KANSAS CITY — Hamburgers have cult status in the United States. The toasted bun halves with a lavish filling of meat, sauces and salads are an indispensable feature of meals outside the home and meet the taste of a whole nation.

For many Americans, the regular pit stop at a burger restaurant is a cherished part of daily life — and there is a reliable supply throughout the country. McDonald’s, Burger King, Wendy’s, In-N-Out-Burger, Culver’s, Fuddruckers … the arterial roads of the towns and cities are lined with a Who’s Who of the catering trade. And “burger with French fries” tops the menu in most school canteens, diner restaurants and cafes, too.

The heart of every burger is the patty. The unchallenged favorite is the beef variant, followed by fillings made with chicken, fish fillet, pulled pork or vegetarian quinoa.

But not only the filling defines the quality of a burger. It is the bun that gives the popular fast food the final culinary touch. The meat, the toppings and the baked product must form a harmonious triad — that is the only way to ensure ultimate enjoyment.

The quality of a hamburger reveals itself at the first bite. The overall chewing feeling should be soft and homogeneous. So, the optimal burger bun is a small white product made from wheat flour, with a relatively high sugar and fat content.

Burger bun production

Burger buns must meet a number of sensory requirements and must not break, crumble or become soggy. Their production demands flours with a high protein content and soft gluten. In the United States, mixtures of hard red winter wheat and hard red spring wheat are most commonly used.

Many bakeries work with sponge doughs, since the intensive swelling and fermentation processes improve the flavor and shelf life of the finished goods as well as the structure of the crumb.

Highly automated mass production

In the United States, industrial burger bun production is carried out on an extra-large scale. It is not unusual to produce 1 million buns a day. The factories therefore use fully automated, high-output baking lines that guarantee maximum reliability and continuity.

Care must be taken to ensure optimum dough development even at the mixing stage. In order to keep the temperature of the burger bun dough as low as possible despite intensive mixing, iced water or flake ice is used. In continuous mixing systems, technical equipment such as jacket cooling of the mixing container or cooled mixing tools also is used.

Preparation of the dough is followed by a brief dough rest under defined processing parameters. Then, the doughs are portioned and smoothed. Individual proofing takes place in the characteristic bun pans, usually at about 80% humidity and a maximum temperature of 38°C. To ensure that the round moulds in the baking trays are completely filled, the doughs must be soft and relaxed. The buns are baked for a maximum of 10 minutes at 210°C to 260°C, depending on the type of oven.

Uniformity is a must in bun production. Whether it’s weight, diameter, height, degree of browning, or consistency, burger buns must be as alike as peas in a pod. That is not only important for reasons of appearance. Standardized basic products make it easier for the personnel of burger restaurants to comply with the strictly timed procedures for preparation.

Crumb quality

From the baker’s point of view, the quality of the crumb presents the biggest challenge. On the one hand, the bun should have a woolly, fluffy consistency in order to ensure the soft chewing impression. On the other hand, it needs a stable, fine texture that enables it to hold the juicy fillings and sauces. When the bun is toasted, the sugars in it caramelize and close the pores on the cut surfaces. If the texture is too coarse, the crumb could soak up the meat juice from the hamburger or the ketchup and become saturated.

The nature of the crust is equally important. Cracks and blisters must be avoided. The surface must be baked to a golden yellow color throughout, and some varieties have to be coated evenly with sesame seeds. Moreover, the characteristic white ring that comes about through baking in the special burger bun moulds must have no irregularities or gaps.

Buns made to measure

Special care also must be taken with the shape of the products. The height of a standard bun, for example, is 4.6 to 4.9 centimeters. The buns must be neither larger nor smaller than these standard measurements in order to ensure that the halves can be toasted or roasted evenly within the given time.

The phase after baking is important for the shape, too. At many bakeries, the buns emerging fresh from the oven run through a spiral cooling tower so that they cool down as quickly as possible to a packaging temperature of about 35°C. But because of the steep temperature gradient, this procedure involves a risk that the sensitive products may shrink and bend.

The stability of the goods is yet another important quality criterion. Since the buns usually are packed on top of each other, they must be highly elastic in order to maintain their original shape.

Flour and dough improvement play a key role in meeting the complex requirements of burger bun production. Fine tuning of the flour with highly specific compounds of enzymes, ascorbic acid, hydrocolloids, emulsifiers and other agents is essential for strengthening the structure of the dough, improving machinability and enhancing the quality of the baked products.

Fast-food chains define requirements

Cooperation with restaurants such as McDonald’s and Burger King presents the baking industry with a challenge of a very special kind. Each fast-food chain has developed product standards of its own to ensure that its burger buns always look exactly the same. They are baked according to individual recipes, templates and color charts. Buns that do not conform to the standard have to be rejected rigorously.

The following is a list of practical recommendations for avoiding defects in the products and keeping the reject rate as low as possible:

Problem: Uneven shape of the buns.

Possible cause: Dough structure too firm; poor pan flow.

Solution: Soften the gluten and increase the extensibility of the dough, for instance, with protease, cysteine or inactivated yeast (e.g. Alphamalt Pro, EMCEsoft P or EMCErelax 400, resp.).

Problem: Irregularities and holes on the underside of the buns.

Possible cause: Proof time too long; temperature of the proofing chamber too high.

Solution: Use less sponge dough; shorten proof time; increase the stability of the dough with improvers (e.g. EMCEGluten Enhancer 22).

Problem: Uneven or ruptured white ring.

Possible cause: Over-proofing or too much oven rise.

Solution: Adjust proofing and the baking process.

Problem: Wrinkled surface.

Possible cause: Baking temperature too low; collapse of the buns due to mechanical stress.

Solution: Adjust baking temperature; avoid vibration in the proofed dough portions; stabilize the dough matrix with ascorbic acid, glucose oxidase or datem (e.g. Elco P-100 K, Alphamalt Gloxy, Mulgaprime 16).

Problem: Coarse texture

Possible cause: Insufficient mixing of the ingredients of the recipe; too much enzymatic activity; proof time too long; proofing too warm; doughs too warm.

Solution: Cooler doughs and proofing; homogenize the crumb structure with the aid of emulsifying enzyme systems (e.g. Mulgazym DFX, Alphamalt LP 10066).

Problem: Inadequate shelf life.

Possible cause: Low-enzyme, dry-baking flours. Fat or oil content too low.

Solution: Modify the recipe; increase water absorption. Use maltogenic amylases (e.g. Alphamalt Fresh) or combinations of emulsifiers (e.g. Mulgaprime SSL 6 in conjunction with datem Mulgaprime 16) to prolong the softness of the crumb substantially.