29 
In dipping a thermometer must always be used, as the temperature 
has a most decided effect on the curing. Rabak states as follows: 1 
Curing the beans at room temperature either without previous treatment or after 
treatment with water up to 90° C. for a short period of time apparently produces 
beans of the best quality, as judged by the flavoring extracts prepared from the 
samples. It is, however, essential that the temperature (of the water) be not suffi- 
ciently high to destroy the action of the oxidase which is present in the pericarp. A 
destruction of the oxidase would seriously interfere with the formation of the odorous 
constituents of the cured beans. 
Dean and Schlotterbeck state: 2 
That the production of vanillin in the bean is an enzym action has been shown by 
obtaining two green beans from Mexico and heating one to 80° C. in order to destroy 
the natural enzym present, and then submitting both beans to a curing process. 
The bean which had not been heated produced vanillin while the heated one did not. 
Of course, immersion in water heated to 80° or 90° C. for short 
periods does not raise the beans to this temperature. It should be 
borne in mind that the relation between the volume of water and the 
quantity of beans dipped must be such that the dipping will not re- 
duce too greatly the temperature of the water. 
While hot, the beans are placed in a close receptacle to sweat, 
Some growers use half-hogsheads with close-fitting wooden covers, 
the beans first being well wrapped in blankets. Sweating continues 
until the following morning or even the morning after that. 
It has been found in tests at the station that where only very 
small quantities are cured, those wrapped in a blanket and furnished 
no additional heat from without do not retain sufficient heat for 
proper sweating and that many beans develop watery blisters. 
Placing the beans immediately after dipping in a heated chamber to 
begin the drying process reduced the blistering to less than 2 per 
cent, whereas under the system of attempted sweating of small 
quantities without artificial heat the blistered pods in the different 
lots ranged from 20 to 50 per cent. However, samples of the sweated 
and the unsweated beans were examined by an expert in the manu- 
facture of extracts and the unsweated beans were pronounced in- 
ferior to the sweated beans. 
On removal from the sweating box (in which the beans should 
have changed to a chocolate color) the beans are spread for a few 
hours uncovered in the sun. After that they may be sunned under 
blankets for from four to six days. One grower has used a glass 
house with success, and he considers that this has greatly reduced 
the expense of curing. Others, instead of sunning, use artificial heat 
in drying, beginning with a chamber heated to about 110° F. After 
the pods become somewhat wrinkled they are removed from this to 
a less heated chamber for a short period. Whichever process is used 
i Rabak, F. The effect of curing on the aromatic constituents of vanilla beans. Jour. Indus, and Engin. 
Chem., 8 (1916), No. 9, pp. S17, 821. 
2 Dean, J. R., and Schlotterbeck, J. 0. Vanilla extract. Jour. Indus, and Engin. Chem., 8 (1916), 
No. 7, p. 608. 
