The Official French Fries Pages:
How Do They Make French Fries?
We've finally cracked the industry and got ourselves a couple moles! These people have generously agreed to donate time and information (but no trade or corporate secrets) in order that we may provide even more information on French Fries. We'd normally give names and E-Mail addresses so you could send thanks personally, but we've been asked not do so. OK.
How French Fries Are Made:
Step 1: Get a lot of potatoes
The potatoes used in the production of French Fries come either directly from the producers (farms) or from rather large warehouses, depending on the location of the processing plant and the time of year.
The potatoes are checked for solids content (how much water vs. how much non-water), grades (how good the spud is) and sugar content (is it too old?).
Fun fact: More than 2.2 million metric tonnes of potatoes grown annually in the US (49% of total potato production) become French Fries! We meant it when we said to get a lot of potatoes.
The most commonly used potato varieties in the US are Russet Burbank, Ranger Russet, Norkota and Shepody. In Continental Europe, it's the Bintje and in the UK, the Pentland Dell or Russet Burbank. If you're playing along at home, the type you're most likely to find is the Russet Burbank (a.k.a. Idaho Russett), although the Yukon Gold, Yellow Finn and Saginaw Gold are also good varieties and have the added bonus of a yellow flesh, which, when fried, has a really nice colour. If you can't find these, try some other variety. Many of the greatest scientific discoveries were made accidentally.
Step 2: Peel them
While we have discussed various potato peeling methods elsewhere on this site, it seems the most common method in the French Fry industry is the steam method, in which a whole lot of tubers are put into a rather large, pressurised tank which happens to be pretty hot, too. After enough time, the pressure is quickly released and the potato skin is said to fly off. Other sources have discounted this and told us that the skin is merely well-loosened by the process (maybe these other people need to use more pressure). We imagine this looks really neat anyway and have been told that our imagination is correct, but we have yet to see this first-hand. When we do, so will you.
After the potatoes come out of the peeler vessel, they're sprayed with high-power water jets to remove any peel still clinging. The removed peelings are either processed as cattle feed or run through a system which lets them decompose and uses the resulting methane to offset the energy needs of the plant.
For home peeling, we recommend the tried-and-true hand peeler; use of a pressure cooker might work, but forcing the explosive decompression would be difficult and could be dangerous and the select ware, inc. legal staff have directed that this page warn you not to do it.
If you don't have your own cattle, potato peels make a great soup stock or compost. For high-pressure spraying, we suggest befriending the boys at your local firehouse, although a garden hose with a sprayer attachment or even simply a bit of running tap water from the kitchen faucet will do.
Step 3: Inspect them the first time
The naked potatoes run past an inspection line where sorters remove any potato which looks defective (clear potato rot or bad shape or anything else that might cause problems). There are also machines to do this step, and we hope to provide more information on them some time soon.
The rejected potatoes are taken away and mascerated (ground up) and the resulting potato starch is used in things like chemical glues and papermaking (as sizing or binder). They don't waste a thing!
If you don't want to waste a thing, save the good bits for soup stock and the black yukky bits for compost. Or find a page on the Web to learn how to render your very own potato starch.
Step 4: Cut 'em up!
Next stop is the cutter. We really need to put a picture of this thing up. The potatoes go through a centrifugal pump and are shot out at about 50mph (80 km/h) at some stationary blades which chop the tuber into what the industry calls "strips".
And you thought potato cannons were cool?
Oh... waffle-cut and spiral-cut potatoes are cut through a "dry" process using other specialised machinery. They take a lot longer to produce. Of course, these aren't "real" French Fries, so we won't lose too much sleep over them here.
It is possible to get a mechanical French Fry cutter for home use. They are sold at restaurant supply shops. Most of these cutters are only able to cut large-bore French Fries, though. A regular knife will also the job quite well. We recommend using a high-quality chef's knife. If you're a fan of the late-night half hour commercials, flip around the channels and you may come across an offer for a waffle-cut or spiral-cut tool for only $19.95 plus shipping, Nebraska residents add local sales tax. Sorry, no CODs.
Note: the Official French Fries Pages do NOT carry or sell these items. Sorry.
Step 5: Inspect them again
This time, all the little chips and bits (like the quarter-round bits left which come from the outer edge of the potato) are removed, as are any strips with black bits (which weren't visible during the first inspection). This black bit removal is done through automation. Cameras and detectors notice the discoloration and the entire strip is knocked out of this machine to another. These machines are pretty high-tech and can inspect and decide the fate of up to 1,000 strips and chips each second!
In this second sorter, more sensors detect bad bits and automatic knives remove them. The bad bits are sent to masceration and the leftover good bits (and all the little chips that are too small to be French Fries) go on to a new life as hash browns or tater tots elsewhere in the processing plant.
