Tip: How to Check for the Hotness of Jalapenos

Ever take home a jalapeño chile pepper from the grocery store and have it either be so lacking in heat it may just as well be a bell pepper, or so hot a speck will create a raging inferno in your mouth? Here’s a quick tip for choosing jalapeños that can help you decide which ones to pick. Jalapeño chilies progressively get hotter the older they get, eventually turning bright red. As they age, they develop white lines and flecks, like stretch marks running in the direction of the length of the pepper. The smoother the pepper, the younger, and milder it is. The more white lines, the older and hotter. Red jalapeños can be pretty hot, if they have a lot of striations, but they are also sweeter.

jalapeno-hotness-2.jpg

If you are trying to avoid the hottest jalapeños (say for a stuffed jalapeno dish), pick the chiles without any striations. If you are looking for heat, find a red or green one with plenty of white stretch marks.

Note that this is just a guideline. There is still plenty of variation among individual peppers. You can find hotter-than-Hades peppers without any white lines. But your chances of picking a mild one are better if you go for smooth. Or if you are looking for heat, you will more likely find that in a pepper with lots of lines.

Update:

I would like to clarify here that this tip is based on absolutely NO scientific evidence. I was complaining to a Mexican chef friend of mine one day that I kept on buying jalapeños with no flavor and no heat, and he pointed out to me that I should look for peppers with a few striations (but not too many). I have seen this approach mentioned by others (online), but who knows what is really going on? I do know that they are developing much milder variety of jalapeños these days. I also know that the capsaicin, the chemical that gives chiles their heat, is concentrated in the seeds and ribs. The flesh of the chile that is closer to the seeds will be hotter than the flesh near the tip. This is established fact. Perhaps chiles that are more mature have more of their capsaicin distributed throughout their flesh than the younger ones? Perhaps hotter varieties of jalapeños develop striations and milder ones do not. I have never eaten a mild striated jalapeño. But several times I have bought perfectly smooth, beautiful jalapeños only to be disappointed in their complete lack of flavor and punch.

So, please take this tip with a grain of salt. Since using this approach I have not encountered a dull jalapeno. But as I said, I don’t really understand the how’s and why’s of it, and am only taking guesses at what might be going on.

71 Comments

  1. secretnatasha

    Thanks for the tip! I wish it were easier to find red jalapenos – I love them.

    I grow jalapenos and have noticed that even after I’ve picked them while they are still green, if I don’t use them up right away, they will turn red in the kitchen counter bowl where I’ve placed them. Sort of the way that a green tomato might continue to ripen after it’s picked. Doesn’t happen all the time, sometimes they just wither instead of continuing to ripen. ~Elise

  2. Greta

    Thank you so much for these tips! I’m so often baffled by the pepper section at the market that I won’t by any. My husband (a huge pepper fan) thanks you too!

  3. Katie

    Who knew that “stretch marks” could ever come in handy?? This info is extremely helpful because I’ve created some virtually inedible dishes due to really hot jalapenos. Now I’ll now to take a closer look at them. Thanks!!

  4. Andrea

    This is how my Husband’s cousin taught me how to tell the difference of Hotness in the Jalepeno’s. Very good visual example too.

  5. greyeagle

    How cool! I’ve never understood the heat issue.
    I’ve always just grabbed a pepper and then been mystified as to why there was either no heat or so much I couldn’t eat the dish. Thanks so very much!!

  6. celina

    I grow jalapenos on my balcony garden – should I leave them on the plant longer to make them hotter? Or is it only a post-picking transformation as you mentioned in an earlier comment? First time gardener!

    If you don’t pick them, they will eventually turn red. ~Elise

  7. Alexis

    Thank you! I actually remember thinking at the vegetable market, “why are they selling these jalepenos; they look old”. Now I know why!

  8. June

    Great tip Elise. Thanks very much. Picking peppers has always been such a “crap shoot”, it’ll be great to finally know what we’re getting.

    Oh, it will still be a crapshoot, just one with better odds. ~Elise

  9. Sara

    This is great for me, because I finally acknowledged that I really and truly loathe bell peppers in all colors, but I love a bit of spice to some of my meals. This way I can use jalapeños without fear!

    You should still fear jalapeños (wash hands carefully after cutting them, or wear gloves), and should always taste before using, so you know how much heat you are adding to a dish. ~Elise

  10. FoodieCrystal

    Thanks so much for this tip, I’ve always wondered why jalapenos had the lines in them (and silly me I’ve always avoided buying those because they looked inferior!)
    I just started following your blog yesterday and I’m looking forward to reading it (next week I will probably look through the archives.)

