Rack ovens got you maxed out? here’s the next step.

Written By Tim Lara

I spent 25-years selling post tunnel oven processing systems (conveyors, depositing, sandwiching, packaging automation).  Typically, for these systems to operate efficiently a tunnel oven was required to deliver a consistent product in an organized pattern at a higher volume. During this time, I called on multiple potential customers who only utilized rack ovens; here’s how it typically went.

The general scenario was consistent:

  1. The company started years ago with a couple used rack ovens

  2. The business grew and they purchased several more

  3. This expansion continued until present day, currently operating 16 to 64 rack ovens

  4. Over this time they became efficient in staging and moving racks, establishing production standards, perfecting the bake and making a profit

    Any thoughts about changing the process were considered risky to the status quo.

I understood their opinion, rack ovens have many advantages:

  • Lower capital

  • Small footprint

  • Easy to install

  • Gradually add capacity as required

  • Option to effectively produce smaller volumes

  • Baked biscuits in the pans can have a wide range of decorations applied (more of a home made look) 

  • Versatility to bake bread, pastries, cakes or biscuits with the same oven

  • Energy efficient

One challenge is how to produce higher volumes at lower costs while controlling labor.  

Let’s consider a baking tray cycle:

  1. Racks with empty trays are moved to a location close to a wire-cut system

  2. Each tray is removed and fed into the wire cut system, biscuits are deposited in a range of patterns (note: often paper is placed prior to the deposit to minimize sticking)

  3. The filled trays are removed from the wire cut system and placed back into the racks

  4. Full racks are transferred to a staging area to await baking

  5. Each full rack is positioned into a rack oven and the baking starts

  6. Racks with baked biscuits are removed from the oven and transferred to a cooling area

  7. Racks with cooled biscuits are staged near the packaging area

  8. Each tray is removed and the individual biscuits are typically placed on a conveyor for tray packing or directly into a wrapper flight

  9. Empty trays are loaded back into racks and staged to start the cycle again at the wire-cut depositor or for cleaning

In the most common scenario, the trays will be manually moved/handled up to 9-times.

Tunnel advantages over rack ovens

  • Lower cost of goods:

    • Higher production rates

    • Reduced labor

  • Consistent product

  • Efficient designs to decorate, enrobe or sandwich post bake 

  • Improved options for packaging automation 

Production scenario for a typical wire-cut biscuit:

  1. Baking chamber 32-m (105-ft)

  2. Band width 1,200-mm (48-inches)

  3. Biscuits lanes across the width 12 (89-mm diameter biscuit with 6-mm clearance = 95-mm centers)

  4. Bake time of 8-minutes

  5. Capacity, (32,000-mm baking chamber)/(95-mm centers)(12-across)/(8-min) = 502-biscuits/min (30,316/hour)

Note:

For the example above, this is generally a smaller oven with 38.4-square meter of baking chamber.  Higher production ovens can range up to 150-square meters of baking chamber (100-long by 1.5-meters wide).

Conclusion

Does upgrading to a Tunnel Oven make sense for you? 

A good place to start is who are your current customers and what are their expectations. 

Next what are your long-term plans for the business:

  • Grow market share, selling larger contracts to branded and non-branded partners 

  • Continue to develop value-added products, add qualities making your product worth a higher price

If your focus is growth, consider the advantages of spreading the cost of production over a larger amount of goods, gaining Economies of Scale:

  • Cost savings companies experience when production becomes efficient, often by leveraging buying power

  • This occurs when production rises at a rate faster than costs, with costs then being spread over a larger amount of goods

  • A business's size is related to whether it can achieve an economy of scale—larger companies will have more cost savings and higher production levels

  • Not only will the transition to a tunnel oven eventually reduce costs on your current operation, but it will unlock the ability to become more flexible in your offerings and process


There are several additional considerations that must be validated before you begin the transition to a tunnel oven. If you think your bakery may be a good candidate to make the switch, contact LARA Bakehouse and we can start working with you to develop a business strategy.

- Brad Hogan, LARA Bakehouse

Tim Lara