Uneven cooking / baking (edges burning, center still raw)

You load a full tray. Edges get dark fast, the back corner is basically burned, the middle is still pale and undercooked, and the chef says, “This oven’s killing me.”
That’s not a recipe problem — that’s an airflow problem.

When a commercial oven cooks unevenly, you’re usually dealing with:

  1. Weak or failed convection fan
  2. Blocked or disrupted airflow inside the cavity
  3. Control issues that aren’t reacting evenly to hot and cold zones

I’ll walk you through what’s actually happening, what I look at on service calls, and what will (and won’t) fix it.

What the kitchen usually tells me

I hear the same lines over and over:

  • “Back right burns everything.”
  • “Middle never cooks through.”
  • “Top rack is fast, bottom rack is useless.”
  • “We have to rotate pans constantly or we lose product.”

If you’re spinning trays every 5 minutes just to survive brunch, something’s wrong with the oven, not your staff.

Problem #1: Convection fan not doing its job

Commercial ovens are designed to move hot air. That’s literally how they’re supposed to cook evenly: circulating heated air across product so every area of the cavity is close to the same temperature.

When that airflow drops, you get hot zones and dead zones.

What causes bad convection?

  • Fan motor getting weak
    The fan still turns, but too slowly. Air is not moving hard enough to even out temp across racks.
  • Fan wheel (impeller) coated in grease
    Grease, flour, and carbon build up on the blades. That changes the shape of the blade and kills efficiency. Less air movement = uneven bake.
  • Fan not spinning at all
    Motor failed, bearings seized, or safety interlock is keeping the fan off. When the fan isn’t running, you basically have a hot corner and a cold corner, like an old residential box oven.
  • Fan running but noisy / scraping
    If it’s wobbling, it’s not moving air correctly. It’s just beating itself up.

What I do:

  1. Test the fan under heat, not just “cold spin.” Some fans act fine cold and then drag when they’re hot.
  2. Check for physical damage, buildup, loose blades, or motor bearings going out.
  3. Replace or service the motor / fan assembly if airflow’s not there.

Once convection is restored, you’ll usually see way less “burnt outside, raw middle.”

Problem #2: Airflow blocked inside the cavity

Even if the fan is good, I’ve seen kitchens accidentally kill airflow with how they’re loading product.

Here’s how that looks:

  • Sheet pans are slid all the way back and basically walling off the fan intake.
  • Foil, pans, or stacked hotel pans are blocking side vents or baffles.
  • Somebody lined racks with solid foil “to keep it clean,” which is basically like taping over the air paths.

When you do that, you’re forcing the oven to cook in pockets. One zone is getting constant blast heat, another zone is in a warm “dead bubble,” and you start getting:

  • top left corner: dark brown
  • center: still raw dough in the middle
  • bottom right: barely moving

That’s why you end up rotating trays every 6 minutes and flipping product front-to-back.

What I do:

  • Show the team how air is supposed to flow in that specific model.
  • Point out which racks/positions get starved when the oven is overloaded or blocked.
  • In some cases, reinstall missing baffles / air guides. I see a lot of “we took that panel off for cleaning and never put it back.” That panel is not decoration — it’s how the oven distributes air.

This is especially common in high-volume bakeries and pizzerias where capacity gets pushed past what the oven was actually designed to circulate.

Problem #3: Control and sensor behavior

Let’s say the fan is good and airflow is open. You can still get uneven cooking if the oven is “thinking locally.”

Here’s what I mean:

  • The temperature sensor (probe) is usually mounted in one location.
  • If that location is getting hit with more hot air and other zones are cooler, the control board will believe “we’re at temp” and cut heat… even though half the cavity is actually running cold.

Result:

  • One area runs too hot (often near the probe or near the direct heat path)
  • The rest of the oven struggles to climb
  • Your product comes out lopsided: done on one edge, undercooked in the center

What I do:

  1. Compare real temps across multiple spots in the cavity with a calibrated thermometer.
  2. Watch how aggressively the controller is cycling heat on vs off.
  3. If the controller is being lazy (cutting heat too soon because one small area is hot), we adjust tuning or replace the sensor if it’s reading wrong.