    FoodieCrystal

  11. Becks

    What a great tip! I was working with some jalapeños last night and they were so hot I got a chemical burn on my hands. I couldn’t figure out why they were so much hotter than usual!

  12. nikkipolani

    Ahah! I have wondered about that, but I have also found that if I don’t get anywhere near the seeds on the red ones, they have a little kick, but nothing that is too hot to handle.

  13. woody

    Good info on the jalapenos. Our local New Mexico chile is grown only for its individual hotness. It does not change its heat as it changes color from green to red.

  14. Sara

    One time I had the strongest burning sensation after touching peppers, so now I always wash with lemon juice after touching! It was the only thing that worked. Especially when pregnant…

  15. Sharon

    Thanks Elise! I grow jalapenos too and waited to pick so they would be bigger for stuffing and then couldn’t eat them due to be so overly hot.(They did have lots of stretch marks) Do you know if soil or growing temperatures makes a difference too? I’m in the midwest and we’re having a much cooler summer than normal.

    No idea on the soil or temperature. I suspect it has more to do with the variety, but who knows? Sometimes my peppers are all pretty hot, sometimes less so. Right now I’m growing some Anaheims that are completely mild. No heat whatsoever, but they taste great. I’ll buy what I think is the same variety starter from the same nursery and have different results based on the season. My tomatoes same thing. This year they aren’t nearly as flavorful as in past years. We had an exceptionally cool start to the summer and the local paper reported that the tomato crop was trailing by 4-6 weeks because of it. Tomatoes and peppers are related, so if heat affects tomatoes, maybe it affects chiles too? ~Elise

  16. Margaret

    I have to disagree with you. I grow jalapenos and can tell you that this is simply not true. Hotness is genetically determined: some of my plants produce mild peppers (no matter how old the pepper: green, stretched, or red, they are all the same). Other plants produce hotter peppers.

    Hmm. I grow jalapenos too, and have found otherwise. But it could be that the more mature peppers just have the capsaicin better distributed throughout the flesh. The variations in heat in the peppers from a single plant might be slight. I wouldn’t expect to have one plant that grew mild peppers and hot peppers, but I would expect the more mature peppers to be hotter than the less mature ones on the plant, at least in the part that I eat, the flesh. ~Elise

  17. Memoria

    First of all, I’m so glad to see someone spell “jalapeños” correctly!!

    Secondly, thanks for the tutorial about chiles. Your photos are lovely.

  18. Nicole

    Is it true that soaking the jalapenos in water for a bit reduces the hotness?

    Doubtful. What makes a chile hot is a chemical called capsaicin which is not water soluble, but is fat soluble. This is why drinking water after eating hot chilies will not help reduce the heat, but eating (full fat) yogurt or sour cream will. ~Elise

  19. Susan

    Thanks for the tip, I didn’t know about the white stripes, I just thought they were scratches! I was under the impression, based on green to red bell peppers, that the change to red makes them somewhat sweeter. Not necessarily less hot, but with more consentrated sugars in the maturing pepper it gets a lightly sweetened heat (not really sweet as we think of sweet). Like you advise, I always taste the peppers I chop to add to a dish, just to note how much heat is in the individual pepper. They do vary.

  20. Paul-Michael

    I have also grown jalapenos and I would agree with Elise. But one thing I have found out is that you can change the hotness of a pepper plant. If you grow hot ones next to mild peppers, they cross pollenate and the hot ones get milder and the mild peppers get a bit of bite to them.

  21. Chris

    I just read recently (maybe Gourmet magazine?) that it’s a myth that there’s any heat in the seeds, it’s all in the “ribs”.

    Yeah, just think about that myth the next time you eat a seed. Hah! ~Elise

  22. Susan at SGCC

    How interesting! I’ve also had my share of “dud” jalapenos. I’m going to try this strategy the next time I buy them.

  23. Beth

    Great post – I love to cook with fresh peppers, but when I first started out the results were unpredictable. One time I’d make a dish with 2 jalepenos and it would turn out great. Other times, it would be turn out so mild it would have no heat at all or almost be inedible!

    I started guaging the heat of the peppers by smell. You can cut it in half and get a good idea of the heat of that pepper and adjust the amount you put in accordingly.

    I had never heard your suggestion about the striations, but it makes sense!

