6 BULLETIN 1055, U. S. DEPARTMENT OF AGRICULTURE. 
its smoking point is too low to make it a competitor of the cheaper 
oils. No fat with a smoking point of less than 220° C. (428° F.) is 
desirable for frying potato chips. Overheated fat is unwholesome 
and imparts a scorched flavor to the food. 3 
STANDARD METHOD OF MAKING CHIPS FOR THE TESTS. 
As a result of the first year’s experiments, the following uniform 
method of procedure was developed and used as a standard: 
Six or seven medium-sized potatoes, with a total weight of approxi- 
mately 1,000 grams, were first weighed on a torsion balance (fig. 1), 
then peeled in a vegetable peeler, all eyes or diseased spots removed 
(figs. 2 and 3), and the peeled potatoes weighed again. They were 
then sliced with a vegetable cutter into slices one-sixteenth of an inch 
thick; these slices were weighed (fig. 4) and put to soak in cold water, 
care being taken to keep each lot or variety in a separate pan. Each 
lot was washed in cold running water until the next lot had been 
weighed, peeled, sliced, and weighed again. It was then placed in a 
pan of cold water, while the second lot took its place under the faucet 
of running water (fig.5). By the time the last lot had been prepared 
and placed under the faucet, the first lots had been soaking in cold 
water for several 
hours. The water in 
the pans was changed 
until the last wash 
Fic. Cages apple corer es Vegetable peeling ie Pee waters were practi- 
to remove eyes and diseased spots from potatoes. Ther« 
is a blade at the side, and if a mechanical peeler is not cally free of starch. 
Se ee are better for peeling The frying pan 
and oil were weighed 
before and after the chips were cooked, to determine just how much 
oil was used in making a given weight of chips. A thermometer 
was hung in the frying pan, the bulb being covered with oil, in 
order that uniform temperatures might be secured for each experi- 
‘ment. When the oil reached 210° C. (410° F.) the thermometer 
was removed to another pan of hot oil, the inner basket containing 
the raw sliced potatoes lowered into the hot fat (fig. 6), and the 
slices stirred constantly with a long-handled spoon. ‘The slices 
were not dried, but as much of the water as possible was removed 
by shaking before lowering them into the hot fat. When the water 
on the potatoes had boiled away and the slices were crisp and 
golden brown, the frying basket was raised, the excess oil drained - 
off, and the chips emptied on brown paper to dry (fig. 7). They 
were later weighed (fig. 8), sprinkled lightly with salt, and scored by 
the three judges. 
