scovilles Is SHU scale logoritmic or linear? Experts, please....

[Indy]

2 cents:

I have to start with: Damn it! I hate math proofs and explanations almost as much as I dislike cheats, fraudsters, and snakeoil-butt salesmen.

It is logarithmic. No bias here, other than against math, perhaps. Avoided math for law school, but for unknown reasons still hit algebra, geometry, and pre-cal-trig, BOO!

If SHU were an exponential in curve we would see pepper heat (SHU) abruptly spiking into infinity across a broad range of genetics, but we see inconsistent bumps in the millions. Sure all the untested peppers out there could prove this wrong, but there is a dispute of true genetic diversity at the upper echelons of the SHU curve, right? ("new scorpion", "new primo", "new pirranah" ((not my table)) new pepper "World War Z" new pepper "what ever tha faq"). That is to say, there is likely a disproportionately small amount of genetic diversity at the height of the curve and therefore, limited peppers bringing heat at the upper ranges of the SHU chart.

Consider this the SHU heat has largely been "curved" around the 10-500,000 range, for example, generic bell, Anaheim, New Mexico --> Jalapeno, Serano --> Hananero, Red Savina, but most superhot heat and genetics are limited/ close relatives/not highly hybridized or stabilized (until proven otherwise) it is likely fair to say the SHU is logarithmic, not linear, because we would see the current pepper diaspora exhibit a more "line like" heat curve, which we do not.

Because we see a large amount of peppers making up the lower part of the curve, as discussed above, and a relative fewer amount of peppers [read: 7-pot, ghost, reaper] (until proven to be genetically diverse) the SHU curve is likely properly to be understood as logarithmic.

Last thought, linear curves involve multiple constants. (I.e. rise/run). Nature is not often one to produce cohesive corralative constants.

Love to be proven wrong that genetics are highly variable and SHU is somehow linear, but hard to imagine in a scientific world, few things are linear.

Wow, I guess I need to tell some teachers and professors they may not have failed me....

Happy to discuss this 2 pence ( for the INTL crowd )

(Edit: To answer your other question, yea despite dude's comments it's not clear or entirely fair to say based on a logarithmic curve one "choche" pepper is "X times hotter than, blah blah blah" that gets to my snakeoil-butt salesman comment. When you are in the stratosphere relative is just that. Relative. What I will say is mutch like the stratosphere and beyond, with hot peppers there is still a lot we don't know. Companion alkaloids, flavinoids, terpenes, it's a new frontier. Let's dictate the next generation -Queue theme song)

Indy

 

[MarcV]

I do agree that the scale is very likely logarithmic. But if it is, I assume that the statement that a bhut with 1M SHU is 200 times as hot as a jalapeño with 5K SHU is probably not correct... (disclaimer - see my signature )

 

[shibby]

I'll give Ed the benefit of the doubt that he was under pressure/stress and said the wrong thing without realizing it. It's easy to get flustered and turn words around and not realize it till later when the spotlight is on ones self.

That said, Ed has been in this game for a while, and I believe he's been quoted the 2-3x comment multiple times pre and post record status, so then I have to say he's just a salesman selling his product and take what he says for a grain of salt.

On to the logarithmic/linear discussion...

The SHU scale is linear. There is no debating that. It is a ratio of capsaicin to a dilution medium (water, oil, whatever). Ratios are linear, period. Rise over run? That's a ratio.

I don't mean to single you out @Indy, but your points are fundamentally incorrect. Using the abundance/variety/count of peppers around 500K or 1M or whatever SHU value to claim logarithmic tendency is an incorrect usage of the SHU scale. This would be akin to saying altitude is logarithmic because as altitudes gets higher we see less and less planes capable of flying at those heights. We see less planes at those heights simply because it's more difficult to achieve and at some point there is a physical barrier (space). I believe what you meant to point out is the bell curve of pepper quantity/variety versus their SHU rating, which is not a scale of heat but a visualization of where majorities and outliers lie on the scale. Even though peppers appear to taper off in quantity in the upper ranges, it in no way changes the scale used to measure them (a linear ratio).