  24. Dave

    A few years ago I grew some jalapenos in a pot on the front porch. Occasionally, they dried out, but then got watered a couple days later. They were the HOTTEST jalapenos I have ever had from any source. I think I read somewhere that the amount of capsaicin in a particular pepper is connected to the amount of stress that the plant went through. I also let them get completely ripe (red and striated). This year I have 4 plants and about 10 peppers so far, but if not for all the rain, I would have more in production. I’ll let you know how hot they are.

    Dave

  25. Seamus

    I’ll look forward to checking this out. In one of my Mexican cookbooks, there is also the claim that heat is related to the size of the “shoulder” of the pepper, the part just under the stem. Supposedly, the narrower the shoulder, the hotter the pepper. I often employ that when I buy, but it’s hard to know how accurate it is.

  26. Walter Underwood

    Even with this tip, peppers are quite variable. Always taste before using. Last week, I bought two poblanos and one was very mild while the other was fairly hot. I know because I tasted them.

    A bit more info from Jean Andrews’ lovely book “Peppers” — the ribs have about double the concentration of capsaicin as the outer wall and bleach or milk will remove capsaicin from your hands. It is also soluable in alcohol.

    Personally, I always use serranos instead of jalepenos. They just taste better.

  27. Ari

    Thanks Elise… although I live in Mexico and have known jalapeños all my life, this is very useful. Especially now… all the chiles that they serve in restaurants here in Monterrey nowadays are SO hot!! horribly so! I myself am not a chile fan, but I do enjoy some spice now and again. So, I will take your advice into account. Do you know if the same holds true for chiles serranos (or chiles verdes, as they are commonly referred to)?

    I don’t. I have not seen serrano chiles develop the same striations, though they will turn black-ish on their way to turning red. ~Elise

  28. Dean E.

    Thanks for the enjoyable tip and great photos. I’ve noticed that some of my local markets (not the Latin tiendas, but stores like Safeway) carry a different brand of chili that they call “red jalapeños” except that they don’t appear to be jalapeños at all unless there is a variety that I’m unaware of. Do you happen to know if this is a misnomer or if it is a different variety with the same common name? The principle difference is at the stem, which isn’t as round as on “green” jalapeños. They aren’t just the usual sort of jalapeños that have turned red on the shelf.

    Haven’t heard of it. ~Elise

  29. Amy Scott

    Great article! In Texas, they call the striations “heat marks” and the more you have indeed the hotter the pepper. The color is not necessarily a good heat indicator though as it depends on if the pepper ripened that way on the vine or off. If the pepper is allowed to ripen on the vine, it will be hotter and a bit sweeter. I have also have had store bought red jalepenos that were mild, so really the heat marks are the best way to tell. Also another way is by the weight of the pepper – if it’s heavier than it looks, it will be hotter.

  30. Lydia

    I, too, have to disagree on some level. While I have never really tested the proposed “tip” I do know for certain that some of the mildest jalapenos I have ever had were the red ones (they are SWEETER, and sometimes hotter, but not alwasy). I’ve never really paid attention to the striations. Here in the Southwest, we have chiles everywhere and several of the farmers that I’ve talked to indicate that the real factors that influence heat in any kind of chile (that would be degree of heat within species of course) have to do with growing conditions, primarily water. The chiles on the outer edges of the fields where it is hotter and drier are the hottest of the harvest and vice versa. Many vendors (in market stalls as well as supermarkets) would be glad to offer you a sample of the produce. I always just test the stem end after I remove it from the chiles to see how “hot” they are going to be.

    Also, regarding the person who commented above wondering about “red” jalapenos being true jalapenos, I can only assume that they are in fact jalapenos that are more mature (thus red). The lack of “roundness” in the stem is likely due to the fact that it is somewhat more dessicated than the green counterparts due to its age. That said, it wouldn’t be the first time produce was mis-named or mis-labeled.

  31. Luana

    What great information! I really do like the red ones the best; somehow the sweetness of them does not make them seem as hot to me as the green.

  32. Bridget Sutton

    The best way is to grow your own. Buy one and grow from the seeds inside. It´s great fun and you can try them from green to red. I grow them on the balcony in Spain and the window sill in England and have been sucsessful. I keep the crop for future use in sterilised jars chopped and covered with virgin olive oil. Good luck!

  33. Marc @ NoRecipes

    I’ve had the same problem with jalepenos, that’s why I just steer clear of them altogether and user Serrano chiles which tend to be more predictably spicy. We have these chilies at Indian groceries here in NY that tip the scale at 1M scoville units (about 200x more capsaicin than Jalepenos)

  34. Kris

    This is not completely accurate. The striations do imply a hotter pepper, but if you allow the pepper to ripen to the point where it’s red it will lose some heat and get sweeter (though it will likely still be hotter than before the striations).

