Wednesday, March 16, 2016

Buying Potatoes

Has this happened to you?:

At the supermarket you are confronted with an endless array of potatoes. You try to think which one does what, which one has most resistant starch, which one is best for boiling...well, here's the solution. It's not that hard.


Nearly 6 months after this blog post appeared, I received this email, please keep in mind as you read the rest!

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.

White and 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)

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

Russett 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 nowhere 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


  1. In my neck of the woods, you can get "May Queen" potatoes. Yellowish inside with brown skin, they stay very firm when boiled. I find no potato as delicious as May Queens, can't get enough of them, and they will be the mainstay during my next Potato Diet run.

    1. You are making me hungry! Stop!

      Gives new meaning to a line in my favorite Led Zeppelin song:

      "If there's a bustle in your hedgerow,
      don't be alarmed now.
      It's just a spring clean for the May Queen."

    2. May Queen potatoes? gotta find some of those!

      "yes there are two paths you can go by,
      but in the long run,
      there's still time to change the road you're on .."

      Sorry, but that's just weird Tim, I was humming that earlier today.

    3. If you play it backwards, it says, "Oh, my sweet potato starch...I live and die for you."

    4. You two............tsk. Weirdos.

    5. There's a line about you, too, Gab!

      "When she gets there she knows
      If the stores are all closed
      With a word she can get what she came for"

    6. "To be a rock and not to roll"

      That is telling us we need to cut our potatoes in half and not over-cook them!

    7. You're in there too Tim "the Piper will lead us to reason .."

    8. Dear lady, can you hear the wind blow?

  2. The purple fleshed potatoes are my favourite; just divine. They do cook quickly and crumble but that's what I like about them, a different texture to the crunchier white al dente cooked ones. Your teeth just sink into them. These are the ONLY potatoes that I can eat without salt, which spoils them, they are just best au natural. Well mashed with butter or cream would be better of course haha. Please grab them if you can find them.


    1. Funny, that's the way I like purple potatoes, too. Eat them like a piece of fruit. I am amazed at how dense the flesh of some purple potatoes are. When I am digging them in my garden, I often toss them aside thinking they are rocks.

      When you look at a purple potato, they just scream "I'm healthy! Eat me!"

  3. Thing about the potatoes that don't boil up good, poke 'em and when the knife goes in 1/3 of the way with ease, turn the heat off and let them continue cooking passively. Then they end up good and they don't split or fall apart.

    I boil the Russets because right now that's what I need to finish. If I boil them until they are cooked through, then they are overcooked. Skin splits.

    Purple fleshed spuds probably are the same except since most of the time they are small, possibly putting them in a steamer makes more sense.

  4. I think ALL potatoes are potentially "low carb". As I think I said before, I eat mostly a low(ish) carb diet and have been experimenting with treating my spuds more like a vegetable, minimally cooking them. I thinly slice them and fry them very briefly in butter and/or lard along with beef, eggs, onion, etc. This leaves them under-cooked/partially-raw and they have a semi chewy, if not crunchy, consistency. My logic is it preserves more of the heat sensitive nutrients. In particular Vitamin-C and RS. So far it seems it's probably working because the effect is similar to when I ingest too much raw potato starch powder - lets just say the rear-end-result is firmer without going TMI on you guys.
    That's sorta a tangent subject but logic would have told me more RS would do the opposite - move things along faster and less "firm". But that's what RS does to ME. YMMV.

    1. I actually try to undercook everything. The onions, beef, eggs. All of it. I always "wet" scramble my free-range eggs. Not to mention drinking many of them raw blended with unpasteurized milk (a post workout natty protein shake).

    2. Good advice, Brad. Potatoes have gotten a bad rap for too long!

    3. Brad - the Potato Hack fixed my rear-end D. Clean Breaks are everyday occurrences for me now. :)

  5. Fun stuff, Tim. Yummy potatoes. I eat a variety, with most of them being small. What do you mean by "too small to bake"? Do you mean that you prefer to roast them?

    1. Ah, I just meant too small to turn into the typical foil wrapped baked potato that you smother in butter and sour cream.

      Actually, these small potatoes are perfect when baked in an oven. Especially if you cut them in half and bake really hot. I guess that is technically "roasting," lol.

      When you wrap a potato in tin foil, you are really steaming the potato.

    2. I read someplace that a potato should be baked naked on a rack at the hottest temperature possible. That's how I do it.

      I make a skillet whole chicken on my Big Green Egg at 600-700 degrees. I have to wear an apron because the chicken fat flies everywhere. Well, I baked potatoes sitting right next to the skillet, and they were awesome. The skin was almost fried in chicken fat!

    3. What a funny word combination: BAKED NAKED

      Title of my next book!

      I do that sometimes, too, but they tend to ooze out potato juice and make a mess. I spent a lot of time trying to perfect the baked potato. I like to roll in olive oil, sprinkle heavily with seasalt, and bake naked on a pizza pan at about 450 deg F for 30 minutes (depending on size). Tennis ball or smaller seems best for this. The big guys, I just wrap in tin foil and bake about 1 hour at 375.

