Everybody: Why Resistant Starch Has to Be Raw & Cold

We get this question all the time in comments, so here's something to refer to next time someone says something dumb, like, "great, gonna bake brownies with potato starch next time."

You have to take it raw. This means, stirred into any cold or warm beverage or food of your choosing. If you take it with any of the foregoing that's fermented and let it sit for just a while, here's what happens:

NSFW: Probiotic Bacteria Fucking Resistant Starch Granules

That's right. Most probiotics die in the stomach and small intestine giving you expensive shit. FODMAP and other fermentable fibers do their thing when they get there. Resistant starch is the only prebiotic I'm aware of that actually gives probiotics a bus ride to the colon. Speculative, but I have an idea that they might help with small intestine bacterial overgrowth (SIBO) by gradually having those bacteria attach and get taken down to the colon (where they belong) via normal bowel function. That's why I think it's good to take your potato starch sometimes on an empty stomach with just water.

What happens when your get bacteria get fed? Lots and lots and lots of things. You'll have to read up.

...Anyway, you can't cook this stuff. Think of it as microscopic popcorn. Bob's Red Mill Potato Starch is about 80% RS, 20% water. Yet, it's a very dry, fine powder. Well, how much moisture is in a bag of popcorn? It's inside the kernels. Just like RS. When cooked (about 140+) it bursts. Here.

IMG 2106
Bacteria Food

But take that spoon, stir it up in 4 oz water and nuke it for a minute?

IMG 2110

You get regular, fast digesting starch. Or, hair gel, if you're running low. Take your pick.

Alright, are we clear on all this?


  1. Are we not counting the retrograde starch in cooked and cooled stuff anymore? I loves me cold potato salad :-(

  2. Any advantage to mixing kefir (or other probiotic) with PS and letting it sit awhile? Or just mix and down it.

  3. Fuck! Now you tell me (although you probably did). I’ve been mixing two heaping tablespoons in my scrambled eggs every am. Very tasty actually.

  4. Just re-read. I’ll rephrase. How long should the mix of the probiotic and PS sit?

  5. I’m gonna go ahead and blame you for the fact that Bobs PS has doubled in price in the last month. Fucker.

  6. gabriella kadar says:

    Ozquoll, if you check the resistant starch in cooled potatoes it doesn’t come anywhere close to RPS. That’s the point. You can eat your cold potatoes and enjoy them, but don’t expect the same results.

  7. You stole that container of ps out of my fridge…I know you did.

  8. @Ozquoll

    Sure. Use ‘em all you like. Hard to get more than about 10-15g. You can make up the balance to 30g with 2T of this.


    Tim says it attaches immediately. I like to let it sit a few, keep gently stirring it, downing it over another some minutes. Since I don’t know for sure, precautionary principle, hit all the bases, etc.

    @Joe B

    Scambled eggs are probably not hot enough to destroy much of the RS. What I’d do is turn off the heat, add in a pat of butter or, the old fashioned way is you withhold about 2T worth of the egg and put that in to stop the cooking. Once that’s done, should be cool enough to add the PS. To make sure, do all the foregoing, plate it (cools even more), then measure with a therm. If under 140, you’re good. Even if not, the PS itself will cool the mixture so you might be converting some to rapid starch but certainly not all.


    Well, you weren’t looking.

  9. “I’m gonna go ahead and blame you for the fact that Bobs PS has doubled in price in the last month. Fucker.”

    Lessons cost money. Good ones cost a lot.

  10. MsMcGillicuddy says:

    If we were to stock up on Bob’s PS, presumably best route is to store in the dark and cold? any estimates as how long it takes to expire?

  11. Allan Folz says:

    I like the pop corn analogy. It paints a picture that is very easy to imagine and remember.

    And yeah, yeah, to all the pedants… it’s not perfect, no real-world analogy is. It’s just meant to help ‘teh normals’ remember sh*t.

  12. gabriella kadar says:

    MsMcGillicuddy,since RPS contains no fats it won’t go rancid. Storing it in the cold is probably not necessary. I’d think putting it in the cupboard until required is sufficient although since it’s pure white, light won’t degrade anything.

