study, that trans-fat oil works in the body in some meaningful way 30x worse than animal fat. The details are too snore-inducing to remember. Just eat lots of vegetables and it won't matter if you eat a small bit of whatever.

Some people - me included, rarely as I eat them - prefer McDonald's fries to most others.

I agree. I don't each fast food much at all, but the only craving I get is for McDs fries. When they are done right they very tasty regardless of how unhealthy they might be :)

I used to prefer McDonald's fries, and I still prefer them over other fast food, but most bars and sit-down restaurants seem to have better fries to me now. (And, unlike McDonald's, they will give you barbecue sauce.)

I've never had a McDonald's refuse me barbecue sauce, mcchicken sauce, etc. whenever I ask for it, regardless of what my order was.

More recently they will only give you one bbq sauce with their chicken nuggets, and even asking for an extra one isn't free. Asking for bbq sauce w/ fries is an extra charge.

Responding to you first two sentences, I don't think that's actually a bad thing. It's very far from being the best food ever but it has a consistent quality - you can walk into any McDonald's restaurant anywhere in the world and you will know exactly what you will get. Sometimes (especially when you travel) you don't have that many options when it comes to food and you know that at least you won't get food poisoning at McDonald's.

The vinegar hack is brilliant. Cooking is chemistry and should be treated as such.

I wonder if cream of tartar would work. (I really hate vinegar, it smells like rotten food to me.)

Well, it is in a sense.

That is some serious reverse engineering

You know you're awesome when you bust out the micrometer to systematize the rendering of perfect french fries.

That's actually a dial caliper, not an outside micrometer.

Well wither me toes, I've been calling them micrometers my whole life. Thanks!

Not only that, but it's a Starrett caliper: the kind of pricey, high quality tool that I drool over.

...and about the only interesting part of the article. I enjoy cooking and I love potatoes; I even have a dozen or so potato plants/tubers/whatever growing in the garden. But even I realized years ago that the key to good french fries with low effort is to buy the OreIda "fast food" fries and cook them myself in the fat of my choice.

I've tried all the methods I read about and still the premade ones are better. Something I've never been able to say about any other food I cook.

My dad the machinist prefers Brown & Sharpe or Fowler (depending on the particular tool) to Starrett. Styling mostly; it seems like Starrett stuff has the old fashioned look and typefaces, whereas the B&S has a more 60s clean and simple hi-tech look.

I actually have the same model Starrett dial caliper pictured in the link.

If you liked all that, you'd probably enjoy the tv show "In search of perfection" by Heston Blumenthal, which is all about optimising common recipes (supposedly in a manner reproducible in a domestic kitchen, although I'm often a bit skeptical about that part).

The first episode I saw was on fish and chips too.

Was it something like this?


Great, I just lost like 20 minutes.

Lot of attention to details. I liked the part where due attention was given to those without a temperature controlled water bath. Awesome!

The way McDonalds makes its fries isn't a secret. They let Food Network film part of a documentary on fried food in one of their french fry factories, and showed the entire process from potato to frozen product ready to ship. It was basically cleaning and sizing (large potatoes cut in half), shot through pipes by water pressure with a grate on the end of the pipe that cuts the potato into fries, steamed to make the inside fluffy, then fried twice at two temperatures.

That's kind of like saying that the way Google processes mail for Google Mail isn't a secret. It's not, but knowing how "it's done" and knowing how they "actually do it" are two different things.

prove that algorithmically, thank you.

I think the point is around things like "What temperature do you fry at?", "How hot should the steam bath be?", etc. The details make all the difference.

9 ! = 362 880


(define (factorial n) (let fact ([i n] [acc 1]) (if (zero? i) acc (fact (- i 1) (* acc i)))))

Incidentally, 9 != 362 880 is also true.

While that may be true, the interesting thing about this article is that it presents a recipe that can be reproduced in an average kitchen. I'm no chef, so I don't know if this has done before, but if it hasn't, it's pretty cool.

It has been too long since I had a fry party. I think I'll try this.

A fry party is exactly what it sounds like. You make kilos of fries and dozens of dips and get drunk on the power.

