Increasing Yeast for a Larger Bread Recipe

(Rose on Rising)A prior posting addressed the question of whether the yeast in a bread recipe should be increased proportionately to the other ingredients or if less should be used. since this is such an often asked question and various cookbook authors seem to have differing opinions, i decided to consult with two bread experts whom i greatly respect: bill weekley of SAF yeast (lesaffre yeast corp.) and hans welker of fci (the french culinary institute in new york). bill reinforced that environment can play a significant role in yeast quantity, for example in alaska where the kitchen is probably colder, a lot more yeast may be used than say in phoenix arizona, where kitchens tend to be so much warmer. and as i quoted him in “the bread bible,” at high altitude less yeast is required due to the decrease in air pressure. bill also mentioned that if using volume rather than weight, larger formulae tend to be more inconsistent. here’s his advice: for batches of bread dough using up to 10 pounds of flour increase the yeast proportionately to the other ingredients. hans agrees that since home bakers are not working in huge quantities of dough, it is fine to increase the yeast proportionately. he agreed with my supposition that in large volume the yeast would grow faster, but he said, very practically i might add, that if the baker can keep up with production there’s no need to decrease the yeast! i suspect that what is happening in really large batches of dough is that the fermentation of the yeast produces more heat thus speeding the rate of the rise.