6 Construction Aspects to Consider When Purchasing a Smokehouse

The success of smoked meat products has significantly increased over the last few decades. As one of the oldest methods of food preservation, the smoked meat industry continues to grow as does the demand for dried and smoked protein products. For processors, that means that industrial smokehouses are becoming vital to their lifeline.

Yet industrial smokehouses are one of the biggest investments a processor can make. Making sure to understand what to look for before the buying stage is crucial to the longevity of the investment.

Six Design Aspects

There are six main categories of construction features that will play the biggest role in the quality and consistency of your yields. These features will also determine how much time and money processors will have to spend on maintenance and on replacement component parts.

The six aspects that processors must consider when investing in a smokehouse are include having:

  • Single vs. Multiple Fans
  • Compression vs. Vacuum-Retracting Doors
  • Spray Nozzles vs. Spray Balls
  • Welded Construction vs. Gaskets and Double-Bolted Construction
  • Jack-Shaft Systems vs. Chain-Driven Dampers
  • Exhaust Fan vs. No Exhaust Fan

Making sure to evaluate your potential smokehouse investment based on these aspects will help ensure quality equipment that will give you consistent yields and save you time and money. Below we take a closer look at each of these aspects.

Single Large vs. Multiple Fans

Single Large Fan

Most industrial smokehouses come with a fan rated for that size cabinet, but it is often not big enough to create the CFM of airflow needed to cook your product consistently no matter where it is placed on the rack.

A larger fan size — one rated for the next size up smokehouse — will create anywhere from 15% – 50% more gross CFM in your oven.

A greater CFM is important to consistently cooking product in your oven. CFM is the rate at which a certain volume of air moves in a certain period of time. In the case of a fan, it indicates how much air it can move per minute. So for example, a 1,000 CFM fan can remove all of the air from a box that is 10 ft x 10 ft x 10 ft in one minute.

The more airflow in your industrial smokehouse, the more consistently your product will cook. Going for one oversized fan will be optimal to getting that.

Multiple Fans

Some ovens are built with two fans that operate in opposition to each other in order to create the high and low velocity air streams. For these ovens, all the work of creating and controlling the breakpoint lies in how the fans work in relation to each other. The downsides to more than one fan include being:

  • more of an electrical solution than mechanical
  • complex in design and controls
  • in need of service technician is needed to make even simple repairs
  • Unable to achieve maximum allowable velocity in the oven without two large fans
  • very expensive

Compression Doors vs. Vacuum-Retracting Door Seals

Compression Doors

Compression doors are one of the most common styles of door seals found on an industrial smokehouse or dehydrator.

This style of doors is most like what you would find on the doors in your home: the seal is attached to the door frame and provides leak protection when compressed by the door. They don’t inflate but rather seal when the door is closed and latched to push tightly against the seal.

While compression style seals work well on the doors in your home, they are disadvantageous when used on an industrial smokehouse in that the seals:

  • warp easily, causing leaks around the oven door
  • are only applied to the sides and top of the door frame (as there is no bottom when flush with the floor), so you can’t seal the bottom well
  • need replacement more often than any other style

Vacuum-Retracting Door Seals

Vacuum-retracting door seals are new to the industry and found on only a small number of brand-name industrial smokehouses — even though they provide a distinct advantage over exposed door seals.

Rather than the door seal staying exposed to be run over by the truck or caught in the door frame, vacuum retracting door seals do just that: they retract into the door when the oven cycle is completed.

There are multiple advantages of this style of door, especially when it comes to maintenance:

  • Deflates in seconds, helping to prevent it from ripping when the door is opened quickly
  • Trucks are not running over it during loading and unloading
  • Door seal is embedded into a protective seal and retracted into door, helping to prevent rips and tears

Due to less minor damage that happens in retracting and compression door seals, such as stresses on the door seal that occur when pulled, vacuum-retracting door seals provide a tighter seal that lasts longer than exposed door seals.

Spray Nozzles vs. Spray Balls

Spray Nozzles

The cone shape is the most commonly used spray nozzle style in the ovens of many brand name manufacturers — and the style that most people are familiar with.

As the name suggests, this style of nozzle produces a cone shape, spraying anywhere from a 17° to a 170° angle. The high-pressure spray covers every surface below the nozzle with water and cleaning solution, cleaning the interior cooking cabinet of the oven.

While spray nozzles are the industry standard, they come with a number of disadvantages:

  • Only clean surfaces below the nozzle
  • Require higher PSI to operate
  • Require spraying more locations due to less coverage per nozzle
  • Necessitate special tools to remove

The upside with the spray nozzle, however, is that often it is the cheaper option compared to a spray ball, as it is the most common style on the market.

Spray Ball

The spray ball is a newer option in nozzle styles used for smokehouses. They provide a distinct advantage over the spray cone because rather than spraying in only one direction (down) like the spray cone, the spray ball provides a 360° spray
This provides high-pressure cleaning of not only the interior cabinet of the oven but also up into the supply and return ducts, where proper cleaning typically does not occur.
The advantages also include requiring a lower PSI to operate and not needing any tools for removal. The only potential downside to the spray ball is that it requires a higher GPM rate to operate.

