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Jan 21, 2008 01:13 PM

How do you determine a jalapeño's heat?

I'm stumped. I really love HOT jalapeños, and only about 1 in 3 has any heat. I thought this variance is due to some wayward genetic engineer who decided the world needed a mild jalapeño, but a chef friend told me that the heat of a jalapeño has to develop before the jalapeño is harvested, and that red jalapeños (which I've very rarely seen in NYC) are in fact all hot.

Want to weigh in on either theory? Only one of them can be true.

And how do you figure out how hot a jalapeño is going to be without opening it up? Another chef told me that the pointier the tip is, the hotter the pepper, but that has not turned out to be true.

Help me ratchet up the heat!


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  1. Jalapenos are indeed milder than they once were. The only way to know if it's hot is to taste it. Do not cut out the ribs and seeds if you are looking for some heat. In general smaller peppers are hotter and the thing about the red jalapenos being hotter is true. If you like jalapenos you should try serranos. They are easy to find, have a more fruity pepper taste and have more heat than the jalapeno. They are smaller and more slender and are my pepper of choice for most dishes that suggest jalapenos.

    1 Reply
    1. re: scubadoo97

      I'll try buying smaller jalapeños. Yesterday I had a serrano chile that had NO heat whatsoever. So strange.

    2. I think in general, for hot peppers, the smaller the pepper the hotter it is. I dont think this is true for one type of pepper like comparing one jalapeno to the next but is about chile peppers in general, i.e., jalapeno compared to a serrano compared to a habanero.

      In NYC, the only really hot jalapenos I've found have been from the union Sq. greenmarket during the summer from the vendor right across from barnes and noble. All supermarket ones I have tried have been slightly hotter than bell peppers. I was once told that if you scratch and then sniff a jalapeno you can tell how hot they are but i'm not sure thats true. I've also been told that the hotter the growing climate the spicier the pepper, so maybe you just have to wait till the summer again...

      8 Replies
      1. re: ESNY

        Again, I'll try smaller jalapeños. I think you're right, it may be a seasonal issue, although I have had jalapeños in winter that were hot. They must have been from warm climates. The only grocery store in my area (Union Square) that tells you the origins of their produce is the enlightened Whole Foods.

        The Greenmarket farm you're referring to is Blew Farms, and their jalapeños are indeed hot, but they also sell "mild" jalapeños. I'll have to ask Farmer Blew how he grows each variety.

        1. re: Tom Steele

          P.S. When pepper season peaks, toward the end of summer, Eckerton Farms comes into the market. Farmer Tim Stark grows the best, cheapest, and largest variety of peppers of anyone in the market. This year I discovered how well certain small hot peppers freeze, so I've been enjoying them all winter.

          1. re: Tom Steele

            I love Blew Farms. Last year I stuffed some of his Hot Hungarian Wax peppers with italian sausage, breadcrumbs and romano cheese, baked till cooked through and it almost blew my mouth apart.

          2. re: ESNY

            I don't buy into your 'smaller is hotter' theroy. It just doesn't hold. When I buy my favorite brand of canned pickled jalapenos the bigger ones tend to be just as hot as the smaller ones. I don't think there is any way when buying fresh jalapenos from the produce section at the market how to tell or determine which ones will be the hottest other than you'll finding out when you eat them. I would tend to be more in agreement with 'foodnerds' who grows his own in that leaving them on the plant longer helps to develop their heat. And as another said, ..."region, climate, growing conditions," are also a factor that can determine level of heat.

            1. re: crt

              "I don't buy into your 'smaller is hotter' theroy." It is an accurate general guide, but only when comparing different types of peppers, not different peppers of the same type. The size of one jalapeño is no indication of its heat compared to another jalapeño.

              On the whole though, while there are some exceptions, bigger peppers tend to be milder (think bell peppers or Italian peppers), while many of the hottest are among the smallest (like bird's eye, datil, or piquins). It's not an absolute rule - habañeros stand out as an exception - but it is a useful rule of thumb to keep in mind when encountering peppers of an unfamiliar variety and unknown heat level.

              1. re: crt

                The 'smaller the hotter' rule of thumb applies best across varieties, not within a variety. Thus a serrano is hotter than a jalapeno which is hotter than a poblano. But a rocoto is hotter than a serano, but generally larger. Don't expect a small jalapeno to be hotter than a large jalapeno.

                So if you want something that is meaty like a jalapeno, but hotter, try serranos. Rocoto is also meaty, but harder to find.


                1. re: crt

                  Another thing to note is that in canned or jarred peppers the heat from the "hot" peppers will disperse somewhat throughout the batch during processing and so evening out the heat level of all the peppers.

