The loaf volume during the bread making of a pup loaf (from 100 g of flour) is examined. The results are summarized in Fig.6, which shows an expansion of dough volume from 145 cc to 515 cc by the end of the proofing. During baking the dough was heated from 28-800C, further loaf expansion (ovenspring) of 360 cc occurred in the presence of shortening compared to 220 cc without added shortening. Only 40% of the total CO2 gas produced by yeast fermentation was retained in fully proofed dough. The remaining 60% appeared to be lost during fermentation, punching, molding, and proofing of the dough.