    If you’re growing peppers the striations are a good indication of when to harvest, though not all pepper varieties have them.

  35. Chris

    This is a reply for Margaret from the Midwest. My father has gardened for over 60 years and he always said the temperature and the soil does play part in the heat of vegetables. I have never grown jalapenos but he has grown thousands in his time as a gardener. I know that the soil and temperature does come into play on a lot of other vegetables.

  36. Shannon

    I heard somewhere that you can tell the hotness of a chili by how curved the stem is. The more curve, the more heat. It’s been pretty true for me – but it could also be because the more mature peppers have more curved stems.

  37. Bill Huey

    There are many sub varieties of jalapeños. New Mexico State University is researching chile agriculture along with several other Universities in the Southwest. In general, length to width is a good gauge of general expected hotness for all chilies (with the exception of Habenero and Scotch Bonnet), the longer and thinner the hotter the chile will be. Age of the chile will affect the hotness to some extent, but not as much as the genetics, and the environment that it was grown in and the weather during the time it was ripening.

  38. Tracy

    I buy serranos because they seem consistently hotter than jalapenos. And they’re the same price at grocery stores. Also jalapenos taste “green” to me, like how green bell peppers taste in comparison to red or orange ones. Serranos don’t have that “green” taste.

  39. David

    Actually, the seeds don’t really contribute anything, but since the seeds are attached to the ribs, that’s the source of the myth that the seeds have more heat. It’s actually the ribs conferring the heat, but the seeds got the blame. They’re just coated in the capsaicin from the ribs.

  40. nlwreeds

    Many years ago we found out that there is a great way to control the heat of your peppers if you are growing your own.

    For mild peppers: water regularly, neve let them get too dry. Happy peppers seem to grow up much to be much milder in heat.

    For HOT peppers: abuse your pepper plants. Wait until they are wilted to water them, don’t let them die (no way to bring them bck from the grave), but abuse the plants. It just seems to make the peppers mean.

    Also, for all varieties of peppers (including bell peppers) they are really ripe when they are red. Peppers picked green are immature.

    Enjoy.

  41. Bryan

    I’ve heard that this is a bit of an old wives tale. There is no capsaicin in the skin, only in the membrane that connects the seed to the ribs. The stirations are from stress and age and can be an indication of heat, but they do not signify heat alone.

    Me thinks that the milder strains are simply becoming more common with supply chains, but thats just a theory.

  42. ted

    The soil in which the chile is grown is pre-eminent. If you want really hot chiles then grow them hydroponically. That in itself will increase the capsacin by about 10 fold in what ever chile you decide to grow.

  43. Chef Kt

    I planted a purple jalapeño plant this summer and have been *thrilled* with the purple peppers that it’s producing! So hot that your skin tingles if you rub it after having chopped the pepper…. (Saving these seeds for sure!)

  44. Robert

    Actually what makes a pepper hotter has been studied. Capsaicin is produced by the plant in defense of either bugs, animals or mold. So if you want your peppers to be hotter plant them and mist them with water in the evenings.

    Now birds are not effected by capsaicin so they can eat the peppers and then disperse the seeds else ware..

  45. Brandon

    From a paper on Padrón Chili peppers: Capsaicinoids were detected 14 days after flowering in the first stage. Their levels remained low for 21 days, but 28 days after flowering capsaicinoids increased moderately, and finally, at the end of development, the cv. Padrón pepper exhibited a dramatic increase in capsaicinoid levels with the highest values found in the fifth stage, 42 days after flowering. The level of capsacinoids in the cultivar Padrón was lower than that in other fruit varieties (Iwai et al., 1979; Salgado-Garciglia & Ochoa-Alejo, 1990). -Estrada et al. 2000, J. Agric Food Chem.

    It’s not Jalapeño, but the fact that 4 other cultivars had similar capsaicinoid production patterns suggests that they do get hotter towards maturation.

    The striations that you photographed are actually cracks in the skin of the fruit that develop when there is excess root pressure to where the skin cannot push back. Usually fruit (of any kind) are more susceptible to this sort of cracking when they are more mature (Tomatoes, melons, etc…). As the fruit expands and matures, the skin is stretched thinner and thinner and the fruit wall begins to soften and together cannot push back against the pressure from the roots. Tiny fractures occur in the skin to relieve the pressure which then become suberized and more visible.

