bag potato

Buying Potatoes for a Potato Diet

Has this happened to you?:

At the supermarket you are confronted with an endless array of potatoes. You want to do the potato diet, but have no idea what type to buy. Here’s a guide to which one does what, which one has most resistant starch, which one is best for boiling.

Addendum: 6 moths after this was written, I received this email. Please keep it in mind as you read on!

I came across your blog, specifically an article entitled “How to Buy Potatoes,” and its filled with inaccuracies – some are noted and explained below.

-Most potatoes found in grocery stores come from storage; storages can hold potatoes for over a year if necessary  (potatoes go through a process called suberization which takes about a month – the tubers give up excess moisture and go into a dormancy state where the skins thicken up and the lenticels close – after that it’s a controlled atmosphere environment that keeps them in this state)

– The fall crop or storage crop, comprises about 91% of fresh potato volume in the nation – mostly harvested between August 1st and October 15th and provides potatoes throughout the winter months and into summer.

-The processes that take place in commercial storages are much more complex than your two sentence analysis; it’s a process that involved multiple experts and technologies

-light causes potato greening – research chlorophyll biosynthesis

-there are no validated claims that potatoes get more or less nutritious while in storage – the article you linked from 1997 is focused on processing potatoes, not fresh market potatoes – there is a difference in how the two categories are stored/handled/etc.

-Blue/purple are not a major potato type – russets are top, followed by reds, yellows, and whites

-yellow potatoes are not considered “all purpose” – in fact, they are rapidly gaining market share in the nation as gourmet potatoes

-russet not russett – check your spelling

-“marketing tricks” – “Potato distributors are just as sneaky as potato chip distributors”

– ?? sounds a bit conspiratorial on how you’ve presented it – marketing potatoes is a very low margin/high volume industry which really doesn’t provide funding for marketing tricks

-Carisma potatoes are low GI potatoes, not advertised as low carb – there was one potato in the US sold as “low carb” – it’s called Sunlite- and it’s been recently re-branded as low calorie.  Carisma potatoes originated in Australia and are marketed in several nations across the globe but are not yet for sale in America due to different labelling laws

-a 5oz/110g potato has 26g of carbs – about 17.5% of the net weight

 Ralph J. Schwartz

Potandon Produce LLC

1210 Pier View Drive

Idaho Falls, Idaho 83402

Vice President of Sales

Export Sales

1-208-520-6170 (cell)

1-208-557-5118 (office)

1-208-522-2471 (fax)


Potatoes are grown on large farms around the world. There is almost always a time during the year when potatoes are in-season. Except for seed potatoes, most of the potatoes you find in a grocery store have not been in storage for too long, maybe a month or less. It’s expensive to keep potatoes in storage. To store a potato longer than a month, it needs to be kept in a climate controlled environment and most likely will need to be treated with a chemical fungicide to keep the mold off and a sprout inhibitor to keep it from growing eyes.

Just because a potato has been in storage does not mean it is bad. It’s really hard to tell by looking at a potato how old it is if it has been stored correctly. In fact, potatoes that have been in storage longer might even be healthier than freshly picked potatoes due to the conversion of starches and sugars. A potato’s job in life is to remain healthy throughout winter so that it can sprout and grow in the spring. In nature, if a potato is too close to the surface of the earth, or exposed to where an animal might eat it, it develops poisons that give it a green appearance. Improperly stored potatoes can turn green, also. These should not be eaten. You can cut away a green spot, but if the green extends to the center of the potato, best to throw it away.


As we saw in last week’s blog post, the cultivar (type) of potato determines its carbohydrate, resistant starch, and fiber content but the preparation of potatoes has an even bigger impact. Potato distributors are just as sneaky as potato chip distributors. They rely on catching your eye and they fight for shelf space just like these guys:

There are five main types of potatoes. I’m talking about “white” or “Irish” potatoes, and not sweet potatoes and yams.

  • Red
  • White
  • Yellow
  • Russett
  • Blue

You can cook and eat any of these potatoes any way you like, but due to starch content and a couple other factors, some are more suited for certain preparations than others.

Red potatoes are best for boiling as they tend to stay firm. They also make great French fries, but due to their shape and size, the commercial French fry moguls prefer bigger, longer potatoes.

Yellow potatoes are considered “all-purpose.” These types are hard to distinguish from one another, they just look like generic potatoes. Some may be labeled “Yukon Gold” or “California White,” but they are generally thin-skinned and have a nice appearance in the produce section.