With a bit of social engineering... aka "asking someone who works in a McD kitchen"... he could have got the oil cooker temperature and timings.

The McD website, or a pamphlet you can get instore, would list the ingredients.

Anyway, kudos to the writer for doing it the hard way.

Finally, telling a McD fry lover (I put my hand up to that!) that the fries are rubbish is like telling a smoker that cigarettes are bad for them. We know.

> asking someone who works in a McD kitchen

While that may have answered the "how", only through this type of process could the author have answered the "why".

...as well as discovering how/why _not_ to do it, which can be more valuable knowledge.

Okay, I'm just not used their taste.

Nothing is better than fresh potatoes, made by my wife with feta cheese on top of them and beer. I like them to have some meat in them.

I really don't like fries of this style. I'll take a real, honest fench fry where one can tell it is made from a sliced potato. Five Guys, for instance, makes excellent fries. They appear to do so by cutting up a potato and immersing it in boiling oil. Imagine that!

I have absolutely no desire to eat processed, partially synthesized corporate potato product.

Some interesting stuffs - Patents related to French fries.


I have the RSS feed of this site for quite some time and this site delivers every single time with amazing recipes.

tl;dr but this reminds me a lot of "The Quest For French Fry Supremacy", a two part article on Cooking Issues.


Hmm, I'm not sure I get the downvotes - is it the "tl-dr" part ?

No biggie, but it'd be a shame, the article I linked to is as impressive, it not more in terms of cooking-engineeringness.

Yeah, I would guess people don't like "Hey, I didn't actually read this, but here is something that I imagine must be related." (Even if it does turn out to be relevant and worthwhile.)

True, but I can also see it from the other side: "I feel that I have something worthwhile to contribute, but I don't have time to read the entire article, so I'll just post it here in the hopes that someone finds it interesting/relevant."

I think that it would be somewhat of a stifling approach to just make a blanket proclamation that no one can enter the discussion unless they have full read the article.

Just leave out the tl;dr part. You don't need to justify your posting of a link. Just post it and say what it's about.

OT: why do you have two accounts?

I am curious to know - do they use preservatives or unnatural additives?

They don't know how to make anything without preservatives and additives. They don't care. Of course they're full of absolute death wax, not to mention all the petro/organochlorines the potatoes, canola, corn and soybeans were probably soaked in while being grown (highly likely to be genetically engineered, too)

here you go, from http://nutrition.mcdonalds.com/nutritionexchange/ingredients...

Potatoes, vegetable oil (canola oil, hydrogenated soybean oil, natural beef flavor [wheat and milk derivatives], citric acid [preservative]), dextrose, sodium acid pyrophosphate (maintain color), salt. Prepared in vegetable oil (Canola oil, corn oil, soybean oil, hydrogenated soybean oil with TBHQ and citric acid added to preserve freshness). Dimethylpolysiloxane added as an antifoaming agent.

CONTAINS: WHEAT AND MILK *(Natural beef flavor contains hydrolyzed wheat and hydrolyzed milk as starting ingredients)

This is one of best blog posts I have ever read!

I prefer darker, unblanched fries.

The premise is wrong. I mean, McDonald's fries are about OK as far as frankenfood goes, but they are really horrible compared to anything home-made with fresh potatoes, no question about it. They're too small, they have absolutely zero taste, they're greasy... This is supposed to be a model to follow? Gimme a break.

This guys picked something he likes - McDonald's fries - and did some impressive food-hacking to revere-engineer and improve them. Regardless of your thoughts on the thing he's imitating, surely you can respect the rigor and discipline the author applied to the problem.

He's not saying "this is how you make the world's best fries" - he's saying "if you really like McDonald's fries (like I do), here's how to replicate them". If you don't like that type of fry, then don't make them.

I'm all for the food hacking and the article was quite interesting, however I shivers to the idea of McDonald's as a cooking reference.

He clearly defines the characteristics that make a good french fry and then explains how to match that consistently. He concludes that almost all of McDonald's practices (freezing the fries) are not simply economically important, but essential to the taste as he defines them.

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