How Can You Tell If Your Jalapeno Pepper Is Going to Be Hot

April 30, 2012 31 Comments

How Can You Tell If Your Jalapeno Pepper Is Going to Be Hot

How Hot Is That Pepper?

My friend Paula has been teaching me some basics of Mexican cooking and one of the ingredients she loves working with are jalapeno chili peppers. In fact, as a snack, she likes to slice them up and eat them with a little salt and fresh lemon juice like they were Bonbons. I try a piece and I end up with the hiccups.

Last week we were working on a fresh tomatillo salsa that Paula has made for me in the past and is now a staple in my fridge. It is so versatile. You can put it on just about anything you want to spice up with a little flavor like roast chicken, fish, pork tenderloin. This sauce is perfect for tacos, tamales, and tortillas or as a simple dip for corn chips.

Here’s the recipe for tomatillo salsa.

Look for Hotness

Just a few ingredients in Paula’s tomatillo salsa and one of them is the jalapeno pepper.  I noticed one week we added six jalapenos peppers to one pound of tomatillos and the next week just two jalapenos. I asked why and she said the two jalapeno peppers were much hotter than the six other ones.

Of course I asked her how she could tell without cutting open the peppers and tasting them. She told me she does it by looking at them. It seems that jalapeno peppers get hotter as they get older and the older they get, they change in appearance.

When young, they are smooth, uniformly green and less hot but as they get older they start to develop striations or lines in the outer skin. You’ll also start seeing little white lines and white flecks in the skin as shown in the photo above.

According to Paula, these should be hotter and sure enough the version of tomatillo salsa made with these two older jalapeno±os was hotter than the batch we made with six.

Does that mean you can’t find really hot jalapenos with smooth skins? I don’t think so. I’m sure there are some jalapeno±o peppers that are perfectly smooth that are really hot but just imagine how hot they are going to be when they age some. Supposedly red jalapeno±o peppers are at their ripest and most hot. I stay away from them so I have no idea.

Hotter In Refrigerator?

When I asked Paula if the peppers gets hotter with age in the refrigerator, she said they do. I’m not a food scientist but I did purchase a few jalapeno peppers and watched them over the course of a couple weeks and can say yes, they do develop the white lines and striations as they age and yes, they were much hotter.

Don’t take my word for it. If you like hot, spicy foods try this experiment for yourself and see what results you get. I would love to hear about what you find out.

And when shopping, you now can pay attention to the bin full of jalapeno peppers and have a better chance of picking out the hot ones if that’s your goal.


Last modified on Tue 15 January 2019 2:22 pm

Comments (31)

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  1. Cathleen says:

    Thanks for this info!! I have always passed up the older looking ones for the smooth shiny fresh picked pepper and was disappointed at how little heat they do have if any. Older ones left behind no more!

  2. susanne says:

    Yes. thanks so much for the info. Thank u for sharing your knowledge. It is greatly appreciated!!

  3. Jeff says:

    For those that grow their own chiles. The heat of the pepper is largely determined by soil moisture. As the soil dries, the chiles release capsaicin as a defense mechanism. So, if you want hotter chiles, go easier on the watering and let the soil dry. If it’s a wet spring our early peppers are always mild. I like to let the ground dry up quite a bit to the point of nearly wilting the plants.

  4. Diana says:

    Wow . . . thank you this is all great information to learn… I have been making my own salsa for years and have grown peppers a few times but never knew any of this information!

  5. Carolyn says:

    With the goal of making lots of salsa this summer, I’ve planted numerous types of peppers. Not only will I keep my eye out for the striations, but I love the comment about soil moisture as it relates to the heat of the pepper. Looking forward to the tomatillo recipe later this week as well, as I’m growing those for the first time.

  6. Georgia says:

    When I was in a Mexican supermarket, I asked a Spanish Speaking produce man how to choose jalepenos that are less hot. He told me that the peppers with a wilted or browned stem are the hottest. So, choose the ones with a nice crisp green stem for those less hot.

