1. Raw potatoes
Potatoes with a dry matter content of 20-24% are ideal for making French fries while those with a dry matter content of up to 24% are ideal for preparing crisps.
Potato crisps make the highest demands on content of reducing sugars, which should not be more than 0.2-0.3% of the fresh weight. For French fries, the reducing sugar should not be 0.5% of the fresh weight.
2. Peeling and trimming
The potatoes are cleaned and peeled as by abrasion potato peeler. Peeling losses are between 10 and 15%.
3. Cutting or slicing
Making potato sticks for French fries can be done by electric potato cutting machines. The usual size of the cut is from 1/4to 1/2″, square in cross section
4. Potato fry pre-washing
The elongated strips are then washed free of surface starch to minimize adhesion of the strips to each other. The washing is accomplished by fluming washing until the wash water remained substantially clear.
Hot water blanching destroys enzyme activity and leaches out reducing sugars and other chemical constituents that cause off colour. A hot water blancher may be used with for about 3 to about 8 minutes at a temperature of from about 160︒F. to 200︒F. to a generally translucent condition throughout.
6. Hot air dehydration (recommend)
Desirably all surfaces of the strips are exposed to the heated air for from about 5 to about 20 minutes at air temperatures of from about 150︒F. to reduce their moisture content.
7. Potato fry par-frying
Thereafter the partially dehydrated strips are immersed in a deep fat fryer for a short period of time from about 15 to about 60 seconds at a fat temperature of about 300︒F. to about 375 F.
8. Quick freezing
The strips are then frozen by means of a quick freezer to about 0︒F. They may be maintained in their frozen state for many months for use when necessary. They are packaged as desired.
9. Final French fries fry
Just immerse the frozen strips in a deep fat fryer at a temperature of from about 300︒F.to 375︒F. for a period of 1 /2 to about 3 /2 minutes, final French fries will be crisper, taste better and have a better texture internally.