  13. gabriella kadar says:

    For whatever reason, the instructions on the bag of Korean potato starch instruct to mix with liquid and let it sit. I’m assuming this is because moisture will puff up the starch prior to using it to coat meat or fish prior to frying. I have not let it sit prior to consumption so I don’t know if there are any textural changes. But since there’s lots of moisture in the stomach, probably letting the starch absorb more moisture by letting it sit prior to consumption is not necessary.

    It doesn’t make plain milk much thicker. It does seem to make kefir thicker though. I add a bit of water to thin it down when I mix with kefir.

  14. I’ll be goddamned if I’ll pay double+ for potato starch. Solution: raw potato smoothie. Not bad. Blendtec for the win.

  15. NewYorker says:

    I eat raw plantains all the time now. If you purée one raw plantain with a splash of cream or coconut milk, avocado, tbsp of MCT oil, tsp of honey, dash of salt and some berries (optional) then it tastes like a banana smoothie. I like to have this smoothie in the evening because it provides food for the brain and honey induces better sleep. Sometime I add a few dark chocolate sprinkles on top and it’s almost like eating Chunky Monkey ice-cream. Yum. The most delicious dinner ever. I am obsessed :)

  16. Hey Richard,
    One thing I’m still not clear on is fried rice, why is it OK too reheat the rice?

  17. @NY

    I did my first test with a couple of tsp raw honey (TJ’s) last night before bed, along with 3TBS PS. Fab sleep in spite of a bit too much whiskey during afternoon and Sunday Night Football (Go 49ers!). Usually, with too much drink like that I’ll wake up with pee issues, thirst issues, or heartburn issues. Last night, nothing until like 4am when the badder had to be relieved (we’re talking minute long piss).

    Too soon to know anything, but since you mentioned, figured I would. Don’t take too much stock in my single night n=1. But I’m going to try it again, regularly.

  18. “One thing I’m still not clear on is fried rice, why is it OK too reheat the rice?”

    2 reasons. First is that RS4 (retrograde RS from cooling) is resistant to heating. Different resistant starch structure near as I can tell, not like virgin RS that’s like popcorn with a bit of moisture in the granule.

    2nd, that high heat frying really doesn’t warm heat it all the way through like say nuking it does. Best way to do fried rice is as soon as they start popping, it’s done.

  19. sootedninjas says:

    yeaj. kefir + 2 tsp Honey was just outstanding … freaking awesome ……. forgot to do it tonight but tomorrow I’ll add 1 tsp of 100% cacao powder…… better yet drink it during breakfast with a meal of garlic fried rice, 3 eggs over easy on top and fermented dried fish with dice tomatoes and onions plus a pinch of Himalayan salt. bammmm……..

  20. Hey Richard,

    I’m from the Netherlands, and I have yet to see a potato producing company to sell unmodified potato starch here. However in the international supermarket I did find Fufu flour, containing cassava, plantain, and some potato starch. Any idea as to how much RS is in there?

  21. Anyone tried Hi-Maize for resistant starch? For now I’m using potato starch but I’m curious.

  22. MsMcGillicuddy says:

    Thanks gabriella, appreciate it. I am thinking in 2014, there might be a run on PS, so maybe I need to stock a few more bags, lol…. I’ve previously kept items like corn starch around a long time without issue, but noticed they put expiry dates on the bottom of the packages – perhaps to keep us buying more, lol – thanks again!

  23. @Koen

    No idea, so how about experiment and let us know. Different RS size granules are likely favored by different bacteria, so could be an excellent mix. One way to test is do 4T in water, test BG at 15m intervals over a couple of hours. If you don’t get much of a rise, then it’s mostly RS.

  24. NewYorker says:

    How much RS in 1 raw green plantain? Confused because Tatertot wrote in one of the recent posts that the number is 50 grams of RS. But, in the Perfect Health Diet book he is quoted saying 100 g of RS per plantain.


  25. Richard,

    How to video on making potato starch.


    Economic viability aside, this could help people that don’t have access to potato starch from the store

    It would be better if the demonstrator looked a little more…evolutionarily desirable.

    Doing some quick estimations based on this video, it seems like your looking at 100 potatoes for a reasonable amount of starch if comparing to a bag of Bob’s (but at least you’ll have a year’s supply of hashbrowns).

