Is this generally true about baking yeast?

Yes, it is true. Check out the home sites for Red Star Yeast and/or Fleischmann's Yeast Janet

Strictly speaking, in the second example you should increase by 33%. Graham

That's where I built the text from - Fleischman's, Red Star's, and SAF's web sites. But I'd like to get a consensus of opinion of whether it's generally true before I put it into the FAQ.

The more I think of it I'm going to have to make a concerted effort to try to find fresh cake yeast. I can't recall ever having seen it here in Florida or Georgia before. Maybe it spoils too fast down here or something.

.....Alan.

-- Curiosity killed the cat - lack of it is killing mankind.

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.

-- Curiosity killed the cat - lack of it is killing mankind.

Simple mathematics. To convert dry yeast to fast you multiply by 3/4, i.e., reduce by 25%. To convert fast to dry you you do the opposite and multiply by 4/3, i.e., increase by 33.33%. However, the difference is so little that it won't make a significant difference. I was just in a pedantic mood. Graham

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

I doubt that spoilage is a factor because all stores are climate controlled. It is just as hot and humid here in August as it is most of the year in Florida and we still have fresh yeast. It is usually found in or near the refrigerator case where dairy products or packaged bisquites are sold. The display isn't very obvious. In fact, I just noticed the fresh yeast display in the store were I have been shopping for several years because it is with the refrigerated buisquite and I wouldn never think of buying them. Our Winn-Dixie carries fresh yeast, and I know that chain has stores in Florida and Georgia. Maybe you could try there. I don't use fresh yeast because I can get active dry yeast for a small fraction of the cost.

Yes. I do mention that if you're replacing Rapid Acting yeast with standard Active Dry yeast you should still dissolve the yeast in warm liquid first to get it going. But if you're using Rapid Acting in place of Active Dry then blend the dry yeast with the dry ingredients rather than mixing it in with the liquids.

In my baking experience (fairly limited relative to many of you folks) you end up having to tweak the recipe regardless any time you change something important like the type of yeast used so what I'm aiming for is to get them close and then let them tweak to their satisfaction.

I'm still doing Google searches here in rec.food.baking and alt.bread.recipes on yeast, but haven't found anything on Rapid Acting yeast needing a different temperature than standard Active Dry yeast, nor was it mentioned on the yeast manufacturer's web sites that I looked at so if someone would care to knowledgeably address this I'd appreciate it.

I did find this though...

Sounds like with the Rapid Acting stuff you could go either way. Mix it first with water and some flour (or sugar) or just add it straight to the dry ingredients.

.....Alan.

-- Curiosity killed the cat - lack of it is killing mankind.

Ah ha! Seek long enough and ye shall find -

Yeast Conversion>

dry yeast to 33% instant active dry yeast. When converting compressed yeast to active dry yeast or instant active dry yeast in a commercial setting, it is important to take the difference in dry matters into account by making up the difference in weight with water. Table 1 illustrates the conversion from compressed yeast to active dry yeast. (1 oz is rounded to 30 g in the table)

yeast. (1 oz is rounded to 30 g in the table .)

substituting 1 cube compressed yeast (0.6 oz) for 2 1/4 teaspoons active dry yeast for 2 1/4 teaspoons instant active dry yeast. As stated above, a more precise ratio is 100 percent compressed yeast to 40 percent active dry yeast to

33% instant active dry yeast. Table 3 provides a guide to converting compressed yeast to active dry yeast to instant active dry yeast. (We refer those interested in exact conversion measurements in ounces and grams to the Yeast Conversion Chart. The chart allows home bakers to choose whether or not to include additional water in the conversion.) The ratio of active dry yeast to instant active dry yeast is 1.25:1.

That's a fascinating document. Had to print it out so I can read it close tonight.

Now I should be able to wrap up that section and put it to bed.

.....Alan.

-- Curiosity killed the cat - lack of it is killing mankind.

yup all right, the water is alittle warm though a good temp is in between 70-90 peferablly 80 but if there isnt a thermometer handy shoot for body temp

In Alan's first post, the question is about the conversion between Rapid Acting yeast and Active Dry Yeast. Later some following posts talked about instant yeast. As I remember, instant yeast =\= rapid acting yeast. (at least mentioned in King Arthur Flour's Guide to Bread Machine Baking and its FAQ about yeast, and somewhere but forgot where)