The SHU scale is analogous to gain of an audio system. The gain, on its own, tells you nothing about the audio output (volume/intensity) because it is just a ratio (or multiplier) applied to an input to get a new output. A gain of 10 can't tell you if you're barely going to hear the audio (little to no heat), or if it's going to make you deaf (burn your mouth), until you know the system (person) it applies to. A SHU value of 1000 also means nothing until you know the person (not everyone has the same definition of "hot"). Does that make SHU logarithmic? Absolutely not. It makes it a gain to which every person can adjust their expectations of "heat" (intensity) accordingly. Does that make the definition of "heat" logarithmic? Also no, because not everyone has the same definition of what is hot and the myraid of things that go into making a pepper feel hot.

Last thing I want to point out is people seem to be confusing the SHU with the definition of "heat" or "hotness" of a pepper. The SHU is linear and a scientific measurement regardless of the pepper, person, etc. The definition of "heat" is subjective and will change for everyone, and that is where people seem to be falling into the trap of SHU appears logarithmic because their definition of "heat" appears logarithmic to them. They are not the same scales/definitions.

 

[Siv]

For capsicum fruit:
SHU = capsaicin concentration in ppm x 16. This is as about as simple a linear relationship as you can get.

20,000 ppm = 2% capsaicin = 320,000 SHU (e.g. habanero)
625,000 ppm = 6.25% capsaicin = 1,000,000 SHU (e.g. ghost pepper)
1,000,000 ppm = 100% capsaicin = 16,000,000 SHU (pure capsaicin crystals)

The Scoville scale is a measure of pungency. For capsaicin, what this means is that if you take 1g of pure capsaicin it takes 16,000,000g of water to dilute it to where you can't detect the heat any more. In the old days that's how it was measured - the lab kept diluting the test sample until a panel of taste testers could not detect the heat any more. Now it's done by using a chromatograph to measure the amount of the various capsaicinoids in the sample.

There are other naturally occurring capsaicinoids (molecules that are similar to capsaicin such as dihydrocapsaicin, nordihydrocapsaicin, homocapsaicin) but these all have less pungency than capsaicin. The closest is dihydrocapsaicin which maxes out at 15,000,000 on the SHU scale when pure so less pungent that capsaicin.

There are other compounds that can also be measured on the SHU scale - for example piperine which is the molecule in black pepper that makes it pungent maxes out on the SHU scale at 150,000 so approx 100x less pungent than capsaicin.

And then there are some like RTX which has a SHU rating of 16,000,000,000 - yes, 1000x more pungent that capsaicin!

 

[copper]

So because a famous person said something, we are now doubting such a simple fact? I am honestly confused.

 

[HellfireFarm]

It's defined as a linear scale. I thought this had already been settled?

Scoville scale - Wikipedia

en.wikipedia.org

HPLC method gives results in American Spice Trade Association 1985 "pungency units", which are defined as one part capsaicin equivalent per million parts dried pepper mass. This "parts per million of heat" (ppmH) is found with the following calculation: (capsaicin + 0.82 * dihydrocapsaicin) / standard

- that would be a linear equation

Brittanica explicitly states it is a linear scale:

The ratings work on a linear scale, meaning that a 350,000-SHU habanero is 100 times hotter than a 3,500-SHU jalapeño.

Capsaicin | Definition, Description, Peppers, Scoville Heat Units, & Facts

Capsaicin, the most abundant of the pungent principles of hot peppers (Capsicum). It is an organic nitrogen compound belonging to the lipid group, but it is often erroneously classed among the alkaloids, a family of nitrogenous compounds with marked physiological effects. The name capsaicin was

www.britannica.com

A more complete explanation at https://chili-plants.com/en/interesting-facts/scoville-scale/ says

If one chili is twice as hot as another, twice the amount of water is needed to neutralize the heat. This means in reverse, the Scoville Scala is linear.

