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Ooni Karu Review: The 12″ Multi-Fuel Pizza Oven

The good.
Easily change between wood, charcoal, or gas (or even wood and charcoal at the same time)
Incredibly lightweight and portable for having such fuel versatility
Hot, hot, hot heat with quick preheat time.
The bad.
Karu's torch-style burner is less effective than Koda's pipe burner.
Can only make 12" pizzas (realistically closer to 11")
Free shipping on the Ooni Karu 12

Ever since their successful Kickstarter campaign in 2012, the Ooni team (pronounced “oo-nee”) has been creating some of the most innovative, economical, and convenient outdoor pizza ovens on the market. They aim to make home-made, world-class pizza available to everyone, and the Ooni Karu does just that.

The Ooni Karu 12 Multi-Fuel Pizza Oven

The Ooni Karu 12 Multi-Fuel Pizza Oven is one of their most popular models – small, fast, and affordable with a hybrid fuel source. It’s also lightweight so it’s portable, reaches temperatures of more than 900 degrees, and can be used with charcoal, wood, or gas. The oven takes roughly 15 minutes to reach its maximum temperature, after which a pizza cooks in about a minute.

Karu Features

Ooni Karu Imgur 1
Here’s a quick walk-around of the oven as it was heating up.

The Karu oven reaches a maximum temperature of 932 degrees Fahrenheit (500 degrees Celsius), roughly double the temperature of most traditional ovens. Proper cooking temperature is reached in 20 minutes or less, with many users reaching the proper temperature closer to ten minutes. Our personal test regularly reaches 750F in about 13 minutes during summer months.

Designed to maximize airflow and ensure the pizza cooks evenly, the ideal 932 degrees F temperature is maintained by their patented Flame Keeper technology, a fancy word for a piece of metal that sits beneath the chimney to keep heat in and reduce fuel use. All ovens bought on also come with a free three-year warranty.

  • Size and weight – Unboxed, the oven is 30 x 15 x 31 inches and weighs 26.5 pounds. The oven opening is 3.89 inches in height. The largest pizza size recommended to prepare in the oven is 12 inches in diameter.
  • Materials – The oven is made of high-grade Brushed 430 stainless steel and insulated with ceramic fiber. The 13 x 13 “ stone is a custom-made 0.6”-thick cordierite stone.
  • Fuel usage – You can make an estimated 10 pizzas with 3.3 pounds of fuel, and on gas, it uses .74 pounds per hour.
ooni karu fuel hopper
This photo shows the rear hopper where wood chips or charcoal can be added. In addition, this is where the optional gas addon-on accessory would be installed.

Fuel Choices

As opposed to their models specific to a fuel type, the Karu 12 Multi-Fuel Pizza Oven is a hybrid and allows you to use either wood or charcoal as fuel, combine them, or use the additional propane gas attachment. Personally, we found that a mix of charcoal and wood chips worked best.

To use the oven with propane gas (natural gas is not supported), you’ll need to purchase an additional gas burner attachment which sells for $89.99 at the time of this review.

Lets quickly talk about our experience using each fuel type and the distinct benefits.

Wood – The traditional way to make Neapolitan-style pizza, wood reaches a higher temperature faster and is good not just for pizza but any meat with fast-cooking times, including steak, fish, and vegetables.

wood karu
Wood and charcoal requires the chimney for proper airflow.

100 percent hardwood is recommended, with Oak or Beech being specifically well-suited. For best results use kiln-dried wood. Wood like pine or spruce has a higher resin content than can add unwanted flavors. Never use wood that has been treated or painted.

When starting your fire, use approximately six-inch pieces of wood, and start with 5-6 pieces. Light fuel with natural fire starters or use a blowtorch.

As the wood begins to burn, add additional pieces. You want to add more wood when most of the wood in the oven has burned, but before the flames are gone. When adding wood, it should never overflow the grate.

Charcoal – Charcoal burns more evenly, giving you more control than wood. It makes it easier to maintain a steady and even temperature, and with a lower temperature, you can cook thick-crust pizza or deep-dish pizza. Because most of the charcoal will burn to a small amount of ash, it makes clean up a bit easier than wood. Lump charcoal is recommended, as briquettes will block airflow.

When starting the fire, light two or three pieces. You’ll know the oven is ready for use when the charcoal is glowing white with a red center. If the charcoal is still black with flames, wait. Keep adding charcoal as necessary, making sure you leave room for airflow through the fuel intake hatch.

Charcoal and wood – In combination, these offer the benefits of both. A charcoal base helps keep a steady and even temperature. When you add wood you’ll get not only a higher temperature but that distinct wood-fired aroma and taste as well.

