Table of Contents
- 1 Background
- 2 History
- 3 Raw Materials
- 4 The Manufacturing Process
- 5 Quality Control
- 6 The Future
- 7 Where to Loarn More
Pretzels are a snack food, which have unique shapes and a hard, shiny
outer surface. They are mass produced using primarily automated machinery.
First developed in the seventh century, pretzels have been called one of
the world’s oldest snack food. A recent market survey found that
the pretzel market in the United States is about $560 million a year with
over 300 million lb (136.2 million kg) of pretzels and pretzel products
being produced. The pretzel market has grown in recent years because
pretzels are considered a more healthy, fat-free snack.
The unique, two looped, knot shape of a pretzel is one of its defining
characteristics. The typical pretzel has a pleasant cracker-like flavor, a
crisp, brittle texture and a brown glossy surface color. Salt crystals are
often sprinkled on its surface to make them taste more appealing. Pretzels
have a moisture content of anywhere from 2-4% and therefore have a very
long shelf life.
While the two-looped knot shaped, hard pretzels may be the most popular
kind of pretzel, there are other kinds which are sold. Soft pretzels are
also manufactured. These products typically have a much higher moisture
content than hard pretzels and are usually larger. They also have a
shorter shelf life. Other shapes are also produced such as thick and thin
rods, pretzel rings, and loops. Additionally, flavored pretzel such as
cheese, rye, caraway, kosher, and butter are also available. Finally,
salt-free pretzels called baldies are now made.
Some historians have said that the pretzel is the oldest snack food ever
developed. It is believed that the pretzel was first developed during 610
by a monk in southern France or northern Italy. Using the dough left over
from bread making, he formed the pretzel shape, which was meant to look
like a child’s arms folded in prayer. He used these creations as
treats for children that learned their prayers. He called the snacks
which means little reward in Latin. The pretiolas eventually found their
way into Germany and Austria where they became known as pretzels. The
pretzels grew in popularity and are said to have been brought over to
America on the Mayflower in 1620. The first pretzels were of the soft
variety. Legend has it that one night a baker who was baking a batch of
pretzels fell asleep. When he woke up all the moisture was cooked out of
them and the hard pretzel was born.
The primary ingredients in pretzel dough include flour, water, yeast,
shortening, and sugar. Each of the ingredients have an important effect on
the dough during manufacture and the properties of the final product.
In pretzel dough making, flour is perhaps the most important ingredient.
It is primarily made up of starch and protein. When water is added, the
flour protein soaks up the water rapidly and reacts with it to form a mass
known as gluten. The gluten can be stretched and formed quite a distance
breaking. This allows pretzels to be formed into the desired shapes.
Sometimes the flour is enriched with various nutrients such as thiamin,
riboflavin, and iron to increase the nutritional value of the product.
Nutrient enrichment is highly regulated by the government so preset limits
are required for a flour to be called enriched. The flour used for
pretzels is called soft wheat flour and has a protein content of about 9%.
It is the largest component in the dough making up about 65-70% of the
Yeast and leavening agents
Pretzel dough is unusual in that it contains both yeast and chemical
leavening agents. The yeast is put in the dough and it produces carbon
dioxide gas as it metabolizes the sugar during fermentation. This gas
creates tiny air pockets in the batter, which helps make the pretzels
lighter and crispier. Yeast is typically supplied as a dry, granular
product. Dry yeast is desirable because it can be stored for a long time
at room temperature. Leavening agents have a similar effect as fermenting
yeast, however they have less effect on the final taste. Chemical
leavening agents include materials such as sodium bicarbonate and ammonium
bicarbonate. In the presence of water, they breakdown chemically to
produce carbon dioxide gas.
Vegetable shortening is a solid form of vegetable fats and oils. Its main
purpose in the dough is to inhibit the formation of the gluten. This helps
the dough stay softer, increases the volume and gives it a crumbly
texture. Fat also allows the dough to remain more palatable for longer. A
typical pretzel recipe may call for about 2-3% vegetable shortening.
Other important ingredients
The pretzel dough would not be possible without the use of water. While
there is less water in pretzel dough than in bread dough, it still makes
up about 30-35% of the recipe. Water is important because it lets the
dough flow and allows the yeast to contact the sugars for fermentation. It
also causes the chemical leavening agents to activate.
The taste of the pretzel is a result of ingredients such as salt, sugar,
and flavorings. Salt is used in the batter at about 1%. It helps to make
the dough stronger in addition to improving the taste. Sugars such as
sucrose or corn syrup are used for about 2% of the pretzel dough. The
sugar has the primary effect of providing food for the yeast cells.
Additionally, it will give a slightly sweet taste although this is very
minimal in pretzel making. Sugar also contributes to the brown color of
Today, the manufacture of pretzels is a nearly completely automated
process, which converts the raw ingredients into a shaped, finished
product. It is estimated that 90% of all pretzels are never touched by
human hands during the manufacturing process. The following steps outline
the procedure used to make typical hard pretzels. Soft pretzels have a
slightly different manufacturing procedure.
