Potato Bread
Formula No. 1 Flour, 100 lbs.
Water, 60 to 65 lbs.
Sugar, 3 lbs.
Salt, 134 lbs.
Yeast, 1/2 to 1¾ lbs.
Lard, 2 lbs.
Potato flour, 2½ lbs.
Malt, 1 lb.
Method Dissolve the yeast, one half of the malt extract and 4 ozs. of potato flour in 4 qts. of water and place to one side. It is necessary to whip the solution briskly while the potato flour is being added, so that it may be thoroughly dissolved, otherwise the potato flour may become lumpy. Now put the balance of the water, sugar, salt and malt extract in the mixer and stir to dissolve the ingredients. When considerable sugar and salt are used, the potato flour may be sifted together with the sugar and salt and then gradually poured into the water, while it is being briskly stirred with a whip. This offers a way of putting the potato flour into the solution without causing it to become lumpy. Add the flour and the potato flour if it has not previously been added and begin mixing. Then add the yeast. After these ingredients have been incorporated, add the shortening and continue mixing until the dough is smooth. The dough should have a temperature of 78 to 80 degrees when mixed.
Fermentation If a four and a quarter hour fermentation period is required to mature the dough, it may be divided as follows: First rising, 2½ hours; second rising, 1 hour; third rising, 1½ hour. Allow the dough to rest 15 minutes, when it will be ready for dividing.
Formula No. 2 Flour, 100 lbs.
Potato flour, 3 lbs.
Water, 60 to 65 lbs.
Salt, 2 lbs.
Sugar, 1½ lbs.
Malt extract, 1 lb.
Lard, 1 lb.
Yeast, 12 lbs.
Temperature of dough, 80 degrees F. If large dough, reduce temperature to 78 degrees.
Use same method as mentioned for Formula No. 1.
If a 5 hour fermentation period is required: First rising, 3 hours; second rising, 1 hour; third rising, 3/4 hour. To the bench in 15 minutes, when it will be ready for dividing.
This is a wholesale bakery formula written in baker's percentage against a 100 lb sack of flour, not a home recipe. Scaling it down is straightforward arithmetic, but the numbers as printed have some gaps worth knowing about before you commit flour to a bowl.
- Scale by dividingEvery quantity is per 100 lbs of flour, so divide by 100 for a 1 lb flour batch (about 3½ cups) and by 20 for a 5 lb batch. At 1 lb flour, Formula No. 1 works out to roughly 285 g water, 14 g sugar, 9 g lard, 11 g potato flour and 5 g malt extract; the salt depends on how the garbled printed weight is read (see below), and at 2 lbs per 100 would be about 9 g.
- Ambiguous printed weightsThe salt in Formula No. 1 and the yeast figures in both formulas are not usable as printed. Read salt against Formula No. 2, which gives 2 lbs, and set yeast by ordinary practice for a straight dough of this length: roughly 1½ to 2 lbs compressed yeast per 100 lbs flour, which is about 7 to 9 g fresh yeast, or 2 to 3 g instant, per pound of flour.
- Potato flour is not potato starchPotato flour is not necessarily potato starch -- Trade usage of the period is inconsistent: 'potato flour' can mean dried whole cooked potato, ground, but in some sources it means the extracted starch. The two behave differently in dough, so it is worth knowing which you have. Something labelled potato flour, or dried potato flakes ground fine, is the safer reading.
- The hinge: dispersing the potato flourThe whole method exists to keep the potato flour from clumping, since the text says a lump will otherwise form. Whisk it into the water, or sift it with the sugar and salt first as the second option suggests, rather than tipping it dry onto the flour.
- Malt extractAlmost certainly a barley malt extract of the kind sold to bakers, and probably diastatic, though the text says only 'malt extract'. At 1% a diastatic malt supplies enzyme activity and colour for a long fermentation; non-diastatic malt or plain barley syrup gives the flavour but not the enzymatic effect.
- Dough temperature78 to 80F is a target, not an observation. Calculate your water temperature from flour temperature and room temperature rather than guessing, since the fermentation schedule assumes the dough starts in that range.
- Fermentation and punching"First rising, second rising, third rising" means the dough is knocked back and re-covered at each interval; with the 15 minute rest the totals come to the 4¼ and 5 hours stated. Judge by the state of the dough as well as the clock.
- LardAt 1 to 2% it is there for softness and keeping quality. Shortening substitutes by weight; butter carries water as well as fat, so allow for that.
- YieldA full 100 lb batch gives roughly 170 lbs of dough, or something over a hundred 1½ lb pieces. Baking is left to the shop's routine: as a modern starting point, a 1½ lb pan loaf runs about 30 to 35 minutes at 400F, to an internal temperature near 205F.
Potato in bread predates any commercial potato flour: bakers boiled and mashed potatoes into the sponge long before the dried product existed, because the extra starch and sugars fed the yeast, held moisture and kept a loaf soft for a day or two longer. Dried potato flour, sold in bags to bakeshops, turned an inconvenient wet ingredient into something that could be weighed with the salt, and the source here prints two formulas and spends most of its words on how to get the powder into solution without lumps. The generous water, the malt extract and the multi-punch straight dough are all marks of American commercial bread practice in the first decades of the twentieth century, when a formula was expected to arrive as a percentage table.