Heat & Capsaicin4 min read
How we verify heat
What Scoville actually measures, why heat is a range rather than one number, and how we source and verify every figure, so the numbers you see are honest and checkable.
Not every pepper in Capsi has a Scoville figure. When it does, heat is still trickier, and more interesting, than a single number suggests. Here's what Scoville actually measures, why you'll see a range instead of one number, and how we decide which numbers to trust.
What Scoville measures
The Scoville scale rates a pepper's pungency in Scoville Heat Units (SHU). It was devised in 1912 by pharmacist Wilbur Scoville, who diluted pepper extract in sugar water until a panel of tasters could no longer detect the burn. The more dilution needed, the higher the SHU. That original "taste panel" method is subjective, so modern labs instead use high-performance liquid chromatography (HPLC), which measures the actual capsaicinoid compounds in the fruit and converts them to an SHU-equivalent. Higher SHU means more capsaicin, and more heat.
Why heat is a range, not one number
The same variety can measure wildly differently from one fruit to the next. Heat depends on:
• Genetics. Even within a variety, seed lines drift. • Ripeness. Capsaicin climbs as a pod matures. • Growing conditions. Heat, drought stress, and soil all push SHU up or down.
So a lab testing a dozen Carolina Reapers might find anything from ~1,000,000 to ~1,600,000 SHU across the batch. A single "1,400,000 SHU" tells you less than the honest span. That's why we lead with a range, and only show a "typical" figure when a lab or official source actually states one. Never an average we invented.
The problem with most pepper numbers
Here's the uncomfortable part: a lot of the Scoville figures you'll find online are unverified, repeated, or inflated. Seed sellers and sauce makers have an incentive to claim the biggest number. "World's hottest" sells, and once an inflated figure is published, other sites, databases, and AI tools copy it until it looks like established fact. Very few sources cite an actual lab test.
We didn't want Capsi to be another link in that chain.
How Capsi sources heat data
Every heat figure in Capsi is tied to a source, and every source carries a trust tier so you can see at a glance how much weight it deserves.
An LLM does the first lookup. Other agents then review that draft against each other: that the paper or page loads, that the Scoville number is the figure that page states, and that the tier matches where the number came from. If they disagree, or the link does not support the number, that measurement is dropped. A person still reviews it before the pepper is published.
• Lab-verified Measured directly using HPLC lab analysis and published in a peer-reviewed scientific journal. This is the gold standard. It includes a real DOI so you can read the full study yourself.
• Official breeder Directly stated by the breeder, cultivar registrar, or a university or government institution that developed or officially tested the variety. These come from the people actually responsible for the pepper.
• Referenced From a reference that explains its own testing method or primary lab work, not a page that only repeats someone else's number.
• Vendor Claim A number from a seed seller, sauce company, or commercial grower. Marketing figures can run hotter than a typical measurement, so we show them separately and label them clearly.
• Unverified Numbers repeated across websites, lists, wikis, or AI summaries with no traceable lab test. This is the most common data on the internet, and the least reliable. Capsi does not use these as the pepper's number.
A pepper can carry more than one source, a lab study and a vendor claim, and we show them all, strongest first. The badge on the headline reflects the best evidence we kept, and the headline range is drawn only from that tier. A vendor's high cannot stretch a Lab-verified range. You still see the vendor's number in the list below it.
Why we stop at Lab-verified
Could we demand even more? In pure scientific terms, yes. Multiple independent labs confirming the same numbers, genetic verification of the exact cultivar, multi-year multi-location trials, and fully open raw data would all be stronger evidence.
We deliberately stop short of that. High-quality peer-reviewed HPLC studies are already uncommon. Most of the thousands of pepper cultivars have never been formally lab-tested in a journal at all. Raising the bar higher would leave nearly every variety showing "Heat not yet documented."
A single peer-reviewed HPLC analysis with a real DOI is therefore the practical high bar we chose. It is rigorous enough to filter out marketing claims and unverified numbers, while still allowing usable data for the varieties that do have solid published work.
For the hardcore enthusiasts who want to dig deeper, that DOI is an excellent starting point. We stop here so the data stays both honest and useful.
When there's no good data
Most pepper cultivars have never been formally lab-tested. That is normal, not a red flag on any one pepper. If the best source we kept is a vendor claim, you still see it, labeled Vendor Claim. Lab-verified and Official breeder then say "No sources found in research." If a review found no credible measurement at all, the page says "No reliable heat data." If it has not been through that review, it says "Heat not yet documented." We do not invent a number.
From number to category
Every documented pepper also carries one of five heat categories: Sweet, Mild, Medium, Hot, or Superhot. These are never a judgment call. The category is calculated from the pepper's typical SHU, using the same boundaries the heat scale on every pepper page draws:
• Sweet: under 100 SHU (bell-pepper territory: no real heat) • Mild: from 100 SHU, under 2,500 • Medium: from 2,500 SHU, under 30,000 (jalapeño and serrano territory) • Hot: from 30,000 SHU, under 350,000 (cayenne through habanero) • Superhot: 350,000 SHU and up (Red Savina, ghost pepper, Carolina Reaper class)
There's no universal standard for these names, but the anchors above match how growers and chileheads actually use them, including reserving "superhot" for the class beyond habanero. Because the category comes straight from the measured number, the label, the scale, and the marker you see on a pepper's page always agree.
Reading a pepper's heat
When you tap the info control on any pepper's Scoville number, you'll see:
• The documented range. The span from the strongest tier we kept. • A verification badge. How much to trust it, at a glance. • A "typically" figure. Only when a lab-verified or official source states one. • The sources. The studies and pages themselves, strongest first.
That's the whole idea: not a prettier list of marketing numbers, but the most honest, checkable heat data we can give you.
Last updated 27 October 2026