[Sca-cooks] Leven: yeast or sourdough?

[Terry Decker]

> Johnnae quoted:
> <<< OED defines leaven as a noun as "A substance which is added to dough
> to produce fermentation; spec. a quantity of fermenting dough reserved
> from a previous batch to be used for this purpose (cf. sour-dough)."
>
> With quotations such as:
> 1471 RIPLEY Comp. Alch. IX. viii. in Ashm. (1652) 175 Lyke as flower
> of Whete made into Past, Requyreth Ferment whych Leven we call.
> 1699 EVELYN Acetaria 53 Add a Pound of Wheat-flour, fermented with a
> little Levain. >>>
>
> So, does this mean that baking soda, baking powder, hartshorn etc. are not 
> considered leavens, since they don't work through fermentation?
>
> Stefan

A leaven is any substance that when added to dough causes it to rise.  Since 
the process of fermentation was not understood until the 19th Century 
anything that caused the effect of raising dough might easily be considered 
an act of fermentation in period.

Bear