For the home version, you'll just have to pay attention when you cut your potatoes and remove both the good and bad chips by hand. The good chips could be used in hash browns or mashed potatoes or soup. The bad bits go to the compost heap. You do have a compost heap, don't you?
Step 6: Blanching
The twice-inspected strips have made the grade and are now on their way to being processed into French Fries. The next step is blanching. Despite the picture shown here, blanching is actually done with the strips on a moving conveyor chain which carries them through a rather large vat (or a few vats) of hot water. The time and temperature of the blanching is adjusted continually in order to remove excess sugars and to give a consistent, uniform colour.
Sometimes sugar is added in a dip after the blanching process. Odd, isn't it?
Unless you're a pretty hardcore French Fry fan, you won't have the measuring and testing equipment around to ensure the proper sugar content of the strips, so you'll just have to eyeball it and experiment a few times until you get it right.
Step 7: Drying
The next thing to do after the blanching is to partially dry the strips. Once again we've taken a bit of creative licence. Strips are not normally dried with the type of dryer pictured (except maybe in the home version of this game), but we haven't been able to get pictures of the real thing. This instrument should, however, be satisfatory for home use.
Basically, the strips stay on this chain-belt and after they come out of the water, they go through another machine which blasts hot air from both the top and bottom, partially drying the chips... sort of like the dryers at automated car washes. Of course it doesn't dry them completely, but again the amount of drying is regulated depending on the water content of the potatoes.
We're starting to get the idea that water content is even more important than we first thought. If a company that makes a few million pounds of French Fries says this is how it's done, we're not going to argue.
An interesting note is that the water content adjustments are made according to the desired end-product. If the French Fries are meant to be deep-fried, the water content will be around 70-75%; if they're to be cooked in an oven, 65-70%; for microwave French Fries, it's a measly 55-60%. The reason has to do with the amount of water normally lost through each method of cooking and with a little luck, all three versions will be almost indistinguishable from each other when served.
(True connoisseurs will probably notice at least slight differences between these types -- there's just no pleaseing some people.)
Step 8: Par-Frying
Now we're back in familiar territory. The "par fry" (or "partial fry" is a cooking stage where the strips are cooked for a about a minute and a half in oil that's a bit hotter than normal French Fry cooking temperatures.
All frozen French Fries are par-fried at the manufacturing plant before you fry them completely at home. This is one of the reasons that when you cook French Fries at home, they just don't seem the same.
The par-fry in European chipshops (notably in Belgium and the Netherlands) is a bit different. They cut their own potatoes, then cook them at a lower temperature for a few minutes. The par-fried potatoes are removed from the fryer and left to cool slowly (usually a for a few hours). They are then cooked a second time just before serving in a much hotter "shock" fry to make them really crispy. Most of the steps to this point are not done in "chipshops" or "Frietkot" or whatever they're called in any particular country.
Step 9: The Deep Freeze
The final step is blast freezing of the strips. Blast freezing is a method that freezes the French Fries which travel down on the wire conveyor using air cooled down to about -40° (Celsius or Fahrenheit -- they're same at -40) so that only small ice crystals form. This prevents them sticking together and helps protect the flavour.
If you're playing along at home, you could use a carbon dioxide fire extinguisher. Otherwise, you'd probably need liquid nitrogen and some heavy insulated gloves. Once again, our legal department has told us we may not recommend or condone the practice of home experimentation with liquid nitrogen. While the results can be interesting and fun, there's always some chowderhead out there who will do it wrong and hurt himself and then sue us for not telling him not to do it. So don't do it.
Step 10: Wrap 'em up and ship 'em out
After the processing is done, the French Fries are bagged and/or boxed and shipped out to their final destinations (distributors, restaurants, supermarkets) where they are then cooked to order. You don't want French Fries which have been cooked more than about 5-10 minutes in advance since they get limp, greasy, soggy and cold.
You won't need to ship them out at home. After all this work you've probably built up some appetite, so why not do the final fry immediately and enjoy some of the fruits (or vegetables) of your labour?
Do you work for a French Fry manufacturer? Do you have some inside knowledge that might help us further and better inform the world about French Fries? Can you get us into a Frecnh Fry producing plant? Contact us please. We're not above writing large thank-you letters and posting them on the site and leaving the company logo in all the pictures (if necessary). We're also not above removing said logos at any company's request.
This page could not have been created without the kind assistance of Mr Ken Wilmot of McCain Foods in the UK and another gentleman who has asked not to be identified (one of our industry moles). We are grateful for their time, effort and patience with us.