How Hot Is That Pepper?
Ever bite into a jalapeño thinking it would be mild, only to get hit with serious heat? Yeah, we’ve all been there. Jalapeños are sneaky. Some are mellow and grassy, others bring the fire. But how can you tell the difference before taking that first bite? Good news—there are a few simple ways to spot a spicy one.
In this post, I’ll walk you through some easy clues that hint at heat level. We’ll look at the outside of the pepper—its size, color, and those little stretch marks called “corking.” You’ll learn why some peppers pack more punch than others, and what influences their heat.
No need for guesswork or surprises. Once you know what to look for, you can pick the right pepper every time—whether you want to dial it up or keep things tame. So next time you’re slicing up jalapeños for salsa, nachos, or stuffing, you’ll know exactly what kind of heat you’re working with.
Let’s get into it and take the mystery out of the jalapeño.
Ways to Tell If a Jalapeno Pepper Will Be Hot
| Sign | Description | What It Means |
|---|---|---|
| Corking (white stretch marks) | Small tan or white lines running down the skin | Usually a sign of higher heat and maturity |
| Smaller Size | Shorter, thinner peppers | Often hotter than larger ones |
| Darker Green or Red Color | Deep green or red instead of pale green | Indicates ripeness and more developed heat |
| Firm Texture | Feels dense and firm to the touch | Can be a sign of higher capsaicin content |
| Tip Shape | Peppers with a pointed tip | Sometimes spicier than blunt-tipped ones |
| Stem and Seed Smell | Sharp, pungent aroma when cut open | Can indicate a spicier pepper |
Look for Hotness
Just a few ingredients in my tomatillo salsa, and one of them is the jalapeno pepper. One week, I added six jalapeno peppers to one pound of tomatillos, and the following week, I added just two jalapenos. The reason, two jalapeno peppers were much hotter than the six others.
You can tell by looking at them, feeling their texture and giving them a smell. Additionally, jalapeno peppers become hotter as they age, and their appearance also changes.
When young, they are smooth, uniformly green, and less hot, but as they age, they start to develop striations or lines in the outer skin. You’ll also start seeing little white lines and white flecks on the skin.
These should be hotter, and sure enough, the version of tomatillo salsa made with these two older jalapenos was hotter than the batch I made with six.
Hotter In the Refrigerator?
Jalapeños actually can get hotter as they age in the refrigerator, and here’s why. When a jalapeño is freshly picked, its capsaicin—the compound that makes it spicy—is at a certain level. But over time, even in cold storage, the pepper continues to ripen slowly. This ripening process can cause the capsaicin concentration to increase, making the pepper taste hotter.
Also, as the pepper ages, it loses moisture. When water content drops, the capsaicin becomes more concentrated in the pepper’s flesh. Think of it like reducing a sauce—the flavors (and heat) get stronger as the volume shrinks.
Another factor is that cold slows down, but doesn’t completely stop, the pepper’s natural chemical changes. So while refrigeration keeps jalapeños fresh longer, some chemical activity still happens, gradually boosting their heat.
In short: older jalapeños in the fridge can feel spicier because they get more concentrated and mature, even though they might look a little wrinkled or softer. So if you want milder peppers, it’s best to use them fresh!
Jalapeno Temperature Range
Jalapeño peppers typically range in heat from about 2,500 to 8,000 Scoville Heat Units (SHU).
On the low end, milder jalapeños score around 2,500 SHU, which is just a gentle kick.
On the hotter end, some jalapeños can reach up to 8,000 SHU, delivering a noticeable burn.
This range depends on factors like growing conditions, ripeness, and even the specific jalapeño variety. So, when you bite into one, it could be pretty mild or surprisingly spicy!
| Jalapeño Variety | Description | Average Scoville Heat Units (SHU) |
|---|---|---|
| Standard Jalapeño | Classic green pepper, medium heat, commonly found in grocery stores. | 2,500 – 8,000 |
| Purple Jalapeño | Unique purple color that matures to red; flavor similar but sometimes slightly hotter. | 3,000 – 8,000 |
| Rogue Jalapeño | Longer and thinner than standard jalapeños; can be hotter with a sharper bite. | 5,000 – 9,000 |
| Jalapeño M | Hybrid variety bred for increased heat and thicker walls, good for cooking. | 6,000 – 10,000 |
| Mucho Nacho | Large jalapeño hybrid with robust flavor and higher capsaicin content. | 7,000 – 10,000 |
| Early Jalapeño | Faster-maturing type, usually milder and good for shorter growing seasons. | 2,500 – 6,000 |
| TAM Jalapeño | Developed by Texas A&M, known for disease resistance and consistent heat. | 3,500 – 8,000 |
| Delicious Jalapeño | Thicker flesh, ideal for stuffing and cooking. | 3,000 – 7,000 |
| Fuego Jalapeño | Hotter jalapeño variety, sometimes exceeding typical heat ranges. | 7,000 – 12,000 |
| Black Pearl Jalapeño | Dark purple to black peppers with smoky flavor and medium heat. | 3,000 – 7,000 |
36 Responses
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!
Yes. thanks so much for the info. Thank u for sharing your knowledge. It is greatly appreciated!!
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.
Good to know! Thank you!
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!
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.
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.
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.
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.
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.
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.
Todd, it may be your experience that jalapeno peppers don’t last in the refrigerator, but I have some in mine that are three weeks old, and they are perfectly fine. They 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 like to ask that before you make statements like those above, you at least give it a try for yourself. – RG
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.
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
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.
Thank you for a productive response. Hopefully, some of these commenters will read your response.
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!
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 !
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).
Thanks Marco for this information. You are a braver person than I for tasting the hottest peppers in the world.
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.
Ted, thanks for that confirmation. I still find it hard to believe that the older the peppers are, the hotter they are but I see it with my own jalapenos all the time.
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.
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.
Julia, I’ll have to try this technique but I have to say that I know first hand that jalapeno peppers with lots of white striations are going to be hot.
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.
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.
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
If you find your peppers are to hot just remove the seeds and membrane.
I looked for the salsa recipe, couldn’t find it! Was really hopin to find a good one with the right amount of spice /:
Hi Payten, the recipe for tomatillo sauce is at http://www.reluctantgourmet.com/tomatillo-sauce-recipe/
My recipe for fresh salsa is at http://www.reluctantgourmet.com/fresh-tomato-salsa-recipe-2/
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.
Cheers!
Ben
My experience also told me that they got hotter in the fridge, so I will just go with that belief. Why don’t you test it out before deciding whether to believe or not. And yes, it does have to be some significant times like couple of weeks. A few days won’t do.
Thank you, this is so helpful. I came here because I googled if hot pepper get hotter in the fridge. I have the experience of getting these totally mild and disappointing Thai and Jalapeño peppers from supermarkets and thought they were just terrible, and ready to try purchasing from another supermarket. However, I hate throwing things away, so I left them in the fridge and tried using them up over time. After a few weeks I noticed that they actually got hotter. I thought I might be crazy but your article confirmed it. I will continue to leave them in fridge for as long as I can, and then move them to freezer. I noticed also that the peppers I stored in freezers got quite hot too, maybe just at a slower rate but they can live in freezers pretty much eternally lol
I love Mexican food and learned from a Mexican cook about fresh Jalapeño peppers.
The hot ones have pointed tips and the milder ones have rounded tips. This determination has never steered me wrong. I have a sensitive pallet, so I always remove the seeds and ribs before eating them. This is my rule of thumb in jalapeño selection at the market.