Start with a base of charcoal following the direction above, and add wood after a few minutes to help reach cooking temperature.

gas karu
The chimney is removed when using propane gas.

Propane Gas – The ease of use is perhaps the most popular aspect of gas, it allows you to reach the maximum temperature faster, and can also reach higher temperatures than solid fuel.

To use propane to cook, remove the rear vent cap and attach the burner, remove the chimney, and replace it with the chimney cap. Turn the gas control nob until you heal a clicking noise and the fuel ignites. Turning the knob adjusts the flame and temperature.

Assembly and First Cook

What’s in the box?

The oven comes with four parts, the main body, chimney, fuel hatch, and the rear vent cap.

ooni design
  • Main body – The main body comes fully assembled. It has three legs with non-slip feet for stability.
  • Chimney – The chimney is easily attached and is used with wood or charcoal only.
  • Fuel hatch – The removable hatch allows you to add more fuel, and closing it prevents heat from escaping.
  • Rear vent cap – The vent cap is used when using solid fuel to control flames. The vent control allows you to control the airflow. Note that when the oven is in use the vent gets hot, so you’ll need to wear heat-resistant gloves to handle it.

Setting up the oven

Ooni Karu is designed only for outdoor use, as proper ventilation is critical. You’ll need to place the oven on a table sturdy enough to hold the oven and any ingredients and dishes you’ll be using. They recommend wood or stone surfaces and do not recommend glass or plastic. To ensure proper ventilation the oven needs at least three feet of space on all sides.

Safety precautions

Because of the high temperatures involved, the following basic safety is essential.

  • Your oven should not be left unattended while in use.
  • Be sure to keep children and pets away from a lit oven.
  • Don’t use the oven in high winds.
  • Be sure to remove the chimney cap.
  • If you are using the gas burners, you must check the tank, hose, and regulator connections and check for leaks before each use and replace the chimney with the chimney cap.

Before the first cook – seasoning

Before your first time cooking in the oven, you’ll have to “season” it to get rid of oils and coatings left-over from the manufacturing process. This is accomplished by running it at the top temperature for at least 30 minutes. Once cooled wipe the inside with a dry paper towel. The seasoning process also helps you get acquainted with the oven so that you’ll be familiar with it when it’s time to cook your first pizza.

lighting karu
Note – these images are not of the first burn off/season. We had already used the oven multiple times.

Using the Karu oven

To start the oven you just add some initial charcoal or wood through the fuel intake hatch and light with natural fire-starters or a blowtorch. As the temperature increases, slowly add more fuel to help maintain proper airflow. The thermometer will let you know when the proper temperature is reached. After that just add your pizza using a peel and wait about a minute before pulling it out of the oven.

pizza test

While Ooni recommends fuel regulation as the optimal way to maintain proper temperature, the vent allows for a bit of fine-tuning. Opening the vent will allow more oxygen in, making the fire burn more and increase the temperature. Closing it will do the opposite, which will provide a lower heat and create a smokier taste.

If your temperature goes above 932, stop adding fuel and allow the oven to cool. Removing the hatch will also allow more heat out and will lower the temperature.

If you are changing from charcoal or wood to gas while cooking, you need to wait for the oven to cool before attaching the gas burner.

When you are done cooking, just let the oven burn the remaining fuel and cool, which can take up to an hour, before moving or cleaning the oven.

Karu pizza

Karu oven maintenance

Because of the high cooking temperature, the oven will burn off most flour or food remnants in the oven and stone. A dry paper towel is recommended to clean the inside if needed. The outside can be wiped with a damp cloth. Make sure you let the oven cool for at least an hour before cleaning or moving it.

Before each use, clear excess ash and fuel from the grate with a hard-cleaning brush.

What we love

  • Convenience – The oven’s small size and multiple fuel choices make it well-suited for a wide range of cooking options.
  • Affordability – Compared to other ovens that reach high temperatures, the Ooni is much more affordable.
  • Great pizza – The oven allows anyone to make great-tasting, Neopolitan-style pizza right at home.

What can use improvement

It’s hard to find much room for improvement in this oven. There’s still a little bit of a learning curve for those who never used a residential pizza oven before, but 1 or 2 times testing it out before cooking is all you should need.

For anyone looking to make traditional-style pizza at home with a convenient and affordable pizza oven, the Ooni Karu 12 Multi-Fuel Pizza Oven is worth considering.

Written by Derek Gaughan

Derek Gaughan is the Founder and Content Lead for Pala Pizza. He's been featured in PMQ Magazine, The Washington Post, and Home & Gardens. Derek holds an MBA from Pennsylvania State University and is a trained pizzaiolo, specializing in New York style, Neapolitan, and Detroit pizzas.

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