 

[Indy]

It's defined as a linear scale. I thought this had already been settled?

Scoville scale - Wikipedia

en.wikipedia.org

- that would be a linear equation

Right.

Except, they go on to explain that's the calculation for PPMH and you need to multiply by a factor of 15 to get SHUs.... starting to not feel linear when you need to perform algebra and then multiply the solution by a factor.... starting to feel like a logarithmic equation....

"Logarithmic scales are extremely useful but are not understood by all. As in all presentations, designers must know their audiences." https://www.forbes.com/sites/naomir...ales-in-my-charts-and-graphs/?sh=3027a3185e67[/URL]

Needless to say SHUs was developed in 1912, the study cited, 1995. Revisited 2008. After researching the underlying info. looks like this was an attempt in the 90s to update and modify testing of SHUs to establish a more accurate quantitative scale. Refresh my memory, what was the hottest pepper in the 90s? Habanero?

I'm sure they had a grasp on the likely upcomming SHU juggernauts such as the ghost, scorpion, reaper, and primo in the 90s, and were likely accounting for it in the scale as we recall how academic institutions shelled out beaucoup bucks to myriad Ag departments to study hot peppers in the 90's, "am I right, Justin?" ("Oh, yeah, Justin quit 6 weeks ago.")

Why is that important, because if they were just basing SHU scale on dilution from H2O for SHUs in the 50K range... (as stated in methodology) we do not know if that is consistent for superhots, because if the scale was a log scale, it wouldn't be, and couldn't be known or anticipated then. (We know testing didnt happen because no superhots existed at the time of the creation of the scale) ere go, it is not fair to say they have established a proper scale and that it is in fact appropriately described as linear.)

Finally, log scales more accurately depict ranges which do not rapidly approach infinity, as opposed to linear and exponential scales which do. This would be fitting for SHUs and peppers as we currently understand them given the current SHU ceiling is established by resiniferatoxin (capped in the billions). [Edit: some info on scales https://www.forbes.com/sites/naomir...ales-in-my-charts-and-graphs/?sh=3027a3185e67]

Reasonable minds can differ, nonetheless SHU scale is not and should not be considered gospel given the derth of information and lack of study done on hot peppers and their complexities.

Love the rousing discussion!

Indy🌶

 

[Indy]

I'll give Ed the benefit of the doubt that he was under pressure/stress and said the wrong thing without realizing it. It's easy to get flustered and turn words around and not realize it till later when the spotlight is on ones self.

That said, Ed has been in this game for a while, and I believe he's been quoted the 2-3x comment multiple times pre and post record status, so then I have to say he's just a salesman selling his product and take what he says for a grain of salt.

On to the logarithmic/linear discussion...

The SHU scale is linear. There is no debating that. It is a ratio of capsaicin to a dilution medium (water, oil, whatever). Ratios are linear, period. Rise over run? That's a ratio.

I don't mean to single you out @Indy, but your points are fundamentally incorrect. Using the abundance/variety/count of peppers around 500K or 1M or whatever SHU value to claim logarithmic tendency is an incorrect usage of the SHU scale. This would be akin to saying altitude is logarithmic because as altitudes gets higher we see less and less planes capable of flying at those heights. We see less planes at those heights simply because it's more difficult to achieve and at some point there is a physical barrier (space). I believe what you meant to point out is the bell curve of pepper quantity/variety versus their SHU rating, which is not a scale of heat but a visualization of where majorities and outliers lie on the scale. Even though peppers appear to taper off in quantity in the upper ranges, it in no way changes the scale used to measure them (a linear ratio).

