Kevin Knott began his working life as an apprentice mechanic in a glass bottle-making plant while studying part time at Sheffield University in the United Kingdom, where he earned his bachelor’s degree in engineering. “Studying at a major university in the Steel Capital of the UK, many aspects of the study work was in thermodynamics and fluid mechanics,” said Mr. Knott, an aspect of his studies that would eventually take him down the path of ovens. This lead him to a final year thesis on the finite element analysis of glass furnace regenerator design.
With a background in thermal engineering, Mr. Knott joined a baking ovens manufacturing company in 1984 as a technical design engineer. This new role involved the thermal and airflow design of baking equipment, including proofers, ovens and coolers. In 1991 he moved to the United States, where he continued working for several oven manufacturers based in both Europe and the US.
Mr. Knott joined Bühler through the acquisition of the Franz Haas Co. in 2018. He has been involved in many different baking processes around the globe, including design, installation, commissioning and troubleshooting. Mr. Knott is currently a technical sales manager working with North American bakery customers.
When installing a new mixer, what are the most common mistakes?
Under-sizing or over-sizing the mixer can be an issue. It is very important to clarify the products to be made. If a mixer is undersized, then you will either have to slow down the production capacity or shorten the mix times, more batches/shift to keep up which leads to underdevelopment of the dough. If the mixer is oversized, then the dough could be unevenly mixed. In addition, the total cycle time, not just the mixing time, needs to be considered.
How can bakers decide whether batch or continuous mixing is right for their operation?
Several critical factors need to be considered, including the number of minor and micro ingredients because the cost of feeders can be high. Bakers also must look at the number of SKUs to be run on the line and how far they differ from the largest volume SKU, and the number of changeovers. A good rule of thumb is a minimum run time of eight hours before changing over.
What are some troubleshooting steps when the finished product isn’t baking correctly?
Always start with the beginning of the process. Check if anything changed with the ingredients being used — different suppliers, different seasons, different storage conditions. Next is possible changes in mixing —human or mechanical —then forming and baking. Make sure the process is always under control.
How can bakers optimize their ovens’ bake profile to prevent checking in their cracker products?
Don’t over-dry the product in the beginning of the process. Allow the product to develop correctly. Use of hybrid baking technology helps a lot. Also important is control of the baking chamber environment. Temperature and humidity are critical.
How should bakers adjust their ovens to accommodate a new type of cookie texture, such as going from crunchy cookies to soft or vice versa?
Control of temperature and humidity are important for this, as well as changes in air flow in convection ovens. Changeover times are much faster in convection systems. Texture can be affected by starch swell, yeast activity and amylase activity.
What are some best practices to achieve the perfect color on cookie and cracker products?
Color of the product takes place when the sugars on the surface carbonize — sugar carbonizes at 273 oF. The more time above 273 oF , the darker the product. Higher flows result in higher heat transfer at the surface of the product and the color starts sooner. Utilizing convection baking particularly in the last phase of the baking process is very important. Especially as we build wider and wider ovens, the control over temperature and air flow across the width become critical for color.
What are the most common reasons a baker isn’t getting the right bake from an oven?
Some typical reasons include variations in dough/batter, variations in the forming process, inconsistencies in temperature control and humidity control. Poor management of the baking curve makes for borderline production, typically trying to bake too fast too soon in the first phase, and running more product than the oven is designed for.
How do you ensure the bake profile is consistent and optimized?
Make sure the oven has solid process controls and is not overloaded. A good recipe management system with supervision of adjustments is critical. It is also important that the operators or people making any changes are well-educated and understand the chemical changes involved in the baking process. Several chemical changes need the product to be in a certain temperature range for a certain amount of time.
How can bakers optimize their ovens’ bake profile to prevent checking in their cracker products?
Don’t over-dry the product in the beginning of the process. Allow the product to develop correctly. Use of hybrid baking technology helps a lot. Also important is control of the baking chamber environment. Temperature and humidity are critical.
