"A.T. Hagan" > wrote in message
...
> On Tue, 18 Nov 2003 22:01:57 GMT, "Graham" > wrote:
>
> >
> >"A.T. Hagan" > wrote in message
> ...
> >> Is the following generally true about interchanging yeast types in
> >> bread making?
> >>
> >>
> >> "To substitute Rapid Acting yeasts for Active Dry yeasts reduce the
> >> amount of Rapid Acting used by 25% from the amount of Active Dry the
> >> recipe calls for then add the dry yeast to the dry ingredients before
> >> mixing.
> >>
> >> To substitute Active Dry for Rapid Acting increase the amount of
> >> Active Dry by 25% over what the recipe calls for of Rapid Acting yeast
> >> and dissolve in warm water (100° to 110°F) with a small amount of
> >> sugar before mixing in with the dry ingredients.
> >>
> >Strictly speaking, in the second example you should increase by 33%.
> >Graham
> >
>
> I won't dispute what you say, but the little (very little) info I
> could find on this says 25% or thereabouts. Why do you say 33%?
>
> It's the standard active dry yeast to rapid acting yeast and vice
> versa conversion that I was most concerned with.
>
> .....Alan.
The small amount of conversion difference in the above example is not
necessarily that important. What is important is that the two yeasts are
used in different ways. The active dry yeast must be hydrated before use to
be most effective. The instant yeast is mixed with the flour. According to
Roy Basan just last week, instant yeast has less tolerance to long
fermentation periods. There is also another dry yeast(instant I believe)
that has a greater tolerance to high sugar recipes. I haven't checked
recently, but I believe there may also be a water temperature requirement
difference between the two. So you probably need to do a little further
research along the lines of yeast properties rather than relying solely upon
strict conversion rates.
Janet