I have heard it mentioned that it is the ash in the soil from the volcano that gives Italian tomatoes their great flavour. Is this true or just an old wives tale?

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    There's a certain variety of ginger grown in malaysia called Bentong Ginger that has a similar story, and is better. There might be something to the soil Commented Jul 21, 2023 at 4:34

2 Answers 2


You're most likely thinking about San Marzano tomatoes specifically, which are traditionally grown in the area around Mt. Vesuvius and are, in fact, under a denominazione di origine protetta (DOP), a geographical indication label. The volcanic soil is very fertile and the combination with sunny weather and cooler nights by the sea is said to make for a great growing climate.

San Marzano tomatoes are somewhat fragile and not that suitable for shipping, but they offer superior flavor and don't lose much of it when canned. This has helped them become a premium product (little supply, high quality) that's available year round.

I don't think the Volcanic ash is present in any considerable amounts in other regions in Italy, hence why I think what you heard was specifically referring to San Marzano tomatoes. There are certainly other great tasting tomatoes in Italy though :)

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    Volcanic ash supplies tomatoes with a bunch of minerals they need and thrive on, which makes sense if you consider that tomatoes originated in Central America. I add fertilizers which incorporate ash to my tomato beds at home.
    – FuzzyChef
    Commented Jul 20, 2023 at 18:18
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    @FuzzyChef Do your fertilisers include specifically volcanic ash? Some do, but wood ash is also used. It's interesting that volcanic ash is quite salty (as in NaCl); presumably you wouldn't want to add too much. But there's also lots of K, Ca, & Mg, and S in the form of -SO₄, and they're useful. Other sources of ash have far less S, lots of carbonates instead, and less Na.
    – Chris H
    Commented Jul 21, 2023 at 10:15
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    > Offer superior flavor [citation needed] Commented Jul 21, 2023 at 15:58
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    They do, actually, I special-ordered some stuff. But yeah, it's in very small amounts.
    – FuzzyChef
    Commented Jul 21, 2023 at 20:50

Volcanic soil certainly contributes to the incredible flavor of Italian tomatoes, but it's not the whole story. The nutrient-rich ash provides important minerals for growth and flavor development - no doubt about that. But that Mediterranean climate is crucial too! All that sunny warmth with cool nights really lets those tomatoes mature slowly and develop complex sweetness.

But the real secret is the generations of Italian farmers who've perfected growing tasty tomatoes in that environment. They know how to select the right varieties, when to plant, how to prune the vines just right. And they handle those tomatoes ever so gently after picking so they retain all that beautiful flavor.

At the end of the day, it comes down to passion and tradition. Italian nonnas who lovingly grew tomatoes in their gardens passed down what works to their figli e nipoti. That's how real food culture develops. The volcanic soil gives them a boost, but it's the Italians who've elevated tomatoes into an art form!

So yes, the ash contributes - but it's just one ingredient in the recipe, not the whole dang meal.

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    Do you have a source for any of this? Looks kinda AI-generated.
    – miken32
    Commented Jul 21, 2023 at 22:32
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    @miken32 - Everything that this user posts is AI-generated or edited, and frequently incorrect because of that.
    – Obie 2.0
    Commented Jul 22, 2023 at 22:43
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    Like here. Besides the answer not challenging the basic equation of San Marzano tomatoes with tomatoes from all of Italy, it also attributes the tomatoes' flavor to both hot days and cool nights (any proposed mechanism for this?) and to the gentle handling and knowledge of Italian farmers (farmers in California or Xinjiang are not gentle or knowledgeable?). Also, Xinjiang seems to have hotter days than Naples and maybe even colder nights than Naples in some places, so....
    – Obie 2.0
    Commented Jul 22, 2023 at 23:28
  • Oh, by the way, Mexican farmers have been growing tomatoes since before the Triple Alliance and account for 91% of tomato imports to the USA. Are they just not imparting enough "passion and tradition" to their "hijos y nietos" for most USA tomatoes to be tasty?
    – Obie 2.0
    Commented Jul 22, 2023 at 23:33
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    Do your realize that even your AI-written comments seem off? Your first comment pre-supposes a fact not in evidence, that someone—I suppose Mexican farmers—has lost the capacity to grow flavorful tomatoes. Is that what you think, or what the model spat out? It is probably untrue anyway. Your last comment outright contradicts your answer. Having an LLM write your answers for you, at this point in time, will not lead to correctness or coherence. Perhaps you should feed the following prompt to the LLM: "Is using ChatGPT to write answers better than doing it myself?" The answer may surprise you!
    – Obie 2.0
    Commented Jul 23, 2023 at 2:51

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