White, Red, Yellow (Ann Overhulse Photography)

Russet potatoes are the stereotypical baking potato. They tend to fall apart if boiled, but they make excellent French fries. Russet potatoes have an extra thick skin and are resistant to forming eyes. They are known for good storage ability. Choose a Russet if you want to bake, broil, fry, or roast your potatoes.

Russet Potatoes

Purple (sometimes called “blue”) potatoes are quite unique. Several varieties have deep purple flesh all the way through and some are only blue-skinned with a white interior. The blue coloration is from polyphenols, which you may remember from our discussions about blueberries. This blue color is the best benefit to buying purple potatoes, but I find them quite fickle to cook with. Lightly boiled and used in potato salads, they hold up well and give a unique color to the dish. But they tend to fall apart when boiled, so take care. They are usually too small to bake, and when sliced and fried they just turn black. But they are fun just because of how they look, so if you get a chance, grab a bag and try them out.

Purple fleshed
Purple skinned

Fingerling potatoes can be white, red, or yellow. They are specially bred for their small, elongated appearance. These are more novelty potatoes as they have few commercial uses. They tend to be an all-purpose potato when you need a small potato. They do very well when boiled, steamed, or roasted.

Yellow fingerling

They’re All Good!

When you buy potatoes, just get what looks good. You can cook any potato any way you like. Avoid potatoes with green spots or eyes. They should look fresh and be very firm. If the are soft, they were stored incorrectly and should be avoided.

As far as nutrition, each potato has unique qualities, but they are all good. What some lack in fiber, they make up for in resistant starch. Some may be higher in Vitamin C or a certain mineral, but may be lower in another. I cannot recommend one over another.

Marketing Tricks

I compared potatoes to potato chips earlier, and you should be aware that the supermarket might try to pull a fast one on you in the potato aisle. One trick I see is that they separate and spray water on old potatoes to give them a fresher appearance. Potatoes should be stored dry, not wet. Beware wet potatoes!

Ann Overhulse Photo

Low carb potatoes. These pop up from time to time. They’ve been around for about 20 years and are simply a marketing trick. They are lower in carbs than some potatoes, but not really enough to be called “low carb” if you are counting carbs. The charts we looked at last week showed that potato breeds vary between about 60-80% carbohydrate. A typical potato, 1/3 pound, tennis ball size, will have about 30-40g of carbs. Even the most die-hard low-carb diet allows this many!  I’m not really sure how potatoes got such a bad rap in low carb diet circles, just because they are easily recognized, I guess. If you come across a bag of low carb potatoes, try them out…but don’t pay a lot extra and don’t expect they will have much fewer carbs than regular potatoes.


Microwave-ready potatoes. These make me laugh. Shrink-wrapped in plastic with the directions, “Place in microwave for 7-8 minutes.”

Recognizing a Good Deal

Often our grocery store will get little bags of assorted specialty potatoes. When you see these, buy a couple. You won’t regret it. They may not be the cheapest, but you’ll get to experience some new potato magic.  The “good deal” here is not the price, but the novelty. I hear there are stores now that carry these all the time. If so, try them out.

If you have the space and a good place to store them, buy potatoes in bulk. Pound-for-pound, potatoes are the cheapest source of nutrition there is. Prices vary around the country, but I think you will usually find bulk potatoes, 50 pounds or so, selling for about $15-20 (i.e. Sam’s Club).

But the best value you’ll find anywhere in potatoes is the local farmer’s markets around your home. In most of the US, potatoes are harvested in the late summer or fall. Find a local farmer and buy as many as you can properly store. Most potatoes will keep well in a cool garage or basement. Freshly dug farmer’s market potatoes should be easily stored for 2-6 months depending on your climate and storage location.

If you have no where to store more than a bag of potatoes, keep buying them as long as they are available. Lots of these local farmers store potatoes in refrigerated warehouses without treating them with chemicals.

The price of organic farmer’s market potatoes might make you gasp, or you might be pleasantly surprised. I’ve seen “pick-your-own” potato fields where the price rivals Sam’s Club. Digging potatoes is great exercise and fun for the whole family…look into it. What better deal is there than that?


Potatoes are good food. Buy whatever you fancy, avoid marketing tricks and green spots. Buy what you can afford, but look for deals not reflected on the price tag.

Did I miss anything?



Potato Happy Dance


Comments are closed.

%d bloggers like this: