228 PHILIPPINE PALMS 
He found that the inversion of the sucrose began almost im- 
mediately after the sap dripped from the stem, and concluded 
that it was due to the formation of an enzyme. 
Tuba is carried by small boats (bancas) from the place of 
collection to the distilleries. According to Gibbs, the inversion 
is complete, the alcoholic fermentation well under way and 
sometimes completed before the sap arrives at the distillery. 
Occasionally the acetic acid fermentation has progressed to a 
considerable extent. The yield of alcohol obtained from the sap 
varied from 4.1 to 7.5 per cent, the average for 33 distilleries 
being 5.6 per cent. Due to faulty methods, the yield of alcohol 
is not what it should be. The average price paid for the sap 
at the distillery is, according to Gibbs, 0.006 pesos per liter. 
Gibbs says that the alcohol produced from the nipa sap should 
be about 6 per cent of the tuba, and under favorable conditions 
he believes above 7 per cent. With a yield of 6.5 per cent alcohol 
the purchase price of the raw material would be equivalent to a 
cost of 0.0415 pesos to 0.083 pesos per liter for 90 per cent 
alcohol. His estimates would indicate that nipa sap is the 
cheapest known source of alcohol. For manufacturing alcohol, 
nipa possesses several advantages over grains in that it does not 
need purification, pulping, etc. The storage space and fermenta- 
tion vats may also be smaller, since fermentation is complete 
in from six to ten hours and the material ready to be distilled. 
Gibbs estimates that the owner of a nipa area, by selling sap, 
clears about 129.00 pesos per hectare per annum. 
In some distilleries, especially in those near sugar-cane lands, 
molasses is added to the fermenting sap. The molasses, which 
usually contains about 60 per cent of fermentable carbohydrates, 
is sometimes used in amounts equal to that of the tuba. Accord- 
ing to Gibbs the advantages are threefold; the invertase and al- 
coholic ferment in the tuba act with great rapidity upon the 
molasses, providing an easy method for the utilization of the 
latter; the production of alcohol is greatly increased; and when 
there is a shortage in the supply of sap, the uninterrupted run- 
ning of the stills is assured. The use of molasses during a 
portion of the season enables some distilleries to operate the 
entire year. 
TUBA 
The fermented juice (tuba) of the nipa palm is used exten- 
sively by the Filipinos as a beverage. 
VINEGAR 
Considerable quantities of vinegar are manufactured from 
nipa tuba by allowing acetic fermentation to follow alcoholic 