    If anything, the fractures indicate maturity, which does appear to correlate with increased capsaicinoid content.

    Also, as many people mentioned, there is strong evidence in the literature that increased stress on the plant will induced increased production of capsaicinoids. Letting them wilt, flooding the roots, handling the plants, increased soil temperatures, and increased air temperatures will all stress out the plant more and cause increased production.

    Your method may not be perfect Elise, but there is scientific precedence to back of some of your ideas.

  46. Shirley

    My husband was buying jalapenos to add to a pot of pinto beans. He noticed an elderly man choosing the ones with the most striations. Hubby asked why and the gentleman told him the more striations the hotter the pepper. My husband used that method and put the usual amount in the beans. The beans were about triple the heat than normal. We couldn’t eat them. We regularly eat very hot and spicy food. Word to the wise…in cooking use less of the striated peppers.

  47. Akila

    Elise, this is a wonderful tip. And, based on Brandon’s research, it looks like this would apply to poblano peppers as well. Thanks Brandon for doing that research!

  48. Sharon

    O.K. The proof is definitely in the pepper. I have now picked and ate (yeah) younger, smaller peppers that were on the same plant that produced the heavily marked peppers that were too hot to eat before. Same soil, same growing conditions. I am so happy to have this knowledge now! I will be picking sooner and be able to judge purchased peppers so much better now. Thank you so much again Elise!

  49. Kristina @ Trivial Bliss

    Thanks for this, I used to wonder about the striations. This summer we have our own peppers, chili and jalapeno plants in the garden and I have a (I guess stupid) question. On one plant we have red and green ones, some are just green, will they all turn red after green? We never tried it before because we thought that you can’t grow them in Germany because our summers aren’t long and hot. It does work though and we’re really proud.

    Yes, they will all turn red if you leave them on the plant long enough. ~Elise

  50. courtney

    Well, it’s worth a try since I always pick the ones that look the “freshest” and am disappointed that there is no heat.

  51. Katie

    Hello – I have chopped some jalapenos (without gloves) and have washed my hands several times however my fingers are still “spicy”. Is there a way to get rid of that. I have a new baby and do not want to transfer that over to his skin. Thanks!

    Good question. The spiciness in jalapenos comes from a chemical that is oil based, so you might try rubbing your hands with an oil-based lotion, or even vegetable oil. ~Elise

  52. love2bbitten

    Like Alexis, I too wondered why my grocer always sells wrinkled old looking chiles (I use serranos rather than jalapenos, which are hotter to begin with). Very interesting… I usually get some pretty hot serranos, and I always pick the prettiest smoothest ones… I guess I still won’t be going for the wrinkled ones! Cool tip though;o)

  53. april

    An older Mexican man in a grocery store told me about striations way back in the day. I was forever grateful!

    For Katie: rubbing your hands in salt will take care of the heat. It’s a trick I stumbled on (I figured if it works to cool down hot salsa on chips–by sprinkling salt on the chips–it might work on hands!). The saline (salty water) solution destroys heat.

  54. mike

    Thanks for the article. I’ve read that the striations are also called corking.

    I found this article in an attempt to figure out why my homegrown (actually my office grown) peppers aren’t so hot anymore. I’ve had my plants for three summers, having grown them from seeds in a window box in a south facing window (important in Alaska!) Even the heavily corked red peppers have next to no heat. As the plants have aged, the heat level seems to be more and more dependent on sunlight, though there is an occasional hot one.

  55. Martin

    Brilliant answer, best on the net (most others seem to use it as an excuse to rant about mildness being bred into the chillis) because it is so practicable and with good images. And I am going to see if the Cayenne and Bulgarian Carrot Chillis I am growing follow the same guidelines. Thanks Elise

  56. Lulu

    Awesome tip. Thank you!
    I always look for the smoothest, most perfect looking jalapenos when I buy them. Maybe this is why I have never purchased a truly hot jalapeno. I like the flavor of them, but I have always considered jalapenos ridiculously mild.
    I’m going to try this method.

  57. Bob

    Growing Jalapeno peppers! I have 2 plants growing right now. They have been shaded by the tomato plants next to them. Several of the fruits are turning bright red. Cowabunga! Here they come! Let’s see how hot they are. Yummm!!!!!!

  58. Leona M

    It has been my garden experience that a stressed plant puts out a hot pepper. It makes sense. stressed plants are protecting themselves from being eaten. They make more capsaicin. Also its the fleshy veins inside that are hot. I always take a tiny bite of each one, then add more or less of them as the case may be. HTH

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