1 The pretzel dough is made by factory compounders in large stainless
steel tanks. The flour and warm water are stored in bulk and transferred
to the tanks automatically. The yeast is added and the three ingredients
are blended with high-speed horizontal mixers. When these are adequately
blended, the rest of the ingredients such as sugar, sodium bicarbonate,
vegetable shortening, salt and flavorings are added. Compared to many
dough products such as bread or crackers, pretzel dough is relatively
under mixed. This allows the dough to withstand the punishment of
machining without becoming too sticky or misshapen. The dough is then
allowed to ferment and rise for about 30 minutes.
2 The fermented dough is then transferred to the hopper of the
shape-making equipment. Traditionally, pretzels were made by rolling the
dough and twisting it into the familiar pretzel shape. However, today
most companies have extrusion devices in which the dough is forced
through an opening and stamped into shape with a wire cutter. The excess
dough is recycled to
The dough is mixed in large vats by factory compounders. Once
fermented, the dough is transferred to a hopper, which feeds the
shape-making equipment. The raw pretzels are next conveyed on a wire
mesh belt to an alkaline bath.
the hopper while the stamped pretzels are transferred to a conveyor.
They are passed under rollers to ensure a flat surface and uniformity of
Dipping and salting
3 The raw pretzels are next conveyed on a wire mesh belt to an alkaline
bath. It generally takes several minutes for the pretzels to reach the
bath. This slow transport is deliberate as it allows the pretzels to
under-go another short fermentation or rest period. The alkaline bath is
filled with an aqueous solution of either sodium carbonate or lye. The
resulting bath has an overall 1% concentration of sodium hydroxide. It
also is held at a temperature of about 200° F (93.3° C). The
pretzels are dipped in the bath for 10-20 seconds and typically float
when they are finished. This process gelatinizes the starch on the
pretzel’s surface making it gummy and sticky, allowing the salt
to adhere more readily.
After the pretzels leave the hot bath, they are passed under a machine
which delivers salt crystals to their surface. Modern pretzelmaking
lines use a vibrating salter, which consists of a vibrating plate
driven by a series of small motors and magnets. The salt is evenly
distributed on each pretzel with the excess falling through the wire
mesh belt and being recycled. Generally, the aim is to add about 2%
salt to each pretzel.
4 The in-process pretzels are next transported to long, gas-fired,
Raw pretzels are salted before being transported to long, gasfired,
convection tunnel ovens. The cooking temperature varies from
350-550° F (176.7-286.1° C) and this baking step takes
from about 4-8 minutes. Once baked, the pretzels are dried and
tunnel ovens. The cooking temperature varies from 350-550° F
(176.7-286.1° C) and this baking step takes from about 4-8 minutes.
In the front of the oven, the temperature is significantly higher than
at the end. The initial high heat caramelizes the gelatinized starch,
which produces the characteristic dark brown pretzel color. The
temperature is gradually raised at the start because if heated too fast,
the structure of the pretzels will be weakened which could cause
cracking and breaking during shipping. At the end of the oven the
temperature is cooler to allow moisture in the pretzel to be released.
During this entire baking cycle, the moisture content is reduced to
about 15%. In the next baking phase, the pretzels are kiln dried or oven
dried at about 250° F (119.4° C) for anywhere from 20-40
minutes. This further reduces the moisture content to below 4%.
5 From the ovens, the pretzels are passed along varies conveyors and
allowed to cool. They are then moved along to the packaging machines.
Here the pretzels are weighed and the correct amount is placed in the
packaging. They can be put in many different types of packages including
trays, boxes or bags with cellophane or polyethylene protected coatings.
It is important that this packaging be air tight to prevent the uptake
of moisture by the product. Excessive moisture would cause them to
become soft. The package must also have consumer appealing graphics,
which help it stand out on a store’s shelves. Most major bakeries
distribute products to all of the largest cities in the world.
Consequently, there are very few people who are unfamiliar with pretzel
To maintain a high degree of quality, pretzel manufacturers begin by
thoroughly testing the raw ingredients. These materials are evaluated by
quality control inspectors and subjected to a variety of tests. Various
sensory characteristics such as odor, color, and flavor are evaluated.
Other factors like the particle size of the flour, thickness of
shortening, and pH of liquids are also examined. These tests ensure that
the raw materials will produce a consistent batch of pretzels. On the
final product, many of the same characteristics that were tested on the
raw materials are evaluated. Chemists and technicians check things such as
appearance, texture, flavor, and color. This will certify that each batch
of pretzels shipped to stores will be of the same quality as those
developed in the food laboratory.
Future developments in pretzel manufacturing will likely be found in the
production of new products and improved machines. Marketers will
undoubtedly create new twists on existing products in an effort to make
them taste better, appear more healthy, and more unique. Improvements in
the automatic pretzel making machines will focus on designs, which
increase the baking capacity and speed at which pretzels are made.
Where to Loarn More
Booth, Gordon, ed.
New York: Van Nostrand Reinhold, 1990.
Principles of Cereal Science and Technology.
St. Paul: American Association of Cereal Chemists, 1994.
Macrae, R., et al., ed.
Encyclopedia of Food Science, Food Technology and Nutrition.
San Diego: Academic Press, 1993.
Russel, Margie. “Snackmakers Feel the CRUNCH.”
Food Engineering (May
Walter, Andreas. “Food Marketers Display the Future of