Welded Construction vs Gaskets and Bolted Construction

Heavy-Duty Welded Construction

Nothing spells disaster for your budget and product consistency more than a smokehouse that isn’t built to last. Inferior materials, shoddy work, and poorly welded seams may mean you pay less up front, but will cost you much more in the long run — in repairs, sanitation, and replacement.

Instead, opt for an industrial smokehouse constructed of heavy duty materials that meet sanitary design guidelines. Here are just a few suggestions of what to look for:

  • Tubular stainless steel framing
  • No ‘C’ channel
  • TIG welded wall skims
  • Inside cabinet is completely TIG welded

The better materials and methods used in constructing your smokehouse, the longer it will be able to provide you with cooked product.

Gaskets and Bolted Construction

Some smokehouses use gaskets and bolted construction instead of welding, but those can contribute to more harborage points for bacteria to grow. Over time, you also have to replace the gaskets.

Then if liquid creeps into the interior of the insulating walls, it can cause mold or rust to grow on the stainless steel. This is not only a risk for bacteria growth, but also to equipment efficiency, as temperatures can get too low for proper cooking caused by the hindering of the steel to perform properly. This is a problem many processors run into with this kind of design, so consider that heavy-duty welded construction is going to be the best choice.

Jackshaft Systems vs. Chain-Driven Dampers

Jackshaft Systems

Many manufacturers, especially in America, are switching to a jackshaft system to control the dampers.

Rather than chains that stretch or bounce when the main fan is turned on, a jackshaft system uses a stainless steel shaft to keep the dampers perfectly aligned at 90° as they rotate. Gears located at the end of the shaft turn the dampers as well as connect to the shaft coming from the motor.

These shafts and gears never stretch, never need tensioners, rarely (if ever) fall out of alignment, and need little to no maintenance.

With a jackshaft system, a consistent breakpoint is achieved, consistent product is cooked, and less maintenance is required.

Chain-Driven Dampers

While chain-driven dampers were an industry standard for decades, they fail miserably at keeping the dampers in perfect alignment throughout the cook cycle — and should be avoided when purchasing a new smokehouse.

Here’s a closer look at why:

Loose Breakpoint

A 2° deviation from perfect alignment is all it takes to move the breakpoint to a different location along the oven wall. This jumping around of the breakpoint ruins consistency and yields, as the breakpoint never forms in the same place twice.

Chains are not strong enough nor consistent enough to hold the dampers in perfect alignment.
Turning on the main fan in the smokehouse or dehydrator is enough in a chain driven system to cause the dampers to shake, making the breakpoint move erratically through the oven.

Inconsistent Cooks

Product consistency in a smokehouse relies on consistent airflow in the oven. When the breakpoint hits at the exact same location along the oven wall or floor on every pass and in every batch, your product will cook the same each time.

But when the dampers bounce around, as they do in a chain-driven damper system, the breakpoint does not consistently hit the same location, resulting in product being cooked differently every time.

A loose breakpoint cannot produce a consistent product, and only results in lower yields, inconsistent cooking, and drastic color variation of product throughout the oven.

Maintenance Issues

On top of the breakpoint and product consistency issues, a chain-driven damper system is a headache for maintenance.

Ask any team responsible for maintaining an oven with a chain-driven damper system, and you’ll hear story after story of problems with the chains:

  • Chains stretch causing the dampers to fall out of alignment and wobble as air from the main fan hits them.
  • Chains need tensioners to tighten them back up and work correctly.
  • Chains require regular lubrication to keep them from wearing out and breaking.
  • The dampers need to be aligned frequently, sometimes on a daily basis.

The time spent alone inspecting and maintaining a chain-driven damper system is enough to want to avoid the chain when purchasing a new smokehouse, especially in smaller processing plants that don’t have a team solely dedicated to maintaining their ovens.

Exhaust Fan vs. No Exhaust Fan

Exhaust fan

When using a fan, air circulates without building pressure. This is because there is no new air being introduced in a given enclosed space. Yet when new air is introduced, some of it will look for an outlet to relieve the pressure.

This is also the case for an oven chamber; as it is an enclosed space, the air that circulates within does not necessitate any of its air needing to escape. But by adding new air via a fresh air intake, a smokehouse’s cabinet starts to pressurize.

Naturally, the air will want to neutralize and find an open location within the oven to escape through. This is the purpose of the exhaust fan, that opens out into the atmosphere.

No Exhaust Fan

When it comes to having an exhaust fan or not, we strongly recommend going without one unless you have a long exhaust duct, air scrubbing system, or other type of exhaust restriction.

Having an exhaust fan otherwise can be dangerous because of the pressure it creates in the oven chamber.

Additionally, there’s no need for a fan, as the oven will essentially self-exhaust any pressure build-up from the incoming air supply.

Using a fan costs more money, as well as more time for maintenance and troubleshooting.

Better Design Means Better Product

Having a smokehouse that can deliver repeatable processes, offer the best process yields possible, and are quality built so they last for years are the key to success for every processor.

The above construction aspects come together to make up the best smokehouse money can buy.

Any smokehouse that is missing any of the aforementioned features will hinder consistency of yields, as well as result in costly repairs and bacteria growth that will be harder to address in the long run.