Pyler says: How bagging, overwrapping and flow wrapping work
March 14, 2016
by E.J. Pyler and L.A. Gorton
From Chapter 11: Finishing and Packaging — Bagging vs. Overwrapping
At present, virtually all bread reaches the consumer in polyethylene bags, including those variety breads for which some bakers still use an inner wrap. This method of bread packaging had its inception in wholesale bakeries of the Pacific Northwest. Formo (1981) attributed the nearly universal acceptance of the bread bag by the consumer at that time to the following advantages: (a) Bread packaged in polyethylene bags is perceived to retain its freshness longer than conventionally wrapped bread; (b) the package is more readily opened and reclosed tightly; and (c) its ponytail feature renders it more convenient to handle.
The incentives for the baker to adopt bagging of bread and buns and rolls included the greater simplicity of the bagging machines in their design, operation and maintenance compared with the more complex conventional bread wrapping machines. Other advantages were lower acquisition costs, more economical operation, higher packaging speeds and greater dependability that lessen the need for standby equipment.
Bagger operating speeds were rated at 65 to 90 loaves per minute, compared with 45 to 55 loaves per minute for conventional overwrapping machines. Today, wrapper costs have dropped as the technology has evolved, and there is no longer is the significant cost difference between baggers and wrappers. With the advances in wrapping technology and the advent of the horizontal flow wrapper, wrappers have caught up with baggers in speed.
Today the principle points of differentiation between baggers and wrappers are: (a) film selection — bags are traditionally made from polyethylene, while overwrapping uses polypropylene or waxed paper; (b) package image — the tradition “bag” image vs. the wrappers diamond-fold or crimp end-seal; and (c) convenience — the bag remains the easy-open, easy-close package of choice among consumers.
Not to be outdone, the manufacturers of horizontal flow wrappers have teamed with film suppliers to create bread packages that are convenient to open and reseal. Still in its relative infancy, the resealable package’s premium cost and reduced manufacturing efficiency have limited its introduction and acceptance.
A point in favor of horizontal flow wrapping is the technology’s ability to handle diverse film stocks. While a conventional bread overwrapper used waxed paper or polypropylene, the flow wrapper is not limited to these materials. Film manufacturers can supply coextruded film with properties tailored to specific applications. A coextruded film composed of multiple layers can regulate the movement of moisture, oxygen, odors and air into and out of the package. A layer of nylon, for example, can be added to change film strength and alter its tearability, as described earlier in “Baking Science & Technology, 4th ed.,” Vol. II, Chapter 11, Part B.
Formo, A.C. 1981. Bakery packaging in the 1980s. Bakers Digest 55 (5): 88.
More on this topic can be found in “Baking Science & Technology, 4th ed., Vol. II,” Page 586, by E.J. Pyler
and L.A. Gorton. Details are in our store