ksrogers: I am going to try the yeast my friend gave me -- just as an experiment. I think I'll try using your suggested amounts. I also asked this question on the Cooking Forum and Grainlady gave an historical answer that I'm sure is the correct one: Posted by grainlady (My Page) on Sun, Jan 18, 09 at 9:24 SAF-Instant Yeast is a "superyeast". It's a product of genetic engineering. It's air dried instead of oven dried, and looks like tiny worms, compared to the much larger granuals of active dry yeast because of this process. It's a stronger type of yeast, fast-acting, and can be added directly to the dry ingredients rather than being proofed in liquid. The first generation instant yeast was produced to mix directly with dry ingredients for quicker mixing (no proofing necessary). Because the home-users were accustomed to proofing their active dry yeast (which is what I think you are calling "regular yeast"), instant yeast was a failure in home use. They proofed it anyway, which reduced the strength of the yeast, and it didn't perform as well if proofed. The second generation of this product COULD be proofed, OR added directly to the dry ingredients, and is basically what instant yeast is today. Instant yeast was used for many years in Europe before it was introduced in the United States and was first used in commercial application - by being able to add the dry yeast directly to the dry ingredients they were able to save time/money by eliminating yeast that required proofing. If you substitute SAF-Instant yeast for active dry yeast, you need to use 25% less. The "cousin" to the genetically modified "superyeast" Instant Yeast is fast (or quick)-rising yeast. These were reformulated from active dry yeast to preform in "instant" applications. For instance, one brand was simply made into smaller particles to dissolve rapidly and work faster than active dry yeast, rather than a genetic modification. In the 1980's the Automated Bread Machine was developed for home use. Yeast companies begen to develop fast-acting yeast (Quick-Rise, Rapid-Rise and Bread Machine Yeast) for use in Bread Machines. These types were essential for the fast rise needed for the 1-hour cycle. As the name implies, fast-acting yeast shortens the rising time for dough. It is also reduced by 25% if you are substituting it in a recipe calling for active dry yeast. When fast-acting yeast were originally introduced to the home baker, they were developed to make bread faster. You could eliminate proofing in water (add directly to the flour mixture - which saves 10 minutes) and eliminate one rise. After kneading, you cover the dough and allow it to rest for 10 minutes. Form dough, pan, and rise as usual for the final proofing. For both Instant and Fast-Rising Yeast types (which are generally used in the same applications), they are commonly added directly to a portion of dry ingredients. The liquid added to this mixture needs to be 125-130°F to produce a quick rising dough. The warmer temperature is needed because when adding the warm water to a large bulk of ingredients, it quickly cools. Active dry yeast (incorrectly called "regular" yeast) was developed during WWII to replace Cake Yeast. Fleishmann's, the first brand of active dry yeast was developed in 1943. Cake yeast has 70% moisture content, requires refrigeration, has a short life of about 3-weeks, and was difficult to use during the war. Active Dry Yeast is 8% moisture. The development of active dry yeast made it easier to transport (no refrigeration needed) and use. It also had a longer shelf-life. There is one more type of dry yeast - Osmotolerant Instant Active Dry Yeast. This type of yeast is recommended for dough characterized as sweet, salty or low absorption. It's beneficial in certain types of recipes because osmotic tolerance is called for because the amount of available water in these doughs is limited. Fermipan markets osmotolerant instant active dry yeast as Fermipan Brown, and SAF markets osmotolerant instant active dry yeast as SAF Gold. -Grainlady

If you don't do enough baking to keep sourdough starter going in the refrigerator it can be frozen. Spread it out on a cookie sheet covered with parchment paper. Let it air dry for a couple days...until it crumbles easily. Or, you can dry it in a dehydrator. Put it in a Zip-Lock or better still a Lock 'n Lock - type container & freeze crumbled. To use, add a tablespoon or two when making fresh dough. You can also freeze starter in liquid form. /tricia

Most rapid rise yeast has Ascorbic Acid added to make it rise faster, it is basically vitamin C. I'm fine with that. I don't know if the funky smell and too rapid rise (for active dry yeast ) was from the additive or the new process they are using. I don't think they are adding corn syrup, but from the article Robin quoted above, it sounds like they are actually using the corn syrup to make the yeast. "Yeasts are grown in the industry in big tanks with sugary water in the presence of oxygen. When the desired amount of yeast is reached the liquid is pumped out, and the yeast is then dried. Nothing else is added in the production of yeast." I found this after searching on the Internet. So I would guess instead of using a sugar/water solution, Red Star now uses corn syrup to grow their yeast. I just can't understand why they felt they needed to add an emulsifier. I can't say I have ever had a problem with my yeast staying solid. If it worked for so many years I can't see why they would change it. I'm guessing the funky smell is from the corn syrup base they are growing the yeast from, and the undesirably rapid rise is from the emulsifier.

King Arthur Flour pretty much sums up what I've heard. That is that you definitely can substitute (after all, yeast is yeast) and although some suggest you need to use a different amount, KA says what I've heard from a number of sources. It's not really worth changing the amounts. Experiment if you want to though. Don't let me stop you! Here's an excerpt: "You may substitute active dry yeast for the instant yeast called for in our recipes without making any changes in the amount; if the recipe calls for 2 teaspoons of instant yeast, use 2 teaspoons of active dry yeast. (The official word on instant yeast is that you can use 75% the amount of instant yeast to replace active dry yeast in a recipe, but we never bother with the conversion; we find it all tends to even out in the end.)" Did you know yeast will keep birds from nesting in horses' manes? "Yeast is yeast and nest is nest and never the mane shall tweet". (Oh go groan somewhere else!)