for “ Strength ” in Wheat Flour. 
117 
sugar at the disposal of the yeast by its diastatic action on the 
starch of the flour, and in this connexion it may be remarked that 
it appears to be a common practice with bakers to use malt 
extract to increase the size of the loaf. When no. 8 which had 
been marked as low as 20 was found to give off such a compara- 
tively large volume of gas, enquiry was made and it was found 
that the baking tests with it had been made six weeks previously. 
Baker’s Marks 
c.cm. C0 2 
given off by 
20 gms. in 
24 hours 
°/o sugar 
required to 
give COo 
°/ 0 sugar found 
by analysis 
% sugar from 
hydrolysis of 
starch 
1 . 
Manitoba 
96 
270 
5-4 
2-2 
3-2 
2. 
Fife 
90 
325 
6-5 
2-6 
3-9 
3. 
Indian 
73 
274 
5-5 
2-0 
3-5 
4. 
Australian 
68 
227 
4-5 
2-5 
2-0 
5. 
English 
65 
205 
4-1 
1-9 
2-2 
6. 
French 
45 
156 
3T 
1-7 
1-4 
7. 
Rothamsted 
36 
131 
2-6 
1-6 
1-0 
8. 
French 
20 
287 
5-7 
1-8 
3-9 
Gas measured at room temperature and pressure, percentages of 
sugar calculated as glucose. 
It at once occurred to me that it might be a case of rapid im- 
provement in quality on keeping which is sometimes noticed in 
certain flours. I therefore asked that another test should if 
possible be made. This was done, and the report came back that 
it now “marks 40, giving a large loaf but of bad shape.” As 
volume only is in question, this report clearly puts this apparent 
exception in its proper place, and it appears therefore that in all 
the cases which have been tried, the volume of the loaf as deter- 
mined by baking experiments closely follows the volume of carbon 
dioxide evolved by incubating the flour with yeast and water. 
I have baked no. 8 myself, and find that it produces a loaf inter- 
mediate in size between Fife and Indian. 
From the volume of carbon dioxide evolved the approximate 
amount of sugar used up by the yeast can be calculated, and this 
is given as percentage of each flour in the table. Side by side 
with this column are the percentages of sugar in the flours, as 
determined by extracting with cold water, removing the proteids, 
inverting the sugar present in the solution, and estimating the 
cuprous oxide produced by boiling with Fehling’s solution. This 
determination presents considerable difficulties : flour extracts are 