The SHU scale is analogous to gain of an audio system. The gain, on its own, tells you nothing about the audio output (volume/intensity) because it is just a ratio (or multiplier) applied to an input to get a new output. A gain of 10 can't tell you if you're barely going to hear the audio (little to no heat), or if it's going to make you deaf (burn your mouth), until you know the system (person) it applies to. A SHU value of 1000 also means nothing until you know the person (not everyone has the same definition of "hot"). Does that make SHU logarithmic? Absolutely not. It makes it a gain to which every person can adjust their expectations of "heat" (intensity) accordingly. Does that make the definition of "heat" logarithmic? Also no, because not everyone has the same definition of what is hot and the myraid of things that go into making a pepper feel hot.

Last thing I want to point out is people seem to be confusing the SHU with the definition of "heat" or "hotness" of a pepper. The SHU is linear and a scientific measurement regardless of the pepper, person, etc. The definition of "heat" is subjective and will change for everyone, and that is where people seem to be falling into the trap of SHU appears logarithmic because their definition of "heat" appears logarithmic to them. They are not the same scales/definitions.

@shibby you don't mean to single me out but you did. I love people who talk out of both sides of their mouth.

I am here for positivity and sharing about growing peppers. Love to be singled out and bullied. How about you? Want to talk about your life? Want to discuss your accomplishments as an individual that brought you here. Here to talk about me? Let's talk, jerk!

Right, you interpreted my analogy properly. Frankly, you miss more about my description than my time is worth explaining especially when you clearly possess unimpeachable knowledge. Who am I to point you to the mathmatic principles about logarithmic and linear curves expressing information about properties which may or may not rise to infinity, and how best to scale them.

Fortunately the SHU scale was created in 1912 to surely handle the next 100 years because there has been no significant growth in pepper heat in the last 112 years. Sure. Science is once, always, and forever right and no adjustment is necessary. Looking at you tornados and hurricanes. Looking at you periodic table in 1912, who needs the extra 26 elements discovered. So surely information derived then is infallible. Great! No need for the 19th Amendment of 1919, who needs it, we got it all right in the 1800s. Smfh.

You seem to be either cherry picking facts, or conviently conflating "audio gain" to decibels and alsonmisstating how SHUs are calculated, it is not a simple ratio, it requires calculation of a ratio then multipliplied by a factor. I especially like to see how you showed your work.

You are correct amplification "gain" is a ratio, but not the same as decibels which is the scale of audio intensity, a common mistake, but as you clearly know, decibels are the scale of intensity (SPL) of audio pressure, gain is not the same as to the scale of audio as decibels are. Gain is a ratio decibels are not. Much like Ppmh is linear, SHUs are not.

We can both have fun disceting, right?

Welcome to the forum! Great place to jump in!

Love the discourse and opinions!

@shibby, Zach, I'm curious why did you need to single me out? There's plenty of opinions here. Am I an easy target? Is it fun to bully people on the internet? There's plenty of discussion here, you like to single people out? Why?
Make you feel better about yourself?

Let's talk about it! Let's talk about me!

What's up @shibby?

I'm sorry I made you feel small enough to talk to me.

You don't measure up!

Indy🌶

 

[growyourown]

 

[HellfireFarm]

Except, they go on to explain that's the calculation for PPMH and you need to multiply by a factor of 15 to get SHUs.... starting to not feel linear when you need to perform algebra and then multiply the solution by a factor.... starting to feel like a logarithmic equation....

The algebra you refer to is to get a PPM concentration. That's a simple linear value: 1,000,000 PPM is 100%, 500,000 PPM is 50%, so 1,000,000 is 2x 500,000 is 5x 100,000. Linear.

Then you multiply that value by an integer, not a function. So it's still a linear equation. Try graphing it, you'll still get a straight line:
1 x 15 = 15
2 x 15 = 30
3 x 15 = 45
10 x 15 = 150

150 is ten times 15, and 10 is ten times 1.

The only reason for multiplying by 15 is so the numbers match Scovilles original scale.

If you get a curve when you graph it, then you could be talking logarithmic (and that really depends on the curve). For an example of a logarithmic scale, look at the Richter Scale. Richter 2 is 10x as powerful as Richter 1. 3 is 10x 2, 4 is 10x 3. So 5 Richter is 10,000x 1, not 5x.