62 COCOA AND CHOCOLATE 



enzyme and tannin, hitherto separate, become mixed, 

 and hence able actively to absorb oxygen. The action 

 of oxygen on the tannin also accounts for the loss of 

 astringency on fermentation, and it may be well to 

 point out that fermentation increases the internal sur- 

 face of the bean exposed to air and oxvgen. The bean, 

 during fermentation, actually sucks in liquid from the 

 surrounding pulp and becomes plumper and fuller. 

 On drying, however, the skin, which has been ex- 

 panded to its utmost, wrinkles up as the interior con- 

 tracts and no longer fits tightly to the bean, and the 

 cotyledons having been thrust apart by the liquid, 

 no longer hold together so closely. This accounts for 

 the open appearance of a fermented bean. As on drying 

 large interspaces are produced, these allow the air to 

 circulate more freely and expose a greater surface of 

 the bean to the action of oxygen. Since the liquids in all 

 living matter presumably contain some dissolved 

 oxygen, the problem is to account for the fact that the 

 tannin in the unfermented bean remains unoxidised, 

 whilst that in the fermented bean is easily oxidised. 

 The above affords a partial explanation, and seems 

 fairly satisfactory when taken with my previous sug- 

 gestion, namely, that during fermentation the bean is 

 rendered pervious to water, which, on distributing 

 itself throughout the bean, dissolves the isolated masses 

 of tannin and diffuses it evenly, so that it encounters 

 and becomes mixed with the enzymes. From this it 

 will be evident that the major part of the oxidation of 

 the tannin occurs during drying, and hence the im- 

 portance of this, both from the point of view of the 

 keeping properties of the cacao, and its colour, taste 

 and aroma. 



It will be realised from the above that there is still 

 a vast amount of work to be done before the chemist 

 will be in a position to obtain the more desirable 

 aromas and flavours. Having found the necessary 

 conditions, scientifically trained overseers will be re- 

 quired to produce them, and for this they will need 



