The reaction between sugar and sulfuric acid is well known to produce a solid column of rising carbon which may leave its container. A very similar rising column may also be produced from high temperature pyrolysis of certain organic substrates.

Is there a name exclusive to the type of reaction that produces a rising column?

  • $\begingroup$ One of my buddies poured himself a beer. Beer going into the glass caused a frothing reaction. Has anyone heard of solid frothing? $\endgroup$ Commented Mar 5, 2016 at 1:54

2 Answers 2


In pyrotechnic chemistry, they might call it a pharoh's snake (or serpent) reaction. To a degree, (or rather 330 °C) pyrolysis of the sugar is occurring (starting at 170 °C).

In cooking, they would call it caramelization, although the term is also applicable in general chemistry. Less specifically, you can call it a "browning reaction"... note- caramelization (non-enzymatic) should not be confused with a Maillard reaction (enzymatic). More specifically, you could call it dehydration or decomposition of sugar with sulfuric acid. Somewhere in-between you might find the term carbonization.

You may also find the terms carbon soufflé and carbon foam interesting.

  • $\begingroup$ Ok, that is the detailed Dad answer. Mom's more to point answer is - No. There is no specific name for such a reaction. $\endgroup$
    – MaxW
    Commented Aug 18, 2016 at 20:46
  • $\begingroup$ @MaxW Ha, you got me! $\endgroup$ Commented Aug 18, 2016 at 22:36
  • $\begingroup$ Plus there are also a number of names referring to the fact that it is something cylindric and it is rising. $\endgroup$
    – Jan
    Commented Aug 18, 2016 at 23:08
  • $\begingroup$ While doing biochar research, sometimes this reaction happens instead of char formation. I was hoping for something more scientific sounding than a d*** mess, which is what I was calling it. This answer works. $\endgroup$ Commented Aug 19, 2016 at 13:45

Concentrated sulfuric acid dehydrates almost any hydroxyl containing organic molecule. This is the specific type of reaction that is occurring.

The reason the carbon-column forms is the intense heat that is released from the reaction. The water vaporizes and rises, carrying the carbon with it.

  • $\begingroup$ Dehydration does not always form a rising column (example youtube.com/watch?v=IhE6CM6Qbws.) Certain pyrolytic reactions do form a rising column. I am looking for a name describing a reaction which produces this phenomena. $\endgroup$ Commented Mar 2, 2016 at 22:12
  • 1
    $\begingroup$ That is a completely different type of dehydration. The dehydration reaction that I was talking about specifically involves the removal of water from an organic compound, not the driving off of water from a hydrated salt. $\endgroup$
    – ringo
    Commented Mar 2, 2016 at 22:16
  • $\begingroup$ Is there a name for this specific form of dehydration? $\endgroup$ Commented Mar 2, 2016 at 22:22
  • $\begingroup$ I believe it would be called acid catalyzed dehydration. $\endgroup$
    – ringo
    Commented Mar 2, 2016 at 22:24
  • 2
    $\begingroup$ How about "Charring"? $\endgroup$ Commented Mar 3, 2016 at 5:44

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