Soda was [Sca-cooks] steam-baking

[Decker, Terry D.]

There is a little difference between sodium carbonate (Na2CO3) and washing
soda (Na2CO3.10H2O).  Washing soda is sodium carbonate decahydrate, or
sodium carbonate with ten water molecules bonded to it.  Sodium carbonate is
a white powder.  Washing soda is transparent and crystalline.  The modern
process for manufacturing sodium carbonate first produces sodium carbonate
decahydrate which is then heated to release the water molecules.  For our
purposes, they are interchangeable.

Sodium bicarbonate (NaHCO3) is sodium carbonate with one of the sodium ions
replaced by a hydrogen ion.

Both sodium carbonate and sodium bicarbonate outgas carbon dioxide in the
presence of acid, however sodium bicarbonate produces a second outgassing at
50 C (122 F) which is a reason to prefer it in baking.

Bear

> For example, soda --and note that "baking soda", or sodium
> bicarbonate, may not even be what is intended here-- was used by the
> Romans as a green color fixative and tenderizer for vegetables, just
> as it sometimes is in recent European (esp. French) cookery. Modern
> Chinese cookery also employs baking soda as a meat tenderizer,
> usually for tougher steaks and tripe (you wash it off carefully
> before cooking, like the lye solution in the preparation of
> lutefisk). The Roman cooking soda appears to be what we call "washing
> soda" or sodium carbonate, but I don't know which soda Dr. Buell is
> referring to.
>
> Adamantius