    It seems that a finer potato grind would produce greater yield.

  26. Has anyone tried using potato starch to make a non-Newtonian fluid yet? If effective, it could be used for both health and entertainment! “Hey kids, check out this liquid, No wait its a solid! I better eat it before it melts!”

  27. I doubt it would work because it sinks to the bottom so quickly.

  28. @NY’er – I broke down the RS content of a plantain by factoring 54% RS by weight and then getting about 80-100g of dry matter from a dried plantain. I think a plantain will have 30-50g depending on size and ripeness.

    This is where I got 54%: http://ift.confex.com/ift/2004/techprogram/paper_24360.htm

  29. Tater,
    Been doin the RPS for several months now and I have not been able to get any break from the HOT putrid stench coming from my ass. I understand why you want to create the “flood” with 4 TBS on and empty stomach but do you see any down side to breaking the dose into 3 over the course of the day?? This seems to be the best way to minimize the cloud of stink that follows me.

  30. NewYorker says:

    Excellent! Thanks for the reply.

  31. About the fried rice, I saw this while I was studying to see if my rice beer contained RS or if its waste product did :)

    I’m sure this study has already been cited, but here is the money quote:

    “The crystallinity of retrograded amylopectin is lost following re-heating to approximately 70°C, whereas temperatures above 145°C are required to remove crystallinity of retrograded amylose. This is a temperature well above the range used for processing of starchy foods. This implies that retrograded amylose, once formed, will retain its crystallinity following re-heating of the food. ”


  32. I’m not sure if Hi-maze has been cooked or not so I can’t answer that. Everywhere I’ve seen it, it’s been more expensive than raw potato starch, so unless you already have it at home, it would be best to just go ahead and purchase the cheaper rps.

  33. Spanish Caravan says:

    I’ve tried Hi-Maize. It definitely works. Is it as effective as BRM PS? I can’t tell except that it’s very strong and I definitely benefited from it. I only tried it because my eyes dried out while on PS and Hi-Maize made my dry eyes worse. So I’m now only doing Barry Farms plantain flour. I have to say plantain flour doesn’t seem to be as strong as PS or Hi-Maize.

    The only way for you to get Hi-Maize that is gluten-free is from King Arthur’s:


    This supposed 5 lb. bag is not gluten-free, although commenters say they are.


    You need to purchase a 50 lb. bag for it to be gluten-free.

    Here’s my ranking.

    1 – Mung bean starch: Strongest
    2 – BRM Potato Starh & King Arthur Hi Maize Corn Starch = Strong; Roughly Similar in strength
    3 – Barry Farm Plantain Flour = Ok but not up to par with PS or Hi-Maize

    4 – Lall’s Plantain Flour = I can smell something sweet and my blood sugar rose to 130 after 15 minutes. I don’t know what’s in here. There may be sugar or some stuff we’re not expecting. Smell it and you know it’s not pure 100% plantain flour.

    5 – BRM Tapioca Starch/Flour: Weakest. Actually, we now know that this isn’t really RS2

    • @Spanish Caravan
      “5 – BRM Tapioca Starch/Flour: Weakest. Actually, we now know that this isn’t really RS2″

      How do you know this?

  34. @Spanish – What source of mung bean do your source. I’d like to get some to round out my trifecta! Oh, and glad to know Barry Farms passes the test. I wasn’t 100% sure.

    I’ve mentioned in other comments but while the dogs are pretty meh with PS mixed in their food, they seem to really like the plantain.

  35. Spanish Caravan says:

    It’s a non-descript Korean brand from an Oriental Market here in Fort Lee. There isn’t even a brand name and it looks like private label. All it says is Mung Bean Starch. That’s why I bought it but I know it works because of how much heat it packs. 1 tbsp of that got me overheated and I had to turn on a fan to cool down.

  36. gabriella kadar says:

    Spanish, why would mung bean starch pack heat? What’s that about?

  37. Spanish Caravan says:

    Mung bean starch has more amylose than potato or corn starch. So although there is less RS2 per gram in mung bean, it seems to be stronger than PS. I took 1 tbsp and my temperature went over 99 quickly (thought not over 100). I never experienced hyperthermia with PS, plantain flour or Hi Maize.

