I'm looking through an old cookbook, ''The Art of German Cooking and Baking'' by Lina Meier (2nd Ed., 1922, Milwaukee, file on wikipedia). There is a recipe for waffles here which calls for "1-2 cents worth of yeast." How much yeast actually is it calling for?
I know how much yeast two American pennies will buy me today: none. Practically, the smallest quantity of yeast I can buy today is an envelope of Fleischmann's active dry yeast, which, according to the internet, weighs about 7 grams (0.25 oz).
I've reproduced the recipe below since it is out of copyright and I've heard yeast is one of those ingredients where you've got to consider what's going on in the rest of the recipe. All I'm concerned about is the 'yeast' ingredient: how much does this mean in today's measurements.
No. 15—YEAST WAFFLES.
Quantity for 6 Persons.
½ lb. of butter ¾ pt. of milk or cream
4 eggs 1–2 cents worth of yeast
¼ cup of sugar ½ lb. of flour
½ grated lemon peel Lard for baking
1 pinch of nutmeg
Preparation: Cream the butter, stir in eggs, sugar, lemon
peel, nutmeg. The yeast is dissolved in the cream which has
been warmed, stirred into the mixture, then flour added to
make a stiff batter. Set to rise in a warm place. Grease the
waffle iron, put in 3 tablespoonfuls of batter, close the iron
and bake the waffles light brown, turning the iron to bake on
both sides. Waffles must be baked and served quickly, because
they are apt to lose their crispness and become tough.
When serving, sprinkle with sugar and cinnamon.
Best Answer
I have no idea about historic yeast prices or measuring units, but there are typical ranges for yeast, and you are pretty flexible on the amount you use.
In bakers' percentages, 2% is a standard (for traditional wet yeast). You use more for rich doughs and short rises, and less for long rises. Your recipe is quite rich and short raised, so my gut feeling would be to start with 5% for the first batch and adjust in the next batch if needed. 5% of half a pound is 11,34 g, which converts to 3,8 g of dry yeast.
You could in principle chuck in the whole 7 g package as Cynetta suggests, but that gets into the range where you get the side effects of too quickly fermented yeast, which consist of off tastes due to ammonia and thiols. You might like that taste (many people whose grandmas baked on the "more is more" principle are accustomed to it), in which case just go for it. Else stay with the lower amount, and give it time to rise well (probably blubb, if it is as liquid as I imagine it from the recipe).
As a side note, you might want to reduce the eggs - home laid eggs in 1922 weren't the 55 g sold nowadays as a standard. Three instead of four would give you a more authentic taste.