I swear this week I my last spice article for the year (as far as you think…hehe) I wanted to take a look at the differences in why chili peppers vary on spice despite their ranking on the Scoville Scale.  For the context of this research, I took a look at jalapeno as it is low on the Scoville Scale, however I have had some that had zero spice and taste, and some that I swear are as hot as a habanero (all fresh of course, no pickled ones in this scenario).

When it comes to spicy peppers, like jalapeno, the variance in spicy level can depend on a number of factors.  Here are the top 5 –

1. Genetics

• Different jalapeño cultivars naturally produce varying levels of capsaicin—the compound responsible for heat. Some varieties are bred to be milder or hotter.

2. Growing Conditions

• Hotter temperatures and less water often led to spicier peppers.
• Soil quality and sunlight exposure also play a role.

3. Ripeness

• Jalapeños become spicier as they ripen. A green jalapeño is usually milder than a red one, which has had more time to develop capsaicin.

4. Plant Stress

• If the plant is under stress (e.g., from pests, drought, or nutrient deficiency), it may produce more capsaicin as a defense mechanism.

5. Capsaicin Distribution

• Even within a single pepper, the heat isn’t evenly distributed. The white membrane (placenta) inside the pepper holds most of the capsaicin, not the seeds or flesh.

So, when it comes to finding a certain price level of peppers at the store, here is what to look for.  When you want spicier, start looking for stretch marks — they are small brown or white lines on the skin. They indicate the pepper has matured under stress, which often means more heat. Don’t go for the larger ones, smaller and thinner have a tendency to be spicier.   Also check for firmness, the firmer the more likely the spicier they will be.

But if you are looking for milder hot chili peppers because you want more of the taste than the heat (or many other reasons to go milder), look for the following at the store —
A smooth, shiny surface usually means the pepper is younger and milder. Larger peppers of course, if the smaller are spicier, the larger are less spicy. And of course, avoid peppers with the stretch marks.

Overall, there are various reasons as to why a chili pepper doesn’t necessarily follow the Scoville Scale, however if used the right way for you, they can still be very delicious no matter what.