  7. Todd says:

    My personal experience says putting jalapeno’s in the fridge will NOT make them more hot. In fact, I’ve found quite the opposite to be true. If you want to make them less hot, put them in the fridge. Not the other way around like this article says. While the state of the outside may be a good indicator as to heat, putting them in the fridge certainly does NOT make them more hot. It’s sad that I have to disagree with someone who has worked with these peppers for such a long time. You’d think that experience would lend some credibility to what they ‘say.’

    It’s logical. The longer you store/freeze something in the cold, the quality/taste/what have you, just degrades over time. The same happens with the heat of the jalapeno pepper. Sorry to burst your bubble.

    Granted I don’t keep jalapeno peppers in my fridge for ‘weeks’ like in the article. That’s just another odd thing about this. They don’t even last that long in the fridge, let alone outside of it. Where is this info coming from? The only thing that lasts ‘weeks’ in my fridge are things like ketchup and other jarred items/condiments.

    Todd, it may be your experience that jalapeno peppers don’t last in the refrigerator but I some in mine right now that are three weeks old and they are perfectly fine, have more striations than they did two weeks ago and they are definitely hotter. I’m not a food scientist so this is totally anecdotal but I would request before you make statements like those above, you at LEAST give it a try for yourself. – RG

    • NMBob says:

      I just made some poppers with jalapenos that had been in the frig a long time, some of them too long and threw them away…..mildest jalapeno poppers i have ever made. So I have have experienced what todd says. But this is definitely a couple weeks in the frig, not days.

    • Gina says:

      Todd, when I read it that is not how I took the comments. I understood it as a question to will they still continue to get hot in the fridge. The answer is yes. It may preserve them longer maybe even slow down the process of heating up but no one said that basically a fridge is going to make them hotter than being at room temp. That was your assumption. It was cocky and condescending and very unnecessary. It was not constructive whatsoever. Plenty of people by jalapenos and end up not using them like they thought they would. I have grown jalapenos many years and guarantee that I have left them in the fridge for 3 weeks.

      • Jim says:

        Paula did in fact say they got hotter when put in the fridge. So maybe you (Gina)should read the article over again before making your own comments.

        Just saying.

  8. Carol says:

    I have not found this to be true. I buy jalapeños that are smooth and green with crisp stems at the same grocery and sometimes the are nice and mild (I prefer them like that) and sometimes they are too hot for me to enjoy. I wish I understood how to buy the ones I like.

    • Gina says:

      Carol, this is just one indicator that they are mentioning. If a guilty of anything it’s not giving complete information. Any jalapeno can vary based on its origin. Go to any nursery and look at a selection of jalapeno pepper plants. They will have mild they will have moderate hot and so forth. That is only the base flavor. Each jalapeno individually can become more intense as it ripens

  9. Chris says:

    I’ve been growing Jalapeno(and other) peppers for 5 years. There are a wide variety of Jalapenos. The variety really plays a big role. Personally, I prefer the Billy Biker for a good heat. If you are not growing them yourself, then you won’t really know.

    The striations referred to are called corking. Corking is caused by the pepper growing faster than the skin can keep up. The skin rips and the heals leaving a small scar. But I do use it as a measure of when to pick the peppers. Picking too early does not give time for the capsaicin to develop.

    Peppers keep longer on the bush than after picked. But the more you pick, the more peppers your plants will produce. If you leave them on the bush they will eventually turn red. The red ones, in my experience, do not have the same flavor as the green and I have not noticed them being any hotter really. If anything they get sweater and less hot when the turn red.

    Remember that the Scoville Scale measures how much sugar solution is needed to dilute the capsaicin until it is no longer hot. Plants produce sugar via photosynthesis, hence after certain point, the sugars start to collect in the pepper and neutralize the capsaicin resulting in a sweater and milder pepper.

    Now, to further confuse you. After a pepper is picked, it can still turn red as it ages and dries. This is usually a deeper red than you get when they redden on the bush. When died from green to red, they maintain their heat and flavor, and may even get a bit hotter. This is useful, if like me, you like to dried and grind them for use in cooking.