    4. Lately I've noticed a lot of "recipes" for Baked Potatoes that are cooked for 6 - 8 hours in a crock pot. Seems funny that anyone needs a recipe for baked potatoes but I wondered if cooking them for such a long time wouldn't affect the resistant starch.
      I have never seen such a variety of potatoes as you have in the first picture. Beautiful!
      When I worked in an office some of the people would bring in the sealed potatoes and microwave them for lunch. That stopped when several found mold on their potatoes once they opened them.
      Keep up the good work!

    5. I tried making them in the crock pot once, but couldn't see any reason to do it that way again. My favorite is still thinly sliced and fried in a pan like you used to make for us.

      I can't believe that microwaving a potato inside a plastic bubble is the best way to cook a potato, haha. But, I have to give credit to whoever thought of that marketing idea.

    6. I still take my large bakers, coat in olive oil and roll in coarse salt. Bake at 425. Takes about 45 mins or so. I usually put a small piece of foil on the rack below to catch any of the gurplets that might come out. Crust is browned, salty and crunchy. Tough to beat a good baker.

    7. "Gurplets" lol. I know exactly what those are! The fresher the potato the more gurpy they are, too. That's the texture you cannot get when you wrap in foil. Most excellent!

    8. This comment has been removed by the author.

    9. Ah, I've never liked foil-wrapped potatoes, so I'll keep on baking (and boiling, roasting, etc.) small potatoes. ;)

  6. What are your thoughts on variety selections to eat raw or add to smoothies? My intention is to add some for RS content. I read your previous article about the RS content of raw, cooked, and retrograded forms of several varieties, but I rarely see variety names on the taters in the stores.

    1. I wouldn't worry about the variety, more just about how it looks. For eating raw, select the freshest, firmest potato you can find. Make sure there is no green or eyes. If you are unsure of the age, treatment, or chemicals that may have been used, peel them well. Otherwise, if they are homegrown or organic/local, eat the peels as well.

  7. this is great

    1. I'd say that is a pretty bad ripoff of my blog in Spanish. It's usually considered poor form to plagiarize a blog, and then brag about it on the blog you took it from, lol.

      Mas Papas!

  8. Hey Tim, great little "potato 101" here! But, what do you think about potatoes being placed on "the dirty dozen list(link here:" Would they be "dirty" all the way through or do chemicals mostly stay on the peel.

    I normally buy my potatoes from the local farmer, but they ran out of potatoes (yes, I eat a lot of potatoes)! Now, the season is almost here, but probably I will run out of my potatoes before season comes. Should I be picky about my "marketplace options" or do I just experiment and don't bother with "the dirty dozen" list too much? Thanks!

  9. More potato porn here from the UK Tim.How the hell dowe tell which are the best varieties from this?

    1. Cool! Databases like that are for commercial potato growers who need a specific variety for their soil, marketing, or a specific pest/disease that may be present.

      For the home gardener or potato buyer, just buy whatever you like, what is in season, bulk, etc... They are all good.

      A potato chip factory will specify to a grower that they need a certain type of potato, and then the grower would look at this database to determine which breed to plant.

    2. Addictive to scroll through the different varieties! There must be over a thousand. Thanks for sharing.

    3. And to go on all those varieties Insigny Sainte Mere Normandy unpasteurised butter in Waitrose UK.A very hard butter but awesome taste,expensive but worth it.Forget jam/spread,not needed,beware very addictive.

    4. Wow, and they didn't have some of my faves, so the mind boggles at how many there must be worldwide!

  10. Tim I'm getting an addiction to the purple spuds! Granted I can't overeat them without butter, cream etc but I just want to eat them exclusively. Maybe I'm defeating the purpose of the hack, I should be eating cold unappetizing spuds from fridge to kill appetite not these little balls of crack. They seem to give me some kind of dopamine rush; is that possible? I could do a Chris Voight with these. I just hope I don't turn into the ooompah ooompah kid. I would never dare adding any butter to them to make them tastier.



    1. haha, something about blue food that makes us go crazy! Enjoy.

    2. Tim, Read thru a lot of your book today. Enjoyed the pictures (especially Jackie's stash and the quotes.) I think you've got a winner. It is easy to read & understand which is what most of us need!
      Your Proud Momma!!

    3. Thanks, Mom! I finally git my copy today, too. I think they did a great job with the binding and cover. Some of the pictures don't look as good in black and white as I hoped they would, but all of Ann's pictures look really good.

      Did you see the Jack LaLanne hat? haha

    4. Paula

      you should be proud! It is a very good book, all well explained, even some complex science.

      I thought "Jackie's stash" must be some kind of insider joke... LOL Are there more?

    5. I needed a picture of processed snack foods for the RS4/5 section. It was not hard to come up with a pile of candy in this house. In fact, now I am surrounded with chocolate Easter eggs!

    6. Very carefully remove the foil, replace chocolate egg with a potato shaped 'egg'. Rewrap....... mwahahaha!

  11. The low GI potatoes are half the calories if you believe what they say, 45 calories per 100g compared to normal potatoes 86-100 (depending on your source). Just thinking aloud for people hesitating if coming from LC or think they may over-consume.....


  12. Do you recommend eating the skins or removing them?

    1. I prefer to eat the skins, but it really depends on what they look like. Sometimes it's easier to peel them than clean them.