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. 



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 



! )p^Sf^ *^ hours. The water in 



the pans was changed 

 until the last wash 



Fig. 3. — Small apple corer or vegetable peeling knife used wa £erS Were IDractl- 



to remove eyes and diseased spots from potatoes. There I ' 



is a blade at the side, and if a mechanical peeler is not Cally free of starch. 



available knives of this description are better for peeling Trip f rvi n fr nan 



than ordinary paring knives. m ^ . 



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. 