In more advanced ovens with PID-style control, we sometimes have to retune so it doesn’t just “satisfy the probe” and call it good while you’re still serving raw centers.

Problem #4: Mechanical damage / cabinet issues

Less common, but it matters:

  • Torn or flattened door gasket
    If you’re losing heat toward the door, product near the door will cook different than product deep in the cavity. You’ll see pale front rows, burnt back rows.
  • Bent rack supports / warped interior panels
    If heat or air was designed to move across certain channels and those channels are bent, missing, or clogged with burned-on food, you lose balance.
  • Broken or missing interior baffle plates
    These plates help direct airflow. Without them, the fan blasts one corner and ignores the rest.

If you’ve ever said “this oven used to bake even, now it doesn’t,” this is the part I’m looking at. Something changed physically.

Why this kills your kitchen

Uneven bake is not just cosmetic.

  • Ticket timing dies.
    One tray finishes, the next needs “a few more minutes,” the third needs to be flipped, rotated, babied. Your line can’t predict timing.
  • Food waste / re-fire.
    Burned edges, raw center? That’s throwaway food in a commercial kitchen. That is money.
  • Inconsistent product.
    You can’t scale when Batch 1 is beautiful and Batch 2 looks like you used a different recipe.
  • Food safety.
    Undercooked internal temps in the center of the product can get you in trouble, fast.

You shouldn’t have to micromanage every tray just to hit standard.

What we do on a service call for “uneven cooking”

When you tell us “hot spots” or “raw middle,” here’s the usual process:

  1. Run test pans
    We load the oven and run it like you actually use it — not empty. Empty tests are useless because airflow changes under load.
  2. Check convection system
    We inspect and test the fan motor, blade/wheel, bearings, and housing. If the fan isn’t moving air correctly, we repair or replace it.
  3. Restore airflow
    We make sure interior baffles, guides, and shields are in place and not clogged. We point out if loading practices are choking circulation (for example: “you’re blocking the intake with that pan”).
  4. Inspect gasket and heat containment
    If you’re dumping heat out the front, we correct that (door alignment, new gasket). An oven that can’t hold heat evenly can’t cook evenly.
  5. Tune controls
    We verify actual cavity temps in multiple zones and compare to what the control thinks. If needed, we adjust or recalibrate so it’s not shutting off heat early or starving one area.

After that, you should be able to load trays and get predictable color across the pan without babysitting every corner.

FAQ: Uneven cooking in commercial ovens

Why are the edges of my product burning but the center is still raw?
Your oven isn’t circulating hot air evenly. The convection fan may be weak or dirty, airflow might be blocked, or the control is reacting to one hot spot and ignoring cooler areas.

Do I just need to rotate pans during cooking?
Rotating pans is a workaround, not a fix. In a healthy commercial oven, you shouldn’t have to rotate every batch just to get edible results.

Can a bad fan really cause this much difference?
Yes. A failing convection fan turns your “even bake” oven into a hot corner and a cold corner. That’s exactly how you get burned edges and raw centers.

Why does the oven say it’s at temperature but my food still looks underbaked in the middle?
Because the temperature sensor might be sitting in a hotter zone than the rest of the cavity. The controller thinks you’re at temp, but the middle of your load is still cooler.

Can you fix this same day?
Most of the time, yes. Fan motor/impeller issues, airflow blockages, missing baffles, bad gaskets, and control calibration are all things we can diagnose and address on site.

Final word from a tech

If you’re fighting hot spots and undercooked centers, you’re not dealing with “bad luck,” and you’re not bad at baking. Your oven lost even airflow.

What we do is pretty straightforward: we get the convection fan moving the way it should, reopen the air paths, replace worn parts like gaskets or fan motors, and dial in the control so it’s not cooking one corner and ignoring the rest.

After that, you should be able to load a full tray, shut the door, run the timer, and pull consistent product — no constant rotation, no gambling, no “this batch is fine, don’t show Table 12 the other one.”

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