On Tue, 18 Nov 2003 22:25:23 -0700, "Janet Bostwick"
> wrote:
>
>"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
>
Ah ha! Seek long enough and ye shall find -
http://www.theartisan.net/yeast_treatise_frameset.htm
>Yeast Conversion
>
>The yeast conversion ratio is 100 percent compressed yeast to 40 percent active 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)
>
>Table 1
>
>Compressed Yeast Active Dry Yeast Additional Water
>
>3 oz (90g) 1 .20 oz (36 g) 1.80 oz (54 g)
>6 oz (180 g) 2.40 oz (72g) 3.60 oz (108 g)
>9 oz (270 g) 3.60 oz (108 g) 5.40 oz (162 g)
>12 oz (360 g) 4.80 oz (144 g) 7.20 oz (216 g)
>1 lb. (16 oz) (480 g) 6.40 oz (192 g) 9.60 oz (288 g)
>1 lb. 8 oz (720 g) 9.60 oz (288 g) 14.4 oz (432 g)
>
>Table 2 illustrates the conversion from compressed yeast to instant active dry yeast. (1 oz is rounded to 30 g in the table .)
>
>Table 2
>
>Compressed Yeast Instant Active Dry Yeast Additional Water
>
>3 oz (90g) 1 oz (30 g) 2 oz (60 g)
>6 oz (180 g) 2 oz (60 g) 4 oz (120 g)
>9 oz (270 g) 3 oz (90 g) 3 6 oz (180 g)
>12 oz (360 g) 4 oz (120 g) 8 oz (240 g)
>1 lb. (16 oz) (480 g) 5.28 oz (158 g) 10.72 oz (322 g)
>1 lb. 8 oz (720 g) 7.92 oz (238 g) 16.08 oz (482 g)
>
>The companies specializing in yeast packaged for home baking recommend 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.
>
>
>Table 3
>
>Compressed Yeast Active Dry Yeast Instant Active Dry Yeast
>
>1 cube 2 1/2 tsp 2 tsp
>3/4 cube 1 7/8 tsp 1 1/2 tsp
>1/2 cube 1 1/4 tsp 1 tsp
>1/4 cube 5/8 tsp 1/2 tsp
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.