  10. Natasha says:

    I love making poppers and I have noticed that it is true that the jalapeños get incredibly hotter as they age in the fridge. I am not weak when it comes to spicy food, yet when I leave them in the fridge a couple weeks…yikes! I can hardly take it…fire and tears, but delicious flavor!

  11. Christine says:

    Great info I’m growing Jalepino peppers for the first time in pots on my patio,there comming on rally well at the moment,my son likes really Hot peppers ,he picked one today to try it but not hot at all(there only very young yet)so it’s great to know the longer you leave them the hotter they get:-) and the soil tip excellent Ty so much,carnt wait for your Salsa Recipe !

  12. MARCO says:

    I am filipino born in southern tagalog of the philippines (the bicol region) where we are famous on the “siling labuyo” suppose to be the the hottest pepper in the world but was changed by the guinness book of record. I tasted the habanero and I am not impressed. Anyway, back to the jalapeno I prefer the serrano chile. And according to our Parish Priest Fr Gallegos (an american born/mexican priest) when you grow your peppers you have to starve your pepper. It is true that when your soil is moist you are probably over watering your plant (pepper).

  13. Ted says:

    I grow peppers of different varieties. Fresh green and red jalapenos I freeze whole in gal. bags. Over time they do get hotter. I make fresh salsa every week with the jalapenos. The freshest ones I use 5 per two quarts. After four months I get down to 1 per two quarts, that’s how much hotter they get.

  14. Yvette says:

    I have a jalapeno plant in my garden for the first time this year. I couldn’t figure out why some were very mild and others were overly hot. Your article has helped a lot. Thank you.

  15. Julia says:

    My friend, Jose, told me that Jalapeno peppers will be hotter-the darker they are.
    Jose said to rub the skin of the pepper-if the skin turns darker (almost black) that it will be hot. I tried his information and it actually worked for me. I buy the darkest green shiny ones in the store and have never got a mild one.

  16. Britt421 says:

    Parts of each comment hold some truth . But too get the best out of your peppers depends on how you feed those plants no matter what varity.they do a lot of work and the bigger they become the more you need to feralize.I grew some that were Perty hot and after picking the first few mature peppers (the ones with the serations). I applied some cow manure compost 6 inches away from the main stalks out past the drip line and gently worked into the soil.when the next batch of peppers were mature and ready to pick they were the hottest and most flavorful jalapenos that I have ever eaten.A higher phosphate fertilizer like for tomatoes works well with an occasional application of blood meal. (Jobes Organics) worked very well.

  17. Roberto says:

    Apparently, jalapeño peppers DO get hotter while aging in the fridge. I just googled “Do peppers get hotter in the fridge?” I did not believe it was true but had no other explanation occur to me as to why the jalapeño cheese muffins I make regularly were suddenly so hot yesterday, no one in the family could eat them. The only difference was that I forgot the peppers in the back of the fridge. I don’t know how long they were back there but it could have been a month, in a Baggie. They had some grey spots in them and they had turned a dark green color. Well I cut the gray spots off(I know gross huh) and used two of them in the muffins which then blew our heads off. Hence the googled question, and the answer.

    • Thanks Roberto for confirming what I mentioned in my post. We just made to tomatillo sauce last week and used some jalapeno peppers that had been in the refrigerator for just two weeks and the sauce was “almost” too hot to eat. Gave me the hiccups.

  18. kyle says:

    i wondered why the jalapenos i have in my fridge were such ass kickers but yeah theyre loaded with pits and lines things are almost as hot as a weak habanero

  19. Ralph Emigh says:

    If you find your peppers are to hot just remove the seeds and membrane.

  20. Payten L says:

    I looked for the salsa recipe, couldn’t find it! Was really hopin to find a good one with the right amount of spice /:

  21. Ben Kooi says:

    Dear R.G,
    Just read this article. Very informative and most enjoyable! Learned some new thing along the way I was not fully aware off. (The effect of a fridge and water amount)
    I think I will return to your site again (it’s in my favorite list now).
    Growing a variety of over 25 pepper species in Amsterdam. Might you ever get lost in my region feel free to contact an pick up some tasty peppers.

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