  38. Maybe Lall’s was made from ripe plantains. Ripening is a starch to sugar process.

  39. Wenchypoo says:

    I tried the unmodified potato starch in making gravy, and it only worked once on Hubby. The second time, his BG climbed about 30 points, so we aren’t doing it any more. Maybe gravy was a bad choice fof use (now that I see the COLD part of your article)?

    Maybe I’ll try it in homemade ice cream or something. Starch, BTW, is what makes ice cream creamy.

  40. “I tried the unmodified potato starch in making gravy”

    Then you gave yourself rapidly digesting starch.


    No fucking maybe about it. You didn’t even make the slightest attempt to follow instructions.

    There are nearly 50 posts on this since April, and the temperature aspect has been mentioned a million times. You have nobody to blame but yourself. And anyway, it takes like a rounded tsp to thicken gravy. I do it all the time.


  41. How bout this 2lb bag of mung bean starch on ebay for 12 plus s&h:

  42. gabriella kadar says:

    I bought a jar of Plantain Flour yesterday just to try it out. Did not test BGs. Some other time. This stuff needed some good stirring to get it into the kefir. It’s also smoother than potato starch and has a pleasant mild flavour.

  43. Spanish Caravan says:

    BTW, that looks like the right one. But the only way you can be sure is if you test your BG. I would think though that the process of drying and grinding mung beans is less involved: just dry and pulverize them, I would think. I could be wrong but I don’t see why anyone would treat mung beans with heat. The only thing I’m worred about is antinutrients. I’m gonna test my BG with the 2 mung bean starches I have after taking some Garden of Life Digestive Enzymes. I’m allergic to mung bean but I wanna see if these enzymes reduce my reaction.

    I also bought something called Mugwort Powder (ingredient=black beans) and Acorn Starch. Mugwort Powder probably has somewhat more RS than raw black beans, which have 18.3g per 100 grams. If I react to mung beans, I’ll react to black beans. But I’m curious what my digestive enzymes, which supposedly helps digest legumes do.

  44. Spanish Caravan says:

    Here’s one more n=1 experiment with Potato Starch. This time, I bought a potato starch manufactured by Hyundae Foods, which is a Korean brand. I’m trying PS to see if these digestive enzymes help reduce nightshade reaction. So along with PS, I took 2 tablets of Garden of Life Raw Enzymes for men, 1 tablet of Prescript Assist probiotic, and 1 tablet of AOR Probiotics-3, and a half cup of water.

    Start: 86
    15 min: 98
    30 min: 107
    45 min: 97
    60 min: 86

    What do you make of this? There seems to be a glycemic response but doesn’t rise as much as BRM Tapioca Flour. Could probiotics or enzymes raise BG? I shoulda done it without the pills. As for nightshade reaction, no, the enzymes don’t help. My eyes still dry out. But then I only started taking them 2 days ago. I’ll continue.

  45. Spanish Caravan says:

    Another n=1 BG experiment, this time with dehydrated green plantains. I bought big, ugly green plantains, skinned and sliced them lengthwise, and fan-dried them for 2 days. They harden and taste like crackers. They’re hard and there’s no moisture — actually, moisture is trapped inside; you’ll notice if you keep them in a bag or put in a container with a cover, they’ll soften. I just keep them laid out on a tray. I ate 50 grams of that, which should be equivalent to 26 grams of RS2. In parentheses are temperature.

    Start: 86 (98.0)
    15 min 84 (98.4)
    30 min 99 (98.2)
    45 min 110 (98.2)
    60 min 96 (98.1)
    75 min 102 (97.9)
    90 min 101 (97.9)

    Whoa! I was expecting no BG uptake but there is. Notice the glycemic response is slower than the PS, which is powder and the absorbable portion would hit the blood stream from the small intestine quicker than the plantains. So BG stays elevated longer and there is also my BG reuptake taile, typical of biphasic insulin secretion.

    I was expecting them to behave like Barry Farm’s plantain flour (which may be green banana flour). These were green plantains. Could it be that some of them were yellowing, thus lowering RS content? Or is BG rise unavoidable with dried plantains? Next time, I’m gonna do an n=1 with 100 grams. That should gauge things more clearly. The temps don’t tell much.

  46. NewYorker says:

    If I eat a raw plantain in the morning, I get lots of flatulence in the evening. Is this normal? Wonder why it takes so long to get gassy and if that indicates a problem with digestion.

  47. @NY’er – It should take about 4+ hours from eating to farting. Takes that long to travel the small intestine and get fermented in the large intestine. Maybe you have slower than normal peristalsis in the small intestine.

  48. Two questions:

    1) Does heated potato starch (“popped” popcorn) form *any* resistant starch at all during a freeze/thaw cycle? Or is it toast, so to speak?

    2) Say you took converted/parboiled rice, cooked it, froze it, and then placed it in a food dehydrator. Then, take that dehydrated mass and run it through a grain mill. What kind of resistant starch content would the resulting flour contain? Or, what if you took cooked/frozen converted rice, ran it through a food processor with a little water to form a paste, and then dehydrated sheets of that rice paste? Would that be a decent RS rice cracker?

  49. Joe:

    1) Don’t think so but can’t recall why right now. Probably because in food, owing to the fibers and structure, and cooking time/method, there are degrees of how degraded and it’s still all in the same place. With RS you have a big blob of pure starch, nothing else. Have you done the two tsp mixed in a glass of water, bucked for a minute test?

    2) Seems to me it would be about the same, although I don’t know how small those RS3 structures are so potentially a mill will shred them apart. food processor is probably a better bet.

  50. I called Bob’s Red Mill. Their potatos in the Unmodified Potato Starch are boiled before processing. Where the hell can you get that they are anywhere near 70 percent RS? Not possible. Please let me know where you pulled your numbers.

    • Michael

      We’ve been over this a million times. BRM is just a packager/marketer and their info is wrong. We’ve contacted the manufacturers.

      It’s raw PS. We’ve moved beyond that because all you need to do is get potato flour (which IS cooked) and sort out the difference for yourself. Make your own (search youtube) and compare to BRM. BRM is 100% raw PS.

  51. When left in water for 2-3 minutes my potato starch does not turn into a gel, instead the starch stays sitting down in the bottom of the glass and it needs to be stirred hard to dissolve again, otherwise it’s just sitting. Does this mean this the bad modified potato starch, or is this OK?

    • I believe it is supposed to act like that. The easiest way for me to take this stuff is to get one of those really small cooking wisks with a long handle. Dump the PS in a glass with water. I stir, drink, stir, drink and voila–my dose is done. No trouble, no cutting, no drying, no soaking, no trolling grocery stores, no pounding, no other shit that just takes up time and requires me to make recipes happen or other crap like the endless hassle some people are doing to themselves. Easy peazy. In fact, I chug my raw liver “pills” with it and get on with my life. “insert smiley emoticon face here, if I knew how to do it”. Cheers.

  52. First, I made the error of mixing my BRM in hot water, like a tea .

    Anyway, I have questions:

    I make my own kefir from raw milk (a2 cows) and am hoping that I am getting enough probiotics from this. Should I be mixing my BRM in my kefir? Do I take my 4 TBL of BRM in the morning or – should I be splitting this up between morning and night? If I take 4 TBL of BRM, should I NOT also eat raw potato? How long before I get any results?

    I would love to see an article about how to take potato starch, what foods to eat with it, lots of results from other people, etc. thanks. W

  53. Allison Filderman says:

    Does anyone know if the organic potato starch from frontier herbs is modified or raw? Thank you!


  1. […] Isolated RS, Like Bob's Red Mill Potato Starch (NOT to be confused with FLOUR), has zero carbs if taken raw, because you don't digest it, your gut bugs do and if they don't, it passes right through. On average, humans can process about 60g per day. If cooked, it's about 10g carbs per TBS (per the label) of rapid digesting starch. Don't cook it unless you intend to, like for thickening a sauce (see here). […]

  2. […] All of these indigenous cultures that favored meat ate their animals raw. Raw animals. Raw "animal starches". Raw starches. This all sounds very familiar. […]

  3. […] Agora que estão todos iniciados no assunto, vamos ao que interessa: como comer isso? E de preferência de um jeito gostoso. Lembrem-se que não vale esquentar.  […]

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