Padrón Peppers vs Shishito, 1,417 SHU and a 1-in-10 Gamble

Which bites harder, a Padrón or a shishito?

On the evidence, the Padrón, by a little and only sometimes. One Portuguese trial measured a Padrón at 1,417 SHU, the mildest of the 71 peppers it tested¹. No lab we found prints an SHU figure for a shishito, and one seed seller describes its organic shishito as having no heat at all².

What the two share is the surprise pod your guests talk about. The Galician rule for Padróns is "uns pican e outros non", some bite and some don't³, and UC Master Gardeners put the shishito's odds at about 1 in 10⁴. So on any plate you serve, expect a pod or two to sting whichever bag you bought.

Look at the unit column before you compare rows. The Padrón figures from Spain count fresh tissue, while the shishito figures from Japan count dried placenta only, so the bigger numbers on your shishito rows do not mean a hotter pepper. Both are mild peppers that hide their heat in the pale ribs, and both throw the odd hot pod.

Why can't the Padrón and shishito lab numbers sit on one scale?

Because water and tissue change the count. A Herbón Padrón holds 91 % water by weight³, so a gram of the fresh pod in your hand carries far less of everything than a gram of dried pod. The Japanese team also measured only the placental septum, the part with the most heat⁶, while you eat the whole pepper.

To turn the dry figures into fresh ones, you would need the water content of the shishito's placenta, and the paper does not give it. We leave the conversion out rather than guess. What you can trust are the ratios inside each study, since each lab compared like with like:

So ripeness is your big lever with a Padrón, and seeds are the big lever with a shishito. The Spanish study notes that people eat Padróns green and leave the red ones alone because of their strong pungency⁵; if your bag has started to turn red, save those pods for a sauce. A shishito, even at its seedless worst, stayed well under the hot Japanese Takanotsume grown beside it⁶.

How do Herbón growers keep their Padróns mostly mild?

They select for it every year. The specification for the protected Pemento de Herbón says the local Padrón started out as a hot variety, and that growers removed the plants and fruits with stronger heat until only a light bite remained³. Here is their method, step by step, so you can see where your mild bag comes from:

1. 1

   Taste the seed plants raw

   Growers taste raw pods from the plants they picked as seed parents to check the heat, keeping a mild line and accepting a few slightly hot pods.³

2. 2

   Save seed from red, ripe pods

   They let the chosen pods ripen red, soak them in water so the seeds come off the placenta, and dry the seeds fast.³

3. 3

   Water at the foot of the plant

   Heat above 30 °C with dry air and dry soil raises capsaicin in the fruit, so growers water evenly and keep water off the flowers.³

4. 4

   Pick young and sort by hand

   Pods come off green and immature, by hand, every day in peak season, then packers sort them one by one before bagging.³

That last sort is the part you can copy at your own counter. The packers pull out the pods they expect to burn, and the specification lists the signs they use³:

None of these signs is a promise, so treat them as odds. If you are cooking for someone who hates heat, set the pale, curved, tight ones aside and eat them yourself.

What turns a mild shishito into a hot one?

Mostly a shortage of seeds. In Japan, seedless shishitos even have a name, "stone fruits", and growers have long known they tend to burn⁶. When the Shinshu University team forced seedless fruit with a plant hormone, those fruits held more capsaicinoids than seeded ones and swung far more from pod to pod⁶.

The same paper cites earlier Japanese work in which round-the-clock light, and high temperatures at night, raised the share of hot fruit⁶. If your problem is a pepper you can't find, the shishito swaps go further into the genetics and list what to buy instead.

So your shishito gamble comes from how the fruit set, while your Padrón gamble comes from age and stress. In both cases a pod with fewer seeds is the one to taste first: cut one open, and if you see only a few seeds clinging to the ribs, take a small bite before you plate the batch.

How do the two pods differ on the cutting board?

A shishito is about twice as long. The Herbón specification sets a Padrón at 3.5 to 5.5 cm long and 1.5 to 2 cm wide³, while Johnny's organic shishito averages 3 to 3½ inches, about 7.5 to 9 cm².

Both have thin walls, which is why both blister in a few minutes in your hot pan. The longer shishito sits flat on a grill or a skewer, while the short Padrón rolls around and cooks evenly in a skillet.

The Padrón's long stem helps you too: the specification wants a 3.5 to 6 cm stalk on every pod³. You hold the stem, eat the pod and leave the stem on the plate. Shishitos have shorter stems, so on a skewer you thread them through the shoulder instead.

How many Padróns fill a 400 g bag, and how do you swap by weight?

Somewhere between 89 and 114. Herbón Padróns go to market in bags of about 400 g, and each pod weighs 3.5 to 4.5 g³, so 400 ÷ 4.5 gives 89 and 400 ÷ 3.5 gives 114. Count on your bag to fill two generous plates.

You swap gram for gram, because both are mild pan peppers with thin walls. Here is the arithmetic for the amounts your recipes are likely to ask for:

Your cook times stay close, since both walls are thin. Pull the Padróns a little earlier than you would long shishitos, because the short pods blister all over faster. Salt both at the end, when the skins have puckered, so the salt sticks to the oil.

Should your tapas plate or your skewers get the Padrón?

Pick by the dish and by who sits at the table. UC Master Gardeners tie the Padrón to tapas fried in olive oil and the shishito to roasting and grilling⁴:

If your shop sells only one of the two, buy it and cook it the other's way; your guests will notice the shape before they notice any change in taste. The blistered shishito method works for a skillet of Padróns, and the Herbón festival in early August fries its Padróns in giant pans and serves them with corn bread³.

Can you grow a Galician Padrón season next to a shishito row?

Yes, and the two calendars line up well. Herbón growers start seed from October to January and plant outdoors in April and May³. Johnny's shishito gives its first green fruit about 60 days after transplanting and red fruit at about 80².

1. October–January

   Padrón seedbeds

   Herbón growers prepare seedbeds and sow through the winter, keeping the soil evenly moist until the seedlings come up.³

2. February–March

   Planting under cover

   Unheated tunnels get their plants first, with picking from May.³

3. April–May

   Planting outdoors

   Open-field Padróns go in, with picking from June or July.³

4. About 60 days after transplanting

   First green shishitos

   Red ripe fruit follows at about 80 days.²

5. 1 May to 31 October

   Padrón selling season

   The protected Herbón peppers sell inside this window, packed within 24 hours of picking and rarely after 48.³

Plan for bigger plants than the pods suggest: the specification describes Padrón plants of 80 to 100 cm outdoors and 150 to 200 cm under cover³. Give each its own row and water both at the base through hot spells, since the same specification links dry heat above 30 °C to hotter fruit. In your garden, that means a July heat wave with dry soil can make the pods you pick during it noticeably hotter.

Seed saving is easy with the Padrón, because the plant mostly pollinates itself³. Save seed only from your mildest plants, the way the Herbón growers do, and next year's crop keeps its gentle bite.

Your next step: buy a bag of whichever pepper your market has, sort it with the packers' checklist above, and fry a test handful before the rest. If you want your own plants next summer, the shishito growing guide takes you from seed to first picking, and if Padróns are what you can't find, the Padrón stand-ins list your options by weight.