On 2005-08-23, stiko > wrote:
> Hi! Here we only have active dry yeast and I happen to have lots of recipes
> with instant (rapid-rise) Can anyone provide me with convertions and how I
> could alter my instant yeast recipes so they work? Thanks

First, note that "rapid rise", "fast acting", and "better for bread
machines" are all likely to mean that it's actually instant yeast, so
this may be a moot point if you can find anything so labeled.

The biggest difference is that active dry yeast, in theory, needs to
be dissolved in warm water ("proofed") before adding to the dough, in
order to wake up the yeast, whereas instant yeast can just be added
along with the rest of the dry ingredients with no separate proofing
step. For this reason, it is often recommended for bread machine
recipes, on the assumption that people baking with a bread machine
can't be bothered with extra steps.

In my experience, all modern dry yeast sold in grocery stores in the
US, whether labelled "rapid rise" or not, is pretty hardy under all
conditions (other than too-high temperatures, which will kill it
quickly), and will still perform pretty well even if not
pre-dissolved. You might end up killing some percentage of the
organisms by doing it this way, which would result in a slightly
slower rise (which, in my opinion, is desirable anyway) and a more
yeasty flavor than you might like.

Another difference, as mentioned by a previous poster, is the potency
of instant vs. active dry: instant yeast contains about 25% more
viable yeast cells (by volume) than active dry yeast, so you'll need
to increase the amount of yeast called for accordingly if you
substitute one for the other, or else be willing to let the dough rise
longer to acheive the same volume.

--
Randall