                  1. re: crt

                    Perhaps I didn't write clearly enough, what I meant was that across varieties of chile peppers, the smaller the pepper, typically the hotter it is. I.e., Cubanelle vs. Jalapeno vs Serrano vs. Thai bird. I agree that when referring to a specific type of pepper, like a jalapeno the size does not matter.

                2. Chili peppers have differing tastes, levels of heat, and personalities, even from the same plant. Poblanos and jalapenos have amazing ranges, and the only way to know is to taste. Habanero and serrano I rarely use, because even the low end of their range is nuclear, and it's not worth the while, save for a couple habanero sauces I use sparingly.
                  Buy more jalapenos than you think you will need. Learn to measure their heat from a taste from a slender slice. Use the mild among them to fill with cheese or shrimp and deep fry them, with or without a beer batter. Use the hot ones judiciously.
                  "Red" jalapenos are simply ripened longer on the plant, beyond the customary harvest point. Rest assured that scientists are not engineering your favorite pepper into the history books; hot jalapenos remain as ubiquitous as rattlesnakes.

                  6 Replies
                  1. re: Veggo

                    Scientists are engineering our favorite pepper. Several years ago, Dr. Ben Villalon, Texas A&M Plant Pathologist and Pepper Breeder created a mild jalapeno.

                    1. re: jackrugby

                      That can be useful. The cheese or shrimp-stuffed jalapenos I reference in my post above, using the mildest of the lot, are often still too hot for the common person. And they are such a wonderful size for appetizer concoctions.

                      1. re: jackrugby

                        I *thought* so! And to my palate, mild jalapeños don't taste appreciably different from green bell peppers! What a fool Villalon must be.

                        1. re: Tom Steele

                          I think it serves a useful purpose to those who enjoy the basic flavor but have difficulty with the heat. We all have different heat-pleasure-pain coefficients. Clear labeling of the "modified" and the "natural" would enable more of us to enjoy them.

                          1. re: Veggo

                            I've read about the mild jalapenos, but I wonder whether those appear in regular groceries. Seems that they were developed for large salsa companies (like Pace) that wanted to control their heat of their products. They can use mild jalapenos to provide the body and chrunch, and add heat (possibly in the form of an extract) to specification. If that is the case, most of the mild crop is grown under contract for companies like this.

                            If the jalapenos in your regular grocery seem too mild, then either try a hotter variety like serrano, or try jalapenos from a store with a larger Hispanic clientèle. They might get more complaints if a distributer ships unusually mild ones.


                        2. re: jackrugby

                          I would guess that the peppers are simple selections and/or crosses that you could do in your own garden. Genetic engineering is still costly and is not used where simple, traditional breeding will do.

                      2. I use jalapenos as an 'everyday' pepper, meaning I put them in just about anything. To me they aren't very hot. When I want more heat, I'll mix in other peppers. For chili, it's often two jalapenos and one habenero. Or four to five serranos. I also love chipotle in adobo, sometimes straight out of the can. It all depends on what looks good in the store that day. Mix your peppers up and you'll get both heat and flavor. And don't ever throw away the seeds that carry so much flavor. That's just criminal.

                        3 Replies
                        1. re: mojoeater

                          The only time I discard jalapeño seeds is when I'm making room for stuffing. The real heat is in the "ribs"--the white membranes that run vertically inside the pepper. I love chipotles too. They're reliably hot. The processors must know how to select hot jalapeños--and come to think of it, they're all small!

                          1. re: Tom Steele

                            There are two kinds of chipotle peppers. One is a smoked green jalepeno and the other is a smoked red jalapeno which is smaller and called a morita. That is what I usually buy dried when I make my own chipotle in adobo.

                            1. re: scubadoo97

                              I didn't know that. But most of the dried and especially canned chipotles I've seen have been pretty small, so they must mostly be red jalapeños.

                        2. Chile peppers are an amazingly complex product. Jalapenos will develop more heat if they are grown under stress. The region, climate, growing conditions, time of harvest all have an impact on the heat. I agree with the other posters who say the only real test is to taste them. A Peruvian chef friend told me once that jalapenos which have little whitish striations on the skin are hotter than those with a uniform green skin. I have found that roasting jalapenos (like you would sweet peppers) intensifies the heat quite a bit.

                          3 Replies
                          1. re: JockY

                            America's test kitchen did a report on the hotness of Jalapeños and they found that there was no way of visually telling how hot a pepper would be. They mentioned that growing conditions were the cause of the level of heat. If the plant encountered more harsh conditions it would be hotter so perhaps the whitish striations on the skin are due to strain on the plant?

                            1. re: JockY

                              I never thought of selecting peppers with white striations! Interesting! I'll try some today.

                              1. re: Tom Steele

                                Toward the end of the season, when nights are cold, my peppers get almost black streaks and striations, and they're less hot. (I buy a bunch of reliably hot jalapenos in early fall and freeze them.)