wrote in message
...
genetics. they are all sour to one degree or another, but I think calcium
may have
something to do with how sour. Valentine is supposed to be less sour than
other
varieties (I think). Ingrid

"Dvd" wrote:

Anyone have any idea what causes rhubarb to be excessively sour?

I suspect your 'calcium' comment relates to the fact that Rhubarb contains
some oxalic acid (the leaves especially, which is why they are toxic.)
Calcium ions react with oxalic acid to form very insoluble calcium oxalate,
which I vaguely recall is involved in the toxicity mechanism, the oxalate
damages the kidneys. (Reputedly deaths occurred in the UK in world war 2 due
to people eating the leaves. Possibly apocryphal.)

Plant metabolism does howver require some calcium, so just how calcium ions
& oxalic acid co exist is an interesting question. But it clearly could be
related to how sour the plant is. Is the oxalic acid content a significant
contributer to the sourness - I have no idea!

How popular is rhubarb in the USA? Widely eaten & grown in the UK, but far
less on the continent, although